Masters Degrees (Animal, Wildlife and Grassland Sciences)

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Open Access
Animal performance and utilization of opuntia-based diets by sheep
(University of the Free State, 2008-05) Einkamerer, Ockert Bernard; de Waal, H. O.
English: Incremental levels of sun-dried and coarsely ground cactus pear (Opuntia ficus-indica var.Algerian) cladodes were used to substitute part of the lucerne hay in balanced diets and fed to 28 Dorper wethers. The extent to which sun-dried and coarsely ground Opuntia cladodes can be incorporated in balanced sheep diets without effecting sheep performance was investigated over a period of 70 days. The three treatment diets (T0, T24 and T36) used in this study comprised respectively (air-dry basis) 0, 240 and 360 g/kg sun-dried, coarsely ground Opuntia; 660, 410 and 285 g/kg coarsely ground lucerne hay; 300 g/kg yellow maize meal; 0, 10 and 15 g/kg feed grade urea; and 40 g/kg molasses meal. The dry matter intake (DMI) varied little between diets but the apparent digestibility increased [P<0.05; 71.4% (T0) vs. 75.6% (T36)]. The average daily gain (ADG) of the wethers decreased slightly as Opuntia inclusion increased. This suggests that the overall effects of the diets on the performance of the wethers were small. As the inclusion level of Opuntia increased in the diets, the water intake of the wethers also increased (P<0.05; T0 vs. T36), while urine excretion showed little increase (P>0.05). The faeces DM excreted remained the same for all diets, but with the higher levels of Opuntia inclusion the DM content of the faeces excreted visibly decreased considerably. It is suggested that the mucilage ingested via the Opuntia and present in the digestive tract of the wethers may have interacted with the water fraction in the digesta, rendering some of the water unavailable for absorption. Hence, the wethers were compelled to drink more water to compensate for this extra water loss via the faeces. The wetter faeces were assumed to be the result of diarrhoea by some researchers, but the wet faeces lacked the customary foul smell associated with diarrhoea. Opuntia inclusion in the diets had no effect on carcass characteristics of the wethers (weight, fat thickness, surface area of musculus longissimus dorsi and relative tissue coefficients). This suggests that the effect of Opuntia in the treatment diets on the carcass weight and quality of the wethers were small. From these results, it seems that, irrespective of the dietary treatment, adequate nutrients for sheep maintenance and production was supplied by the diets. Sun-dried and ground Opuntia cladodes can be seen as an alternative feed supplement in semi-arid and arid regions of most countries that can be included in sheep maintenance or production diets without any detrimental effects on animal performance or carcass quality. It is recommended that research should focus on the formulation of Opuntia-based production diets with a high energy content, to be used in feedlots. The effect of mucilage on the wetter faeces excreted by sheep 61 on Opuntia-based diets and what happens in the alimentary canal also needs further investigation.
Open Access
Breed effects and non additive genetic variation in indigenous and commercial sheep in an extensive environment
(University of the Free State, 2019-06) Kao, 'Mamolleloa A.; Van Wyk, J. B.; Cloete, S. W. P.
The first part of the study compared a commercial, the Dorper as an arguably adapted commercial breed to the Namaqua Afrikaner as an unselected, indigenous, far-tail breed. The Dorper conclusively outperformed the Namaqua Afrikaner with reference to live weight and growth traits. On the other hand, Namaqua Afrikaner lambs were superior to Dorpers for an adaptive trait like total tick count. Lamb survival was unaffected by breed. When meat traits were considered, it was evident that Dorper lambs outperformed their Namaqua Afrikaner contemporaries for important attributes associated with size and meat yield, namely carcass weight and dressing percentage. Dorper carcasses also attained better grades and were more tender according to instrumental measurements (Warner Brazler equipment). Dorper lambs were fatter than Namaqua Afrikaner lambs, as derived from the backfat thickness at the 13th rib and the rump. While leaner meat would be preferred by health-conscious consumers, it is important to note that, under the conditions of the study, Dorper carcasses were more likely to be in the preferred grades. In the second part of the study, Dorpers were evaluated against the SA Mutton Merino (SAMM; the most numerous dual-purpose breed in South Africa), as well as the reciprocal cross between the two breeds. No conclusive breed differences were found for weight traits, lamb survival, tick counts or meat traits. However, there was a suggestion that lamb survival of Dorpers was higher than that of their SAMM contemporaries (P = 0.08), but significance could not be demonstrated. Crossbred progeny outperformed the midparent value by 6.3% for weaning weight. The corresponding study on meat traits was constrained by low numbers. However, it was evident that the observed heterosis for weaning weight was also present a later growth stage. Direct heterosis estimates amounted to 7.7% for slaughter weight and 7.1% for carcass weight. These estimates were consistent with the literature for the expected level of heterosis for early growth when assessed in fairly divergent sheep breeds. This outcome once again reiterated that crossbreeding may have a definite role to play at the commercial level in the South African sheep industry. Further studies on the comparison of indigenous genetic resources with commercial breeds, as well as crossbreeding studies with the variety of available breeds were recommended.
Open Access
Characterization and cryopreservation of semen of four South African chicken breeds
(University of the Free State, 2009-11) Mosenene, Thatohatsi Madaniel Bernice; Greyling, J. P. C.; Schwalbach, L. M. J.
The aim of the study was to characterize and evaluate the quality of fresh semen of 4 breeds of chicken and the susceptibility of cockerel semen to a cryopreservation protocol, assessed microscopically for sperm motility and morphology and ultimately fertilizing ability following AI. The differences between breeds were determined by comparing the fertilizing ability and hatchability of fresh and frozen-thawed semen. The study was carried out at Glen Agricultural Development Institute and at the University of the Free State. Four chicken breeds, namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn, were used. Qualitative characterization of the semen was performed in 28 cockerels (7 per breed). Semen was collected using the massage technique twice a week in the first trial. The eosin-nigrosin staining technique was used to microscopically evaluate the morphology of the sperm from the different breeds. The fresh semen parameters evaluated were ejaculate volume, semen colour, semen pH, sperm concentration, the percentage live and dead sperm, sperm motility and the abnormalities of the sperm. The percentage live and dead sperm, sperm motility and abnormalities were also evaluated for the frozen-thawed cockerel semen. During the second phase of the study, semen was collected 3 times per week from the same cockerels. Semen was frozen using a fast–freezing procedure on dry ice, with 10% DMSO as the cryoprotectant. AI was performed on 4 different breeds of hens (20 hens per breed) (Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn), using fresh semen (control) and frozen-thawed semen. During AI of each breed, 10 hens were inseminated with fresh and the remaining 10 hens with frozen-thawed semen. The sperm characteristics of the semen samples of the 4 breeds recorded were ejaculate volume, ranging from 0.3±0.1 to 0.4±0.1ml, semen pH of 7.6±0.4 to 7.7±0.3, sperm motility (scale of 0-5) 2.8±0.8 to 3.1±0.9, estimated sperm motility 58.8±12.5 to 63.8±13.6%, ejaculate concentration (x109 sperm/ml) of 320.4±286.5 to 748.5±475.3, percentage live sperm 75.6±29.1 to 81.5±26.8%, and the percentage dead sperm 18.6±26.8 to 24.4±29.1% respectively, with the percentage normal sperm ranging between 77.3±17.1 and 84.8±9.0%. Head, mid-piece, tail and other sperm abnormalities of the fresh semen of the 4 breeds ranged from 2.9±3.3 to 7.7±9.6%, 7.9±5.2 to 11.0±7.0%, 0.4±0.8 to 1.9±3.0% and 0.6±0.9 to 1.5±1.9%, respectively. Semen samples were frozen in pellet form on a block of dry ice, by pipetting into the indentations on the surface of the ice. The frozen cockerel pellets were thawed following cryopreservation, by being placed into a test tube in a water bath (60°C), and the tube shaken continuously until complete thawing of the pellet. During the time of semen cryopreservation, a decrease in the number of live, morphologically normal sperm, and increase in the percentage dead sperm and sperm with abnormalities were recorded. The freeze-thawing process caused a significant (P<0.05) decrease in the percentage live sperm and the sperm motility, ranging between 37.4±10.4 and 42.3±12.1% and 3.6±0.5 and 3.9±0.3 respectively. A consequent increase in the percentage of dead sperm (between 57.7±12.1 and 62.4±10.8%) was also recorded. The sperm abnormalities regarding sperm head abnormalities ranged between 17.3±3.8 to 22.5±10.3%, the mid-piece abnormalities 7.9±3.8 to 10.4±2.0% and the tail abnormalities between 0.5±0.9 to 2.0±2.4% respectively for the thawed semen. Frozen-thawed semen was thawed in a water-bath 60°C and hens were inseminated twice per week using the frozen-thawed semen, and once a week with fresh semen for a total period of two weeks. Data for the two trials were analyzed using the ANOVA and the Tukey’s Studentized Range (HSD) test for repeated measures (SAS system General Linear Models Procedure). A total of 973 eggs, from all breeds of chicken namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn were collected following AI with fresh and frozen semen from individually caged hens. Eggs were collected, incubated and hatched to check if fertile and normal chicks could be produced from frozen-thawed cockerel semen. The difference in fertility and hatchability of the hens of the different breeds were compared and found to be highest in Rhode Island Red, White Leghorn, and Potchefstroom Koekoek respectively and lowest in New Hampshire using fresh semen. When using frozen-thawed semen, the sequence of fertility performance was the White Leghorn, Rhode Island Red, Potchefstroom Koekoek and New Hampshire, respectively. The effect of the numbers of sperm per AI dose on fertility, age at embryonic death, and hatchability of fertile eggs were also evaluated. Low numbers of sperm per AI in the hens resulted in a decrease in the total number of chicks hatched. The lowest fertility rate recorded was in the New Hampshire (2.7%), when using frozen-thawed semen to inseminate the hens. This may be attributed to the low numbers of sperm inseminated per AI dose. Egg hatchability of the fertile eggs was high in the White Leghorn (13.6%), Rhode Island Red (12.8 %), Potchefstroom Koekoek (9.7 %) and low in New Hampshire (2.7%) respectively, which could possibly be attributed to the egg size. Medium sized eggs were preferable for setting, in order to obtain an acceptable hatch, as they generally hatch better than the larger eggs. The results recorded for fertility and hatchability in the control group (fresh semen), was similar to the results recorded by other researchers, showing that the AI method used was acceptable. There still exists a necessity to develop an ideal cryopreservation method (diluent and freezing procedure), which would allow for acceptable long term storage of cockerel semen in liquid nitrogen (-196°C) for future use and export with minimum loss regarding sperm viability and fertilizing capacity.
Open Access
Characterization and cryopreservation of South African unimproved indigenous goat semen
(University of the Free State, 2010-05) Matshaba, Bright; Schwalbach, L. M. J.; Greyling, J. P. C.; Nedambale, T. L.
Semen from 7 South African unimproved indigenous bucks that were successfully trained from a group of 10 bucks for semen collection with the aid of an artificial vagina (AV) was characterized and then cryopreserved, using different semen extenders. Semen was collected twice a week and evaluated macroscopically for ejaculate volume and pH immediately after collection. Within 1h of collection, semen was further analysed electronically for sperm concentration. Thin semen smears were stained with eosin/nigrosin and evaluated under a fluorescent microscope for viability (percentage live or dead) and morphology (percentage normal or abnormal). In addition semen samples were evaluated using the computer assisted sperm analysis (CASA) for sperm motility (static, non progressive and progressive), velocities (static, slow, medium, rapid, VCL, VSL and VAP) and linearity (LIN, STR and WOB) parameters using a Sperm Class Analyser® (SCA®). Four different semen extenders, namely: Tris-1.5% yolk, Tris-15% BSA, Ovixcell® and Bioxcell® (IMV, L’Aigle, France) were used to cryopreserve pooled semen samples, with and without 6% glycerol thus making a total of 8 treatments. Immediately after dilution and after thawing, semen samples were compared through the evaluation of viability, morphology, motility, velocity and linearity parameters, using the same methodology used for fresh semen. Semen was then incubated at 37ºC and analysed for motility and velocity parameters after 30 and 60 minutes of incubation. Regarding the fresh semen samples, the South African unimproved indigenous bucks recorded an overall average ejaculate volume of 0.5 ± 0.2 ml, pH of 7.5 ± 0.2 and sperm concentration of 681.7 ± 74.6 x 106 sperm/ml. On average, bucks recorded 79.0 ± 6.3% normal and 76.3 ± 8.2% live sperm cells in the ejaculates. The average percentage of sperm abnormalities on head, mid-piece and tail were 4.2 ± 1.3%, 4.6 ± 1.7%, and 12.1 ± 5.4%, respectively. The overall sperm abnormalities recorded were 1.0 ± 0.8%, 9.5 ± 2.9% and 10.1 ± 3.6% for primary, secondary and tertiary abnormalities, respectively. The mean static, nonprogressively motile (NPM), progressively motile (PM), slow, medium and rapid sperm cells recorded were 30.9 ± 14.7%, 32.1 ± 10.9%, 37.3 ± 10.0%, 4.9 ± 1.7%, 6.0 ± 1.7% and 58.2 ± 14.1%, respectively. Viability of goat sperm following fresh semen dilution with the four different semen extenders was similar, however a reduction of approximately 20% in the percentage live and normal sperm was recorded (5-10 minutes after dilution), when compared to the fresh undiluted pooled semen sample. Similar motility parameters were recorded shortly after fresh semen dilution using the 4 different extenders. A slight decrease of approximately 4% in the extended semen’s sperm motility was observed, when compared to that of fresh undiluted semen. For the sperm velocity parameters, semen extended in Tris-BSA showed significantly higher medium sperm velocity. Following freezing-thawing, a drastic reduction in the percentage live and normal sperm was recorded in all treatments. Bioxcell® without glycerol recorded the highest number of live and normal sperm. The Bioxcell® and Ovixcell® extenders recorded the highest percentage linearity and straightness movement of the sperm. In general, cryopreservation reduced the sperm cell viability and motility parameters. In addition no effect of extender on the morphology of South African unimproved indigenous buck sperm was observed. Sperm motility and velocity results showed that sperm extended in Bioxcell® and Ovixcell® recorded higher values immediately post-thawing, while the Tris-based extenders recorded the highest values after 30 minutes of incubation, before declining rapidly. The South African unimproved indigenous bucks seem to produce a lower semen volume (ejaculate), sperm concentration, and percentage progressively motile sperms, compared to the European, Asian and Boer goat breeds. The results demonstrate that Bioxcell and Ovixcell are suitable extenders to induce high post-thawing viability, motility and velocity of buck sperm.
Open Access
Characterization of breed additive and heterosis effects in beef cattle using experimental results
(University of the Free State, 2011-09) Theunissen, Anette; Scholtz, M. M.; MacNeil, M. D.; Neser, F. W. C.
The objective of this study was to infer direct and maternal additive effects and direct and maternal heterosis effects for growth, fitness and carcass traits in beef cattle using least squares means estimated from crossbreeding studies by Els (1988) and De Bruyn (1991). The dataset was formed by recording each least squares mean along with the breed composition, maternal breed composition and direct and maternal heterozygosity. Each trait was analyzed using a single trait fixed effect model which included source of data as a fixed effect and breed composition and heterozygosity as covariates. Breed solutions were relative to the Afrikaner breed. Heterosis results were also obtained for crosses not made. Among breed groups, crossbred calves showed higher average values for almost all traits than purebred calves. The average direct heterosis contributions to weight traits in ten two-breed genotypes, which involved the Afrikaner (A) as dam line and the Simmentaler (S), Brahman (B), Charolais (C) and Herefords (H) as sire lines were 3.5, 7.9, 8.2 and 4.3% for birth weight (BW), weaning weight (WW), 19-month heifer weight (HW) and cow weight at partus (CW) respectively. Similarly, the average maternal heterosis effects for the weight traits in the four A crossbred dam genotypes (BA, CA, HA and SA) were 1.5, 8.8, 4.9 and 2.9% for the growth traits respectively. Due to additive and non-additive effects of C and B purebreds on BW these sires should only be bred to mature cows. For a weaner calf production system, the C genotype had the highest direct breed effect of +64.1 kg or 34.8% for WW. The combined additive effect of the C dam line was however, exceeded by the S dam line (+38.4 kg or +20.9% versus +50.0 kg or +27.2%). The total combined heterosis effect of the CA dam line was +32.5 kg versus the +19.2 kg effect of the SA dam line. The average expected phenotypic values for WW for the SA dam line was thus larger than the CA dam line (233.3 versus 230.7 kg). The maternal heterosis effect of the HA dam was the second largest (+22.1 kg) of the four two-breed combinations of A. The B genotype used in the study did not have a true superior ability to increase the expected WW in the A breed. The direct and maternal heterosis effects of the breed were - 0.5 kg or -0.3% and +22.1 kg or 12.0% respectively. The H breed had the lowest direct breed effects of +24.7 kg or +13.4% on WW out of the four purebred sire lines that were bred to the A dam line and a small negative direct heterosis effect (-0.5 kg or -0.3%). Furthermore, the maternal additive effect was negative (-29.6 kg or -16.1%). The maternal heterosis effect however, was positive (+22.1 kg or +12.0%). The A sire line had the lowest expected phenotypic values for HW and CW (323.9 and 434.3 kg respectively), indicating that these heifers would probably reach puberty earlier and that these cows would be smaller compared to genotypes from S, B, C and H genotypes. On average two-breed genotypes had 48.9 and 40.6 kg expected increase in HW and CW respectively, and an additional 21.9 kg and 20.4 kg for the two traits respectively in threebreed genotypes (backcrossing excluded). The H sire line did not have a true ability to increase expected CW in the A breed. The C genotypes had the lowest average individual heterosis effect of -17.6 kg (-4.0%) on CW of all four sire lines which were involved in the ten different two-breed combinations of the study. However, the CA dam line was responsible for the highest maternal heterosis effect of +54.8 kg or +12.6% out of the four crossbred A dam lines. By utilizing genotypic differences the opportunity for high productivity and profitability can be maximized, especially through cumulative traits such as the calf/cow weight ratio. All crossbred genotypes, except the BA genotype, increased the calf/cow weight ratio. Results indicated that the A breed should constitute 75% of the genetic make up of B and C crossbred genotypes and 25% of H and S crossbred genotypes to maximize calf/cow weight ratios. The HSA, HBA and BSA, genotypes had the largest calf/cow weight ratios of 0.509, 0.506 and 0.495 respectively, mainly due to the large direct heterosis effects of +22.7 (+12.3%), +28.0 (+15.2%) and +36.7 kg (+19.9%) of the HS, HB and BS genotypes for WW respectively. This gives opportunity for direct paternal heterosis to be used in crossbreeding systems with purebred A dams. Alternatively, since the B breed had a true ability to increase the expected BW in the A dam, it is suggested that a specific or rotational crossbreeding system which involves S and A dams that are mated with either H or B (only on mature dams) sires for the production of weaner calves under sweet veld conditions, be used. The data were also used to estimate the additive and non-additive effects for fitness traits in the two- and three-breed crosses. The average direct heterosis contributions were +14.9, +109.1, -162.7, +21.0 and 15.4% respectively for CR, MB, MP, WP and WR for ten two breed genotypes. Similarly, the average maternal heterosis effects in four A crossbred dam genotypes were 0.0, -87.5, +97.7, -1.9 and -7.4% for the fitness traits respectively. The HA genotype had the highest expected F of 83.1% in two-breed genotypes. The direct heterosis contributions in the HA genotype were +21.7, -2.3, -5.8, +28.3 and +30.1% percentage units respectively and the maternal contributions were -8.2, -2.4, +1.6, -6.4 and -11.6 for the traits respectively. The expected phenotypic values for improved traits in the HA and AHA genotypes were 94.9 versus 96.4% for CR, 92.2 versus 96.3% for WP and 83.1 versus 86.8% for WR (MB and MW remained unchanged). Crossbreeding the A dam line with the B sire line resulted in improved expected WR: 66.7 versus 80.2% in BA. Backcrossing the BA genotype decreased WR. This could mainly be explained by the increased expected MW; 3.3% in the A versus 6.0 and 15.6% in the BA and ABA genotypes respectively and the lower expected WR of 72.8 and 74.5% in the ABA and BBA genotypes respectively. While the SA genotype had an improved expected WR of 78.4% compared to the A genotype (66.7%), the WR in the ASA progeny was the lowest of all genotypes (60.4%). The low expected WR of the SA genotype could be explained by the increased expected MB of 5.3 versus 2.2% and MW 5.7 versus 3.3% of the A breed. The poor performance of the SSA genotype could be ascribed to an increase in MB and MW which was 7.3 and 4.3% respectively. The ACA, AHA and BHA genotypes had the highest expected WR of 86.9, 86.8 and 83.0% respectively. A specific crossbreeding combined with a terminal sire system is suggested to increase fertility in the A breed. Rotational systems will not have the same advantage since backcrossing the CA or HA dams to their respective sire lines would decrease the WR to 64.2 and 73.1% respectively. Alternatively, CA, HA or CH crossbred sires could be used on purebred A dams in a specific crossbreeding system. These genotypes had the largest direct heterosis effect on WR of all ten two-breed genotypes (36.5, 30.1 and 30.8% percentage units respectively). In a specific two-breed system the HA genotype would maximize WR. Although the average direct heterosis effects were unfavourable (-2.1 and -13.0 g/day respectively) for feedlot gain (FG) and carcass gain CG), feed conversion ratio (FCR) was -2.3% (a desirable effect). The average maternal heterosis effects for the feedlot traits were undesirable in the four A crossbred dam genotypes (-1.3, -7.4, and +0.9% respectively) for all the traits. Although these average heterosis effects suggest that feedlot traits do not benefit from crossbreeding, selected genotypes offer opportunity to increase feedlot production efficiency. As purebred the A compared less favourably in feedlot traits with Bos taurus breeds. However, it was evident that the A dam in two-breed crossbreeding could outperform the purebred S and Bos taurus crossbred dam lines in most of the these traits. The average direct heterosis contributions to feedlot traits in ten two-breed genotypes for the S, B, C and H as sire lines were -2.1, -13.0 (undesirable) and -2.3% (desirable) for feedlot gain (FG), carcass gain (CG) and feed conversion rate (FCR) respectively. Similarly, the average maternal heterosis effects for the feedlot traits in the four A crossbred dam genotypes were -1.3, -7.4, and +0.9% (undesirable) for FG, CG and FCR respectively. However, the A dam could be utilized in two-way crossbreeding systems with a terminal sire such as the C. The CCA genotype had expected average FG, CG and FCR of 1376.8 g/day, 781.2 g/day and 6.0 kg/kg respectively. Alternatively, the paternal heterosis contributions from BA, HA, SA, BH, BS and HS sire lines were also favourable. The aforementioned genotypes could thus be used as sire lines on purebred A dams to improve feedlot traits. It should however be noted that the data did not take cogniance of the genetic trends in the traits and the effects on heterosis parameters in any of the breeds since the conduction of the crossbreeding experiments. Heterosis units are therefore not directly applicable.
Open Access
Cryopreservation of South African indigenous ram semen
(University of the Free State, 2012-05) Munyai, Pfananani Hendrick; Nedambale, T. L.; Greyling, J. P. C.; Schwalbach, L. M. J.
Semen was collected from the indigenous Damara, Namaqua Afrikaner, Pedi and Zulu rams. Hundred and twenty eight (128) ejaculates were collected throughout the entire study, with semen being collected twice a week (every Monday and Tuesday) from each ram, using the electro-ejaculator. Ejaculates were collected in graduated test tubes, placed in a thermo flask at 37°C, and transported to the laboratory for evaluation within 1h interval. The raw or fresh undiluted semen was then microscopically evaluated for volume, concentration, pH and sperm motility. The sperm concentration was determined with the aid of a spectrophotometer (Spermacue®) and the semen pH using a pH meter (Microprocessor pH/mV/°C Meter Hanna HI 931401). A Computer Assisted Sperm Analysis (CASA) system was used to evaluate the different sperm motility characteristics. All data were analysed using the statistical GenStat® program. The analysis of variance (ANOVA) was used to test for significant differences between treatments. Characterization of the South African indigenous ram sperm viability (percentage live/dead) of the semen samples was determined, using an eosin/nigrosin stain (60μl eosin/nigrosin and 6μl semen), in a thin smear. All sperm cells were evaluated on the same day of semen collection with the aid of a fluorescent microscope (BX 51TF), using an oil immersion objective (X100 magnification). The live sperm fluoresced green, while the dead cells stained red. The live sperm cells were further categorized as morphologically normal or abnormal. The volume of the indigenous ram ejaculates ranged between 0.4 and 0.9mL. The sperm concentration recorded in this study ranged between 0.9 and 1.3x109 sperm/mL, which are much lower when compared to other studies. The semen pH recorded in this study ranged between 6.5 and 7.3 and the sperm abnormalities ranged between 5.2% and 8.2% – which is regarded as acceptable for fertilization. To test the effect of storage temperatures on the viability of the diluted ram semen stored for different periods of time, the same procedure of semen collection and semen evaluation was followed. After the initial semen evaluation, all semen samples were pooled and diluted equally in an egg yolk citrate extender in the ratio of 1:1(v/v). The pooled semen sample was then divided into two portions, one sample being stored at 5ºC, and the other at 15°C, following storage periods of 3, 6, 9, and 24h respectively. Sperm characteristics were then recorded for each interval of storage. In general the percentage total motile sperm recorded after a 24h period of storage at 15°C was higher (61.2%), compared to that at 3h (51.4%), 6h (50.1%) and 9h (50.6%). From the results of this study it was concluded that diluted ram semen can be successfully stored for 24h at 15°C, retaining sperm motility for the application of AI. When evaluating the effect of glycerol as a cryoprotectant, in the diluted ram semen stored at two temperatures for different periods of time, the same procedure for semen collection and evaluation was followed. After initial evaluation, all semen samples were pooled and diluted equally with an egg yolk citrate extender containing 14% glycerol in the ratio of 1:1 (v/v), resulting in a final glycerol concentration of 7%. The pooled semen sample was then divided into two portions, one sample being stored at 5ºC and the other at 15°C, for periods of 3, 6, 9, and 24h. Sperm characteristics were recorded at each interval of semen storage. Semen stored at 15°C recorded a 48.3% total motile sperm after 3h of storage, but this increased to 50.4% following 24h of storage. The percentage of total motile sperm remained relatively constant at 40% after 3h of storage and 40.8% after 24h in the semen stored at 5°C. The addition of glycerol as a cryoprotectant demonstrated a protective effect on the sperm motility characteristics of sperm stored at both 5°C and 15°C for up to 24h of storage. The effect of different glycerol inclusion levels in the diluent, on the indigenous ram semen characteristics following cryopreservation were evaluated. The same procedure for semen collection was followed and semen was subjected to the initial evaluation comprising sperm concentration, semen pH and sperm motility. After initial evaluation of the ejaculates, the semen samples were diluted with an egg yolk citrate extender (EYC) fraction A (without glycerol), in the ratio of 1:1 (v/v) and cooled over a period of 2h to 5°C. All ram ejaculates were pooled and then divided into 4 portions treatment (groups). The first group was diluted with EYC (fraction A), which served as a control and the other 3 groups with EYC (fraction B) contained 7, 10 or 14% glycerol (GLY) in the ratio of 2:1 (v/v), making final glycerol concentrations of 2.3, 3.3 or 4.7% respectively. The semen samples were equilibrated for 2h and then loaded into 0.25mL semen straws. The straws were frozen in liquid nitrogen (LN2) vapour, whereafter semen straws were plunged into the LN2 (-196°C). The semen straws were thawed 7 days later, in a water bath (37°C) for 30 seconds. The sperm characteristics (motility and velocity) were microscopically evaluated using the Sperm Class Analyzer® (CASA) system. A 10% glycerol inclusion rate recorded a higher percentage of total motile sperm (15.6%), compared to the 7% glycerol (12.8%) and 14% glycerol (8.5%) inclusion levels, although all these differences were not significant. This study demonstrated that an egg yolk- citrate extender containing 10% glycerol can be used to cryopreserve indigenous ram semen effectively, based on the sperm motility characteristics. The low sperm motility results recorded when semen was cryopreserved in an extender containing 14% glycerol also indicated a degree of toxicity of glycerol at high inclusion levels in the semen extender. Regarding the conventional slow cryopreservation (programmable freezer) of ram semen versus semen cryopreservation in liquid nitrogen vapour, the same procedure for semen collection and evaluation was followed. After the initial evaluation of the raw semen samples, all ejaculates were pooled and then diluted using an egg yolk - citrate extender (EYC) fraction A (without glycerol), in the ratio of 1:1(v/v) and cooled over a 2h period at 5°C. After equilibration, the pooled semen sample was further diluted with EYC fraction B, containing 14% glycerol, in a ratio of 2:1(v/v)resulting in a final glycerol concentration of 4.7%. The pooled semen sample was then further equilibrated and loaded into 0.25mL semen straws. Half of the straws were frozen in liquid nitrogen (LN2) vapour and then plunged into the LN2. The other half of the semen straws were frozen with the aid of a programmable freezer. After 7 days, the semen straws were thawed in a water bath at 37°C, for 30 seconds. The sperm characteristics (sperm motility and velocity) were microscopically evaluated using the CASA system. From the findings in this study, it can be concluded that a controlled rate of semen cooling gave superior sperm motility results (15.3±3.0%), compared to semen frozen in LN2 vapour (8.8±0.9%). It should be noted that programmable freezers are costly, when compared to the liquid nitrogen vapour technique. Due to the fact that sperm motility differences recorded were not significant, it is suggested that the freezing of semen on a small scale be done using the LN2 vapour technique, without any significant decrease in sperm motility or possible fertility.
Open Access
The degradable protein requirements of beef cattle consuming winter forage hay from the pure grassveld type
(University of the Free State, 2010-05) Bareki, Mathuto Abigail; Van der Merwe, H. J.; De Brouwer, C. H. M.; Ferreira, A. V.
A trial was conducted to determine the total rumen degradable protein intake (RDPI) required to maximise the digestible organic matter intake (DOMI) of beef cows consuming low quality grass hay from the Northern variation of Cymbopogon-Themeda pasture type (pure grassveld). Thirty five pregnant Afrikaner x Simmentaler crossbred cows (±517.08kg, SD 53.06) were randomly allocated to 5 treatments. Treatments provided the following RDP levels/cow/day 0g, 180g, 360g, 540g and 720g. A RDP source, calcium caseinate (90% crude protein (CP) on dry matter basis and 100% rumen degradable) was used and mixed with molasses based concentrate. The cows had ad lib access to low quality grass hay (2.26% CP, 73.94% neutral detergent fibre). The trial period consisted of 14 days adaptation, 21 days intake study and 7 days digestibility study. No statistical significant (P > 0.05) influence of RDP level on the apparent digestibility of dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF) was detected. The grass DM intake (DMI), DOMI and metabolisable energy intake (MEI) increased in a linear and quadratic manner (P < 0.05) with increasing levels of supplemental RDP. The single broken-line model predicted DOMI/kg BW0.75 with higher accuracy (R2 = 0.45) than the quadratic regression procedure (R2 = 0.07). According to this model 4.03g daily RDPI/kg BW0.75 or 8.07% RDP of DOM was required to maximise DOMI of pregnant beef cows consuming winter grassveld hay. In a second trial the potential to substitute true protein with urea was investigated. Urea replaced 0%, 25%, 50%, 75% and 100% of the natural supplemental RDP. The same procedure as described in the first trial was followed. The increasing proportion of urea did not significantly (P > 0.05) influence the apparent digestibility of DM, OM and NDF. There was a linear increase in grass DMI (P = 0.0355) at increasing levels of urea, with the highest intake observed when urea was used as a sole source of nitrogen (N). DOMI and MEI increased in both linear and a quadratic manner (P < 0.05) with increasing levels of urea. The molar proportions of acetic, propionic and butyric acid were not affected (P < 0.05) by the substitution of urea, while the molar percentages of iso-butyric and iso-valeric acid were significantly decreased (P < 0.0001) with increasing urea levels. Ammonia N increased linearly (P = 0.0426) while the ruminal pH was not affected (P > 0.05) by increasing the proportion of urea. It seems that urea can be the sole RDP source in supplements for pregnant beef cows consuming the low quality grass hay. In the third trial, the influence of replacing natural protein with urea on the performance of beef cows grazing natural winter grassveld was investigated. Pregnant Afrikaner x Simmentaler crossbred cows were randomly allocated to the two treatments. The number of cows per treatment varied between 18 and 28 each year. The trial was executed over four consecutive winter periods from 2003 to 2006. The treatment licks comprised of: 1) 100% supplemental RDP from urea and 2) 50% supplemental RDP from urea and 50% from cottonseed oilcake. Lick provision was controlled to ensure the total RDPI as recommended in the first trial. Increasing the proportion of supplemental RDP from urea did not have a significant (P = 0.9938) effect on the end live mass of the cows. The urea levels did not significantly influence (P > 0.05) weaning mass, corrected weaning mass and average daily gain of the calves. The lack of significant lick treatment effect on live mass, body condition score and performance of the calves suggests that urea can be used as a sole source of RDP.
Open Access
Determination of some blood parameters in the African lion (Panthera leo)
(University of the Free State, 2008-11) Erasmus, Heidi Louise; Schwalbach, L. M. J.; De Waal, H. O.
The goal of this study was to generate a database of laboratory results for African lion (Panthera leo) blood to obtain reliable reference ranges to augment what is currently available in literature. Also to investigate the possibility of age and sex having an influence on these reference ranges. The specific objectives of this study were: o to determine reference values for haematological and biochemical blood variables for lions bred in captivity, as a function of age and sex; o to evaluate the Beckman Coulter Ac•T 5diff Haematology Analyzer for lion differential white blood cell analyses; o to determine morphometric measurements and establish reference growth curves (and range reference values) for lions bred and reared in captivity as a function of age and sex; o to determine reference values for some practical and meaningful body measurements and their correlations. This study was conducted on three lion ranches in the Free State province and at the Bloemfontein Zoological Gardens (Bloemfontein Zoo) with captive lions (Panthera leo) of both sexes and ages ranging from three months to nine years. Lions were divided into four age groups according to published literature. Animals were chemically immobilized (darted) with Zoletil® 100 at 4 to 5mg/kg in their holding camps and moved to a shaded place as soon as the drug had taken its full effect. Blood was collected into three different types of blood collection tubes and body measurements were taken. This was all done as fast as possible before the effect of the immobilizing drug could wear off. In some cases it was necessary to give an animal a top-up dose to prevent it from waking up too quickly. Animals were moved back to their holding camps to fully recover from the immobilization. Blood analyses done with the Ac•T 5diff Haematology Analyzer from Beckman Coulter® for haematological parameters was conducted within 30 minutes after blood collection. Blood for biochemistry parameters was centrifuged, serum collected and cryo preserved at -20°C until it could be taken to the laboratory for analyses. Blood smears were made on the lion ranches and Bloemfontein zoo immediately after the analysis with the Ac•T 5diff Haematology Analyzer, fixed and packed for transport to the laboratory. At the laboratory the serum was used for biochemistry analyses, using standard laboratory techniques. Blood smears were stained and examined under a light microscope for the differential white blood cell count by means of the manual-visual method. Results were statistically analyzed to determine reference ranges and the influence of age and sex on these reference range values for the different parameters, were considered. Body measurement were also statistically analyzed to determine correlations between body weight and different other measurements. These correlations were then used to determine if it will be possible in a field situation to use the age and sex of an animal together with a certain body measurement to estimate body weight accurately, if actual weighing was not possible. From these analyses it was concluded that age and sex do have an influence on blood analysis and blood reference ranges for the African lion (Panthera leo). Unfortunately, it differs between parameters and there is not one rule to apply. The conclusion could also be made that body weight could be determined by measuring the head length of an animal. More research is warranted to obtain more data set and establish range reference values that can be validated and used with a high degree of confidence in the lion breeding industry.
Open Access
Dietary fibre requirements of feedlot lambs
(University of the Free State, 2008-05) Smith, Pieter Schalk; Van der Merwe, H. J.; Ferreira, A. V.
No abstract available
Open Access
Die doeltreffendheid van proteïen- en energiebenutting deur vleisvarke
(University of the Free State, 1972) Smith, Gerhardus Adam; Van der Westhuizen, A. A.
Abstract not available
Open Access
The ecological planning of Doornkloof Nature Reserve, Northern Cape Province
(University of the Free State, 2014-01) Smit, Zacharias Martinus; Smit, G. N.; Du Preez, P. J.
The successful and effective management of conservation areas can only be achieved with access to sound environmental data. The Doornkloof Nature Reserve (DNR) in the Northern Cape Province, was in need of such data which was essential for the development of proper management policies. The objectives of this study were to identify, describe and measure the most important environmental characteristics of the reserve, which will be used as the baseline data for the refinement of management policies. This included the identification and description of the plant communities; the demarcation of management units; determining the botanical composition and the veld condition of each management unit; quantifying the density; species composition and above-ground biomass of woody plants; calculating the carrying capacity (graze and browse); determining the seasonal habitat selection, group sizes and social structures of the ungulate species of DNR and developing a suitability index to assists management decisions. The Braun-Blanquet method was used to identify the plant communities of DNR. A total of 204 reléves were sampled and upon analysis six major plant communities and 14 sub-communities were identified. The plant communities and sub-communities were grouped into seven management units. Due to the heterogeneous landscape of the reserve, the vegetation of DNR was relatively diverse, consisting of grasslands, shrublands and riverine communities. A step point-method and the Ecological Index Method were used to determine the species composition and veld condition of the herbaceous layer of each management unit respectively. The grazing capacity of each management unit was determined by two separate methods. The floristic diversity differed substantially between topographical features, rather than between management units. The mountainous areas were in excellent veld condition and had a high grazing capacity, while the more degraded lower regions were in poor to good condition and had substantially lower grazing capacities. Rainfall and grazing played an important role in the study area and indicated that the vegetation of Doornkloof Nature Reserve displays both equilibrial and non-equilibrial trends. A quantitative description technique, (BECVOL3-model), was used to quantify the plant densities, species composition and above ground biomass of the woody plants of each management unit. Browsing capacities were calculated for different browsing heights (1.5m, 2m and 5m). Both plant densities and browsing capacities differed substantially between the various units. Plant densities varied from 40 plants/ha to 1 120 plants/ha, while browsing capacity varied from 4 ha/Bu to 157 ha/BU at a browsing height of 2 m. The browsing capacity did not decline substantially from the wet to the dry season, predominantly due to the abundance of evergreen species. The habitat selection of seven ungulate species was investigated by recording sightings of game species within each habitat unit. A goodness-of-fit test was applied to the data to determine if habitat selection of game species differed from being random. Habitat selection was found not to be random. Confidence intervals were calculated by means of the Bonferroni method to determine the habitat preference of each game species. The results indicated that species had clear habitat preferences and that some species showed seasonal changes in habitat selection. Species such as buffalo and mountain reedbuck were found to be habitat specialists, while species such as eland were more habitat generalist. The results indicated that eland, kudu and warthog were thriving in the environment, while the gemsbok and mountain reedbuck population were not adapting as well as expected. An alternative approach to conventional habitat suitability models was attempted in this study. The proposed suitability model proved to be relatively accurate in predicting both the habitat selection of game species and the quality of the habitats of DNR. The potential use of similar suitability models holds potential as a tool in assisting with objective management decisions
Open Access
The effect of Coryne bacterium cutis lysate to control somatic cell counts in dairy cows
(University of the Free State, 2011-09-20) Pretorius, Christa; Schwalbach, L. M. J.; Greyling, J. P. C.
English: The main aim of this study was to evaluate the effectiveness of repeated inoculations of a Corynebacterium cutis lysate (Ultra-Corn®) - a non-specific immune-stimulant, to reduce the milk SCC in commercial dairy cows. An additional aim was to evaluate if these inoculations had any detrimental effects on milk quality. This study was performed in two separate trials, using Holstein cows with SCC’s over 250 000 cells/ml of milk at different stages of lactation from two commercial dairy farms in the Free State Province. On each farm, cows were paired according days in milk and SCC, in order to obtain two homogeneous groups of experimental animals. The two groups of cows in each farm were randomly allocated to a treatment or a control group. Both groups in the same farm were managed under the same conditions for the entire trial periods. The only difference was that cows from the treatment group received 3 weekly inoculations of Corynebacterium cutis lysate(Ultra-Corn® ), while those from the control group received distilled water for injection (the same volume as the cows in the treatment group). Two similar trials were conducted, using the same basic experimental design. Differences were only in the dose of the Corynebacterium cutis lysate inoculated per cow treated, number of experimental animals and duration of the observation periods. In Trial 1, cows from the treated group received 3 weekly vaccinations of Ultra-Corn® (4 ml per cow, thus 80mg of Corynebacterium cutis lysate per cow) injected subcutaneously (sc), while those from the control group received 3 weekly sc injections of 4 ml distilled water. This was followed by 8 weeks of observation of the effect of treatment on milk SCC and composition. In Trial 2, the three doses of Corynebacterium cutis lysate administered weekly per cow for the treated group was 2ml/100kg, thus 40mg Corynebacterium cutis lysate/100 kg per cow. This was followed by 8 weeks of observation of the effect of treatment on milk SCC and composition. Individual quarter milk samples were collected weekly from all cows and analysed for SCC and a combined milk sample (from the measuring bottle in the milk parlour) from each cow was also taken for butterfat, protein, lactose and urea content. The results were compared between the two groups per farm, using ANOVA procedures for repeated measures analysis, using the 95% confidence level (SAS, 2004). The two farms were evaluated separately, due to the possible differences between general management conditions, which could introduce serious confounding factors if the results from the two farms were combined. However, it can be considered that both dairy farms used an acceptable level of commercial dairy management practices and produced an acceptable yield per cow under South African commercial conditions. In general no significant differences were recorded between the treated and control groups of cows in both farms in both trials in terms of milk SCC, butterfat, protein, lactose and urea content of the milk. In this study, the immuno-stimulant effect of Ultra-Corn®, a Corynebacterium cutis lysate could not be confirmed in lactating cows. Although this inoculant does not seem to have any detrimental effects on the main solids of the milk, its use cannot be justified as it did not significantly reduce somatic cell counts in lactating cows. Further research is warranted to develop and evaluate the effectiveness of vaccines against mastitis causing organisms, in order to control SCC and mastitis in dairy cows. However, when such studies are conducted it is advisable to use very high number of experimental units and proper control trials should be conducted. All efforts should be done to ensure minimum environmental changes during these trials, which can introduce serious confounding effects in the experimental design.
Open Access
The effect of dietary lipid saturation and antioxidant sources on performance and meat quality of lambs
(University of the Free State, 2014-05-27) Booyens, Käte Erna; Einkamerer, O. B.; Hugo, A.; Van Der Merwe, H. J.
English: A study was conducted to investigate the influence of antioxidant source and fatty acid saturation in a standard finishing diet on apparent digestibility, production performance, fatty acid composition and oxidative stability of lamb. The four dietary treatments consisted of the same basal diet (187 g CP- and 355 g NDF/kg DM) differing in the lipid source (30 g/kg of either saturated beef tallow or unsaturated soyabean oil) and type of antioxidant included (125 g/ton of either a synthetic or natural antioxidant). Eighty-four S.A. Mutton Merino lambs (27.64 ± 1.72 kg) were randomly allocated to the four dietary treatments (n=21 lambs per treatment) and subdivided into seven replicates per treatment (n=3 lambs per replicate). After dietary adaptation of 8 days all lambs received the experimental diets for the remaining period (41 days). A digestibility study was conducted over a 12-day period (4-day adaptation to the faecal bags followed by an 8-day collection period). Seven lambs per treatment were randomly selected and slaughtered at completion of the production study. Physical carcass characteristics, muscle pH, muscle- and subcutaneous fatty acid composition, as well as meat oxidative- (malonaldehyde content) and colour stability was measured. The apparent NDF digestibility was reduced (P =0.0548) with the inclusion of unsaturated soyabean oil in the diet compared to saturated beef tallow. This was associated with a significant (P <0.05) lower digestible NDF and ME content in the experimental diet. No significant (P >0.05) differences in dry matter intake, daily gain and feed efficiency of lambs occurred. The addition of unsaturated soyabean oil significantly increased (P =0.0003) the efficiency of ME utilisation in the diet. Lipid saturation level in finishing diets for lambs did not influence (P >0.05) the physical carcass characteristics and meat pH of lambs. Saturated beef tallow increased (P <0.05) the monounsaturated palmitoleic- and oleic acid content of lamb subcutaneous and/or muscle tissue, whereas the more unsaturated soyabean oil increased (P <0.05) the polyunsaturated linoleic acid, α-linolenic acid and CLA content of both muscle fat and subcutaneous lipid tissue. Monounsaturated vaccenic acid was increased in lamb meat when unsaturated soyabean oil was included in combination with the natural antioxidant. The total PUFA, total n-6 fatty acid and PUFA:SFA ratio of lamb meat increased (P <0.05) with the inclusion of the more unsaturated soyabean oil in the diet. A higher (P <0.0001) n-6:n-3 ratio occurred in the intramuscular fat of lambs fed the unsaturated soyabean oil diet. Unsaturated soyabean oil negatively influenced (P <0.05) the oxidative stability of lamb meat on days 0 (fresh) and 90 (frozen), compared to saturated tallow. The inclusion of a synthetic compared to a natural antioxidant in the diet decreased (P =0.0672) the apparent digestibility of NDF, which was also associated with a significantly (P =0.0159) lower digestible NDF content of the experimental diet. The meat pH measured 45 minutes after slaughter was significantly (P =0.009) decreased when a synthetic antioxidant was added to the diet. Meat pH measured at 24 hours post slaughter was lower (P =0.0433) when a natural antioxidant was added to the diet. With the exception of the natural antioxidant that increased (P <0.05) the saturated palmitic- and monounsaturated palmitoleic acid content of subcutaneous and/or muscle fat, and decreased (P <0.05) the monounsaturated stearic acid content of intramuscular fat, dietary antioxidant type did not to effect (P >0.05) the fatty acid composition of lamb meat, neither the colour- nor oxidative stability. These results suggest that the fatty acid profile of lamb can be manipulated by the saturation level of the lipid source included in the diet. However, the replacement of saturated tallow with unsaturated soyabean oil did not result, from a human health point of view, in the desirable PUFA:SFA and n-6:n-3 ratios in muscle fat and subcutaneous lipid tissue. Therefore, the manipulation of the fatty acid content of finishing diets to achieve the desirable ratios within lamb meat, as well as the optimal inclusion level of a bioflavonoid antioxidant warrants further research.
Open Access
Effect of dietary lipid saturation on layer production and egg quality
(University of the Free State, 2012-07) King, Ernest John; De Witt, F. H.; Van der Merwe, H. J.; Hugo, A.
English: A study was conducted to investigate the effects of dietary lipid saturation on nutrient digestibility, egg production and egg quality characteristics of laying hens during peak production (≤ 42 weeks of age). Five isoenergetic (12.6 MJ AME/kg DM) and isonitrogenous (170 g CP/kg DM) diets were formulated with a 30 g/kg lipid inclusion level, using a blend (50 / 50) of fish- and linseed oil (control n-3), pure fish oil (polyunsaturated n- 3), sunflower oil (polyunsaturated n-6), high oleic acid (HO) sunflower oil (monounsaturated n-9) and tallow (saturated fatty acid treatment). The blend of fish- and linseed oil blend were used to increase the α-linolenic acid content of the control n-3 diet, while fish oil was used in the polyunsaturated n-3 diet to increase the concentration of eicosopentaenoic- (EPA) and docosahexanoic acid (DHA) fatty acids primarily. Sunflower oil and HO sunflower oil was used to increase the linoleic- and oleic acid in the polyunsaturated n-6 and monounsaturated n-9 diets respectively, whereas tallow was used to increase palmitic- and stearic acid levels in the saturated fatty acid (SFA) treatment. Two hundred, individually caged Hy-Line Silver Brown hens (20 weeks of age) were randomly allocated to the five dietary treatments (n = 40 replicates/treatment) and received the respective experimental diets. During 24, 28, 32, 36 and 40 weeks of age, all eggs produced were recorded, individually weighed and used for analysis of internal and external egg qualities. While feed intake of hens was measured weekly, body weights were determined monthly. Data for the respective collection weeks were pooled for calculation of parameter means during statistical analysis. During the mentioned weeks eggs were evaluated for shell quality and internal egg quality. During week 30 of age, 12 eggs per treatment were also randomly selected for analyses of fatty acid methyl esters (FAME), thiobarbituric acid reactive substances (TBARS) and peroxide value (PV) while another 12 eggs were stored at 4oC for analyses after 28 days. At the end of the study (42 weeks of age) six birds per treatment were used to determine the effects of dietary lipid saturation on nutrient digestibility. Dietary lipid saturation had no effect (P > 0.05) on feed intake as well as most of the nutrient digestibility coefficients, except in the case of crude protein (P < 0.05) and fat (P < 0.0001), whereby the monounsaturated n-9 diet resulted in the highest (P < 0.05) CP digestibility which differs statistically only with that of the polyunsaturated n-6 diet, but not with any of the other dietary treatments. Therefore, no clear influence of dietary lipid saturation on apparent digestibility of CP could be detected. Furthermore, all poly- and monounsaturated diets had a higher fat digestibility (94.2 to 95.6%) than the SFA diet (90.4%). Although both the polyunsaturated n-6 and control n-3 treatments had the lowest (P < 0.01) apparent metabolisable energy (AME) and AME corrected for nitrogen (AMEn) values, no clear trend regarding dietary lipid saturation on nutrient digestibility could be established. Similarly to nutrient digestibility results, dietary lipid saturation resulted in a limited significant response on production parameters tested without any recognisable trends. The SFA treatment resulted in the lowest (P < 0.015) percentage sellable eggs, while feed efficiency (P < 0.001) and percentage eggshell (P < 0.05) was the lowest for the monounsaturated n-9 and polyunsaturated n-6 treatments respectively. Evaluating internal egg qualities, the control n-3 and polyunsaturated n-3 treatments had the lowest (P < 0.0001) egg yolk colour compared to that of the SFA which resulted in the highest colour score. Additionally, the FAME of egg yolk was successfully altered to represent that of the particular dietary treatment without any detrimental effects on the total fat content (P = 0.24), fat free dry matter (P = 0.17) or moisture (P = 0.66) content of egg yolk. The polyunsaturated n-3 treatment was highly effective (P < 0.0001) in increasing the EPA and DHA concentration of egg yolk, whereas a general increase in the dietary n-3 content resulted in a decreased (P < 0.0001) ratio of n-6 / n-3 for both the control n-3 and polyunsaturated n-3 diets. Both the SFA and monounsaturated n-9 treatments resulted in the lowest (P < 0.0001) TBARS for both time periods, whereas the polyunsaturated n-3 treatment resulted in the highest (P < 0.001) TBARS for both fresh and stored eggs (0.27 mg malonaldehyde / kg yolk during both time periods). From the results of the current study it can be concluded that although fat digestion was lower for the SFA treatment, AME values did not differ between treatments. With the exception of the SFA treatment that resulted in less sellable eggs, no influence of lipid saturation on egg production and external egg shell qualities could be detected. The results showed that PUFA n-3 diets could be successfully used to enrich the essential n-3 fatty acids of eggs. However, lipid oxidation stability as well as yolk colour was negatively influenced by an increase in PUFA n-3 type fatty acids.
Open Access
Effect of different cryodiluents on Nguni bull semen viability and in vitro fertilizing capacity
(University of the Free State, 2010-11) Mohapi, Maliengoane Rebecca; Lehloenya, K. C.; Greyling, J. P. C.; Nedambale, T. L.
This study was aimed at evaluating the effects of different extenders and cryoprotectants on the quality of Nguni bull semen after cryopreservation, and to evaluate the performance of frozen-thawed Nguni bull semen in IVF. The study was conducted at ARC-Animal Improvement Institute in Pretoria, in conjunction with the University of the Free State from April to October 2008. Three Nguni bulls (average age of 5 years) were used, and the semen collected from each bull, twice a week, using an electroejaculator. The semen quality parameters were evaluated prior and post freezing. The parameters evaluated included sperm motility rate and percentage live sperm, semen pH and semen concentration. The semen samples collected were divided into three equal portions following every collection and allocated to three groups - based on the semen extender used. One portion was extended with egg yolk citrate, the other extended with egg yolk Tris, while the other sample was left undiluted and served as a control. Following the addition of the extenders, the semen samples were incubated for a period of 9h. Evaluation of semen quality parameters was done at 3h intervals, within that incubation period of 9 h. The egg yolk Tris extender exhibited a reduction in performance in terms of the sperm motility rate and the percentage live sperm, compared to the egg yolk citrate extender after 6 and 9h of incubation respectively. Thus the diluted semen was not further used in the second experiment. The semen samples extended with the egg yolk citrate diluents were incubated at different temperature regimes (50C and 250C) for a period of 12h, to evaluate the effect of temperature on the sperm quality of the diluted semen. In the second trial, the semen sample that was diluted with egg yolk citrate was further divided into three portions - in order to add three different cryoprotectants, namely glycerol, dimethyl sulfoxide and ethylene glycol. The percentage live sperm and the sperm motility rate of the semen sample following addition of the cryoprotectants were also evaluated after 2h of incubation but prior to freezing. The semen samples were then loaded into 0.5ml semen straws, which were sealed with polyvinyl alcohol. The semen straws were then placed in a programmable freezer for 40 minutes for semen cooling from an initial temperature of 50C, to a temperature of -1300C. After freezing the straws were removed from the programmable freezer and placed in liquid nitrogen vapour in a styro-foam box, for 5 minutes to cool the semen straws from -1300C to -1960C, after which the straws were plunged directly into liquid nitrogen (-1960C) tank, for storage until thawing. A total of 1560 bovine oocytes were retrieved by aspiration from 127 ovaries collected from Strydfontein abattoir in Pretoria. The oocytes were then matured in vitro in bovine maturation media (consisting of TCM 199, FSH, LH and estradiol), for a period of 24h. After 24h of incubation, the matured bovine oocytes with expanded layers of cumulus cells were washed in a BO-IVF solution and fertilized in vitro using frozen-thawed Nguni bull semen from the first trial, while the others were fertilized with fresh Nguni bull semen, used as a control. For IVF, mature oocytes were incubated with semen for 18h. Thereafter, the presumptive zygotes were vortexed in TCM 199 for 90 seconds in order to remove the cumulus cells. After that, the presumptive zygotes from each treatment were randomly allocated into two different culture media namely, KSOM and SOF. The control group, that is the fresh semen group (n=481), 242 zygotes were allocated to KSOM culture media, while 239 zygotes were allocated to SOF culture media containing BSA. The treatment group, that is the frozen-thawed semen (n=559), 280 zygotes were allocated to the KSOM culture media, while 279 zygotes were allocated to SOF- BSA culture media. The presumptive zygotes were then allowed to develop (incubated) for 7 days until reaching the blastocyst stage. On day 2 following IVC (onset of IVC = day 0), cleavage rate was evaluated, the presumptive zygotes at 2-4 cell stage and those at 8 cell stage were evaluated under a contrast microscope and development recorded. Thereafter, on days 2 and 5 of culture the culture media were changed. KSOM-step 1 was changed to KSOM-step 2, while SOF-BSA was changed SOF-FBS. On the 7th day the expanded blastocysts were evaluated and recorded. Extended semen exhibited a significantly (P<0.05) lower sperm concentration, than undiluted semen. The semen pH values were significantly (P<0.05) different at 0 to 3h of incubation between the treatment groups. After a period of 6h of incubation, no significant differences were recorded between the treatment groups, in terms of the semen pH. The semen pH was found to be acidic, however it became neutral after 9h of incubation in the semen sample that was diluted with egg yolk citrate extender and incubated at 50C. The percentage live sperm was similar for semen extended with egg yolk citrate and egg yolk Tris extenders incubated at 50C up to a period of 6h of incubation. Thereafter the percentage live sperm decreased in the semen sample extended with egg yolk Tris diluents, after a period of 9h of incubation (50C). The sperm motility rate was similar between the treatment groups up to 3h of incubation at 50C. After 6 and 9h of incubation (50C), there was a drastic decline in the sperm motility rate of the semen samples extended with an egg yolk Tris extender. The percentage live sperm and pH values differed significantly (P<0.05) following addition of a cryoprotectant. The semen sample in which glycerol was used (75±5.3%) exhibited a significantly (P<0.05) higher sperm survival rate, compared to the semen sample in which ethylene glycol was used (55±8.5%). Semen sample in which glycerol was used as a cryoprotectant (6.6±0.2) exhibited a significantly (P<0.05) higher pH, compared to the semen sample in which dimethyl sulfoxide was used as a cryoprotectant (6.3±0.3). The semen samples diluted at 50C exhibited a significantly (P<0.05) higher sperm concentration immediately following dilution, compared to samples diluted at 250C. The sperm motility rate immediately following dilution was similar between the treatment groups. However, the sperm motility rates at 3, 6, 9 and 12h of incubation were significantly (P<0.05) different (67±10% vs. 55±24%; 60±12% vs. 47±25%; 47±20% vs. 38±25% and 40±20% vs. 28±27%) at 50C and 250C respectively. The percentage live sperm was found to be similar between the treatment groups, up to 9h of incubation. However, after 12h incubation the semen sample incubated at 50C exhibited a significantly (P<0.05) higher percentage live sperm, compared to the sample incubated at 250C (46±21% vs 35±31%). The interaction between incubation temperature and the semen extender used did not affect all the measured sperm quality parameters. In vitro fertilization of cow oocytes with the frozen-thawed bull semen exhibited a significantly (P<0.05) higher percentage of presumptive zygotes at the 2-4 cell stage, compared to the use of fresh semen (32.1±13.0% vs. 24.3±12.8%). IVF with fresh semen (23.2±16.5%) resulted in a significantly (P<0.05) higher percentage of day 7 blastocysts, compared to the use of frozen-thawed semen (14.2±11.9%). Culturing of the presumptive zygotes with KSOM media (23.2±17.5%) exhibited a significantly (P<0.05) higher percentage of day 7 blastocysts, than culturing with SOF media (14.2±10.4%) in vitro. In conclusion, egg yolk citrate proved to be the best extender for diluting Nguni bull semen. Fresh Nguni bull semen diluted with egg yolk citrate can probably be incubated up to a period of 9h at 50C, without any detrimental effect on the percentage live sperm and the sperm motility rate. Nguni bull semen can be best frozen using glycerol as a cryoprotectant. Frozen-thawed Nguni bull semen can be successfully used in IVEP since it resulted in higher percentage of the presumptive zygotes at the 2-4 cell stage and also attained day 7 blastocysts. Frozen-thawed Nguni bull semen can also be used successfully within 60 minutes following thawing incubated at 50C. Nevertheless, fresh Nguni bull semen can still be used successfully for IVF purposes since it resulted in a higher percentage of day 7 blastocysts, compared to frozen-thawed semen. KSOM medium proved to be a better IVC medium for bovine semen than SOF medium in terms of the percentage of day 7 blastocysts obtained.
Open Access
Effect of different dietary energy levels on productive and reproductive traits in Dorper rams
(University of the Free State, 2008-02-19) Bester, Nena; Schwalbach, L. M. J.; Greyling, J. P. C.; Van der Merwe, H. J.
English: A study was conducted to evaluate the effects of different dietary energy levels on the productive (ADG, FCR, body weight, carcass) and reproductive (scrotum, testes, semen) characteristics of young Dorper rams. The study was carried out in two phases at the University of the Free State campus in Bloemfont ein, South Africa. Out of a group of 60 rams, 36 animals that were successfully trained for semen collection with the aid of an artificial vagina (AV), were selected to be part of this study and housed in individual metabolic cages. During phase 1 of this study, 36 (11 to 12 months old) Dorper rams with a mean initial body weight of 42.0 ± 0.52kg were randomly allocated to 3 groups (n=12 per group). Each group was randomly assigned to one of 3 experimental diets (treatments), formulated on a crude protein, degradable protein, calcium and phosphorus equivalent basis. A medium energy (Me) diet was formulated according to the National Research Council standards (NRC) for young growing rams to serve as the control diet. The metabolisable energy (ME) content of this diet (Me) was increased by 15 % for the high energy (He) and decreased by 15% for the low energy (Le) diets respectively. The actual ME levels for the Le, Me, He: were 6.52, 8.09 and 9.39 MJ/kg, respectively. The rams received the diets and fresh water ad libitum during a 127 day trial period and were weighed once a week. Their ADG, FCR and ME/kg weight gain calculated and compared amongst groups. During this trial, a digestibility trial was conducted for 7 days (during week 14 of the trial), using 5 randomly selected animals from each treatment group. The amount of feed offered and consumed by each animal as well as the feaces excreted daily were recorded. The chemical composition of the diets and the feaces (dry matter, energy, crude and degradable protein) were determined. Semen was collected from each ram, every forthnight for 3 consecutive days, with the aid of an AV and evaluated for volume, overall sperm motility, forward progression, sperm concentration, % live sperm and % normal sperm. The semen samples were then diluted (using a one-step dilution method with a cryodiluent containing 5% glycerol), packed in 0.25ml plastic straws, equilibrated for 4 hours and cryoperserved (frozen) in liquid nitrogen vapour (-70 ºC). One week after freezing, the semen was thawed (38 ºC for 30 seconds) and evaluated for the same qualitative parameters as the fresh semen. The results were compared amongst groups for each collection time, using ANOVA for repeated measures analysis procedures of SAS. The energy level of the diet and the collection week as well as their interaction was used as independent variables, while the different semen parameters considered were the dependent variables in the model. When means differed significantly, the Tukey method was used to compare means. At the end of this trial period, 6 rams per group were randomly selected and slaughtered at a commercial abbatoir. After slaughtering the carcass characteristics (cold carcass weight, dressing percentage, carcass grade, shoulder circumference, buttock circumference, backfat thickness, eye muscle area, marbeling and kidney fat) were recorded and compared amongst groups. The scrotum (total weight, skin weight, fat and circumference), testes (volume and weight) and epidydimis (weight and volume) characteristics were also recorded and compared between groups, using ANOVA procedures of SAS. When means differed significantly the Tukey method was used to compare means. From the independent variables considered in the model, only the diet (ME level) had a significant effect on the parameters considered. In general, an increase in dietary energy level resulted in higher growth rates, better feed conversion rates, heavier carcasses, higher dressing percentages and greater fat deposition, both in the carcass, around the kidneys and in the scrotum (particularly in the neck region, over the testicular vascular cone). It seems that the energy requirements recommended by the NRC (1985) are not applicable for early mature Dorper replacement ram lambs, as those in the He group, (real ME level similar to NRC recommendations) deposited excessive fat in their body. Despite the significant differences induced by the He on the growth performance, carcass characteristics as well as on the scrotal and testicular characteristics of Dorper rams, no detrimental effects were recorded in their semen quantity, quality and cryotolerance. During the following 90 days (phase 2), the remaining rams (n=6 per group) were further maintained on the Le diet for 90 days. This was done to simulate the situation when over-conditioned (fat) rams bought at auctions are placed on low energy diets (veld). Other objectives of this trial phase were to evaluate if the fat deposits accumulated in the scrota of rams fed on high energy diets are mobilized during subsequent periods of moderate nutritional restriction and if these nutritional restrictions induce any changes on the semen characteristics of rams. During this phase of the trial, semen was collected, with the aid of an AV, every 3 weeks during 2 consecutive days. The semen was evaluated using the same procedures described for phase 1 of this study. The rams were slaughtered at the end of this trial period (90 days) at a commercial abattoir. After slaughtering, the carcass characteristics (cold carcass weight, dressing percentage, carcass grade, shoulder circumference, buttock circumference, backfat thickness, eye muscle area, marbeling and kidney fat), the testicular (volume and weight), the scrotal (weight, circumference, skin weight and fat) and the epididymis characteristics (weight and volume) were also recorded and compared amongst groups. Data was analysed statistically using the same procedures as described for phase 1. The results of this trial clearly indicated that the scrotal fat deposits of rams previously fed on the He diet are mobilized (at least partially) during subsequent periods of moderate dietary energy restrictions without adverse effects on semen quantity and quality. This is the first time that such finding is reported. Further research on the effect of high energy diets on subsequent ram fertility (short and long terms), as well as their reversibility are warranted. Different age groups, feeding regimes and other management practices must also be associated to high energy diets in order to fully evaluate the effect of these common practices on subsequent ram fertility.
Open Access
The effect of different milk pricing schemes on a selection index for South African Holstein cattle
(University of the Free State, 2002-11) Tesfa, Kal'ab Negash; Van Wyk, J. B.; Neser, F. W. C.
English: A total of 150673 first lactation records of South African Holstein lactating cows were used to estimate the genetic parameters of milk (MY), butterfat (BFY), and protein (PRY) yields, and butterfat (BFP) and protein (PRP) percentages. The data comprising 113 056 dams and 1 429 sires, distributed over 1 205 herds, were collected over a period of 21 years, 1980 to 2000. The study was aimed at the following aspects: to determine the non - genetic factors influencing milk traits for use in the model for a subsequent genetic analysis; to estimate the variance-covariance components and heritabilities of all traits. Finally, to calculate the weighting factors for a selection index and predict the expected response to selection when using different milk pricing systems. Five fixed effects were defined, viz: milking frequency, age at calving, herd, month of calving and year of calving. Analysis of variance indicated that all effects were highly significant (p < 0.0001) explaining on average 64.60%, 62.96%, 64.36%, 15.66% and 23.86% of the total variation for MY, BFY, PRY, BFP and PRP, respectively. Considering the R2 and RMSE as an option, month of calving for all traits, milking frequency for BFP and PRP, and age at calving for PRP showed a minor contribution to the variation and were, thus, excluded from the model for the subsequent analysis. Heritability estimates varied from medium for BFY and PRY to high for MY, BFP and PRP. This indicates that faster genetic progress will be possible through selection of MY, BFP and PRP. The highly positive genetic correlation among yield traits indicates selection for milk yield will result in a favourable response with butterfat and protein yield. However, it will lead to an unfavourable response to selection for the percentage traits. This is due to a negative genetic correlation between milk yield with percentage traits. Using the Desire program, weighting factors and expected response per generation for milk, butterfat and protein yield were calculated under three milk buyers (A, B and C) pricing systems. The standard deviations of alternative breeding objectives and selection indices were also calculated. The weighting factors for milk, butterfat and protein yields were 0.16, 2.41 and 3.24 for milk buyer A, 0.04, 3.43 and 5.70 for milk buyer Band 0.03, 3.48 and 4.37 for milk buyer C, respectively. While the expected response for the corresponding traits, when the intensity of selection equals one, were +546kg, + 16.6kg and + 15.6kg for MY, BFY, PRY respectively. in the ease of milk buyer A, +509kg, +17.1kg and +15.7kg for milk buyer B and +504kg, + I7.3kg and + I5.5kg for milk buyer C. The correlations of indices of B and C with respect to index A were 0.97 and 0.84, respectively. This indicates that the loss of efficiency when selection index Band C were used is 3 % and 16 %, respectively. Rankings of Holstein cows under the three milkpricing systems were different and this indicates that depending on the choice of their breeding goals South African Holstein breeders should follow different selection programs.
Open Access
The effect of NDF content in finishing diets on performance and meat quality of lambs
(University of the Free State, 2016-02) De Klerk, Inalene; Einkamerer, O. B.; Hugo, A.; Greyling, J. P. C.
English: A study was conducted to investigate the effect of incrementally increasing NDF levels of finishing diets on apparent digestibility, production performance, FA composition, oxidative stability and tenderness of lamb. The five dietary treatments were formulated to contain a similar nutrient composition, differing only in respect to the NDF content as the primary parameter. The NDF content increased from low roughage (primarily lucerne hay as fibre source) inclusion to a high roughage inclusion rate representing a dose-response trial in the following order: 12.76% (T15), 17.69% (T30), 22.53% (T45), 27.48% (T60) and 32.40% (T75) NDF/kg DM, respectively. No rumen modifiers or buffers were added to the diet. Sixty (60) South African Mutton Merino wether lambs (29.3±1.8 kg) were randomly allocated to the five dietary treatments (n=12 lambs per treatment) and further subdivided into 12 animals per replicate (n=1 lamb per replicate). After dietary adaptation of 10 days all lambs received the experimental diets for the remaining period (51 days). Live weight and feed intake were recorded on a weekly basis. A digestibility study was conducted over a 12-day period (4-day adaptation to the faecal bags followed by an 8-day collection period) where seven lambs (mean 48.11±2.94 kg live weight; total of 35 lambs) were randomly allocated to each treatment (n=7 lambs/treatment). At the end of the production study all lambs were slaughtered. Physical carcass characteristics, muscle and subcutaneous FA composition, meat oxidation (malonaldehyde content), colour stability, as well as meat tenderness were measured. The data was subjected to analysis of variance (PROC ANOVA) of the SAS program, version 9.2 (SAS, 2008). Tukey’s honest significant difference (HSD) test was used to identify significant differences (P <0.05) between treatments. From the results of the present study it is apparent that an incremental increase in the NDF content of lamb finishing diets presented a significant decrease (P <0.05) in DM, OM, NSC, GE, CP and EE digestibilities, as well as ash solubility. In addition, the significant (P <0.05) decrease in digestible OM, NSC and EE dietary content were associated with diet digestibility and resulted in a significant decrease (P <.0001) in ME content following an increased NDF incremental inclusion. A high roughage inclusion in finishing diets for lambs (T75) resulted in a significant (P <0.05) reduction in MEI, ADG, FCR, and therefore cold carcass weight and dressing percentage. Increased dietary NDF content significantly (P <0.05) increased saturated stearic acid, and significantly (P <0.05) decreased monounsaturated oleic and vaccenic acid, polyunsaturated linoleic acid, as well as total PUFA, n-6, n-6:n-3 and PUFA:SFA ratios of both lamb meat and adipose tissue. Apart from the NDF content significantly (P <0.05) affecting the monounsaturated palmitoleic acid (decreased) and polyunsaturated CLA (C18:2c9t11;n-6) content of muscle tissue, as well as total SFA (increased) and MUFA (decreased) content of only adipose tissue, the effect of dietary treatment between lamb deposit sites seem to be similar. Neutral-detergent fibre content did significantly (P <0.05) affect meat colour stability stored for 7 days at 4oC. Neutral-detergent fibre content had no effect (P >0.05) on meat tenderness. These results suggest that the FA profile of lamb can be manipulated by altering the NDF content of the finishing diet. This however did not result, from a human health point of view, in the desirable PUFA:SFA and n-6:n-3 ratios in muscle and subcutaneous lipid tissue. It is proposed that, to increase the total UFA content and its desirable effect on the mentioned ratios of lamb meat, regression equations should be used to establish the optimum response at a given NDF inclusion. Further research attempting to manipulate specific FAs (single or total) or FA ratios of lamb meat via dietary means to meet consumers’ demands need further attention.
Open Access
The effect of season and nutrition on the reproductive potential and sexual characteristics of Boer goat bucks
(University of the Free State, 2001-12) Theron, Orion; Greyling, J. P. C.; Schwalbach, L. M. J.
English: A study to evaluate the effect of season (ambient temperature, daylight length and relative humidity) and nutrition on the reproductive potential and sexual characteristics of young Boer goat bucks was carried out between June (winter) and November (spring), 2000. This study was carried out at the University of the Free State campus in Bloemfontein, South Africa. Twelve Boer goat bucks with a mean initial age of 12 months were used in this study. These bucks were divided into two similar experimental groups, with regard to body weight. A high nutritional plane diet was randomly allocated to one group (Group H) and a low nutritional plane diet was allocated to the other group (Group L). The total mixed diet based on Themeda triandra (Red grass) summer hay, supplemented with maize meal, molasses, HPK 40, HPK 60 and lucerne at two different nutritional levels (High and Low) was given ad lib to the two respective experimental groups. Prior to the observation period, all the bucks were subjected to a prescribed diet for adaptation, for a period of 4 weeks. Then 2 weeks prior to the observation period of this trial, each group received their respective treatment diets. During these 6 weeks, the experimental bucks were trained for semen collection with the aid of an artificial vagina. Apart from the different nutritional management, both groups were housed and managed under similar conditions. Semen samples from each buck were collected by means of an artificial vagina. Semen was collected twice weekly throughout the observation period (winter and spring). In order to have a more realistic and accurate measurement an average of the two measurements taken per week (i.e. semen volume, mass motility etc.) was used as a measurement for the respective week. The following semen parameters were evaluated: semen volume, semen colour, mass motility, sperm concentration, percentage live sperm and percentage abnormal sperm. Other sexual characteristics (serum testosterone concentration, scrotal circumference, testes volume, scrotal skin thickness and libido) as well as rectal temperature and body weight was recorded every second week concurrently with semen collection. The environmental factors (ambient temperature, daylight length and relative humidity) were recorded daily. From this study it can be concluded that the semen and sexual characteristics of young Boer goat bucks observed during this trial, were markedly influenced by the week (season) in which semen was collected, although no clear seasonal trend was observed. In general the animals on the higher nutritional plane diet tended to record higher serum testosterone levels and superior semen and testicular characteristics compared to those from the group maintained on a lower plane of nutrition. These differences however were only significant at certain times of the observation period. It can be also concluded that the Boer goat buck maintains its libido and satisfactory potential fertility (testicular characteristics and semen quality) during the winter (outside the natural breeding season). The effect of season and nutrition on the fertility of Boer goat bucks would have been better evaluated, had this study been carried out for all 4 seasons of the year and the nutritional differences been more extreme.
Open Access
The effects of breed and housing system on the production and reproduction of weaner piglets in an outdoor pig unit
(University of the Free State, 1995-08) Visser, Daniël Pieter; Erasmus, G. J.; Botha, T.
Outdoor pigfarming is a concept which (within the 20th century) had its origin (revival) in the early 1950s in England. Today approximately 15% of all breeding sows in England are kept out of doors while in South Africa probably less than 0,3% of sows (recorded), are kept out of doors. The rationale for outdoor pig farming was motivated from four angles of incidence: firstly an economic viewpoint, secondly the animal's adaptability to the environment, thirdly an ethological viewpoint and finally the new political dispensation - specifically the prospective small-farmer. The ultimate aim of this study was to identify the most suitable genotype and farrowing house of outdoor pigfarming based on the reproduction information of the sow's litters. The effect of genotype was significant (P = 0.0695) only for the trait litter size at birth, implying no significant poorer performance from the other genotypes in terms of relative reproductive efficiency. The three linear models, obtained by ANOV A procedures using SAS, which were specified for the reproductive traits litter size at birth, mortality and weaning mass, could explain very little of the variation for the three traits and Rl values of 0,05, 0,086 and 0,45 were calculated for the three traits respectively. However, the effect of parity was highly significant (P = 0.0001) for all three traits. The effect of house was non-significant (P = 0.3314) for number of piglets born alive, but significant for mortality (P = 0.0548) and highly significant for weaning mass (P = 0.0056). The inferiority of farrowing house 5 was undoubtedly revealed in this study. The importance of sufficient clean and fresh straw which will not only stimulate the sow's natural nesting activities, but will also form a buffer and heating mechanism for the young piglets, was clearly shown, given the significant (P = 0.0548) effect of house on mortality rate, and the highly significant (P = 0.0056) effect of house on weaning mass. In retrospect the reproduction performance of the outdoor breeding sow is measured against the norms applicable to the modern sow, however, the outdoor sow has to reproduce while competing with all the elements of nature (Falconer's paradox). The effect of parity was highly significant (P = 0.0001) for all three traits. This study, especially Tables 4,4; 4.8 and 4.11, showed that three distinctive (significant) phases could be identified during a sow's reproductive lifetime (Figures 4.1; 4.3 and 4.4). The commencing phase (Ist and 2nd litter) where number of piglets born alive, mortality and weaning masses are at its lowest. The optimising phase (3rd to 5th litter) when numbers of piglets born alive, and weaning mass reach their optimum while mortality rate reaches the intermediate stage. The diminishing phase (from the 6th litter onwards) where the number of piglets born alive are less than the optimising phase and more than the commencing phase, and mortality rate reaches its peak and weaning mass declines significantly.