Masters Degrees (Animal, Wildlife and Grassland Sciences)
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Browsing Masters Degrees (Animal, Wildlife and Grassland Sciences) by Advisor "Du Toit, J. E. J."
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Item Open Access Die effek van die vervanging van vismeel met alternatiewe proteïenbronne in diëte van baber (Clarias gariepinus) litlinge(University of the Free State, 2010-10-23) Booysen, Rohan; Du Toit, J. E. J.Afrikaans: Intensiewe visproduksie benodig voere met ‘n hoë proteïeninhoud (Hecht, Uys & Britz, 1988). Voer is gewoonlik die grootste veranderlike koste-item in kommersiële produksie en daarom word die winsgewendheid van ‘n intensiewe produksie eenheid grootliks bepaal deur die beskikbaarheid en koste van voerproteïen. Vismeel is tradisioneel die grootste komponent van alle visvoere (Hecht, Uys & Britz, 1988). Die hoë koste van vismeel het gelei tot die soek tog na alternatiewe proteïenbronne, veral die wat nie geskik is vir menslike inname nie. In die studie is ondersoek ingestel na die effek van die vervanging van vismeel met alternatiewe proteïenbronne in diëte van (Clarias gariepinus) baberlitlinge. Die volgende plantproteïenbronne is in die studie gebruik nl. sojaboonoliekoekmeel, spirulina, grondboonoliekoekmeel en katoensaadoliekoekmeel. Dit is opgeweeg teen ‘n forelproduksierantsoen en ‘n visdieet met vismeel as proteïenbron. Die sisteem wat opgestel is, was ‘n geslote hersirkuleringseenheid wat uit dertig bakke bestaan. Die sisteem het ‘n totale volume van +/- 800 liter water en die vloeitempo van die water in die sisteem was +/- 5 liter per minuut. Die temperatuur van die water is gehandhaaf op 28 +/- 0.5oC. Driehonderd 10-week-oue babertjies is ewekansig verdeel tussen dertig bakke. Vyf bakke is toegedeel aan elke dieet m.a.w. ses rye met vyf bakke elk. Die totale biomassa is weekliks in elke bak geweeg en die voer is dienooreenkomstig aangepas. Die vissies is teen 2% van die totale biomassa gevoer vir die eerste vier weke en teen 3% vir die oorblywende vier weke. Die eksperiment is gestaak na ‘n agt weke voerperiode. Wat groei betref is gevind dat die vissies wat die vismeeldieet ontvang het die hoogste gemiddelde massatoename van die ses diëte gehad het alhoewel hul oorlewing nie baie goed was nie. Die mortaliteite van die vissies wat die spirulina-dieet ontvang het was egter die laagste van al die diëte. Dit was duidelik uit die studie dat vissies beter gegroei het op die vismeel dieet maar dat die wat die spirulina-dieet ontvang het weer meer bestand was teen strestoestande met gevolglik laer mortaliteite. Daar is dalk ‘n moontlikheid om verskillende proteïenbronne te kombineer om optimale groei en weerstand teen strestoestande te bekom en sodoende die gebruik van vismeel as die enigste bron van proteïen in visdiëte te verminder. Verdere navorsing is egter nodig.Item Open Access The influence of bedding material and collecting period on the feeding value of broiler and layer litter(University of the Free State, 2004) Jordaan, Jacobus Daniël; Du Toit, J. E. J.; Van der Merwe, H. J.Guidelines for poultry production enterprises to increase the efficiency of broiler production and optimize the nutritional value of poultry litter and manure for use in ruminant nutrition is urgently needed. Therefore a study was conducted to investigate the effect of wood shaving (SA), wheat straw (WS), peanut hulls (PH) and sunflower hulls (SH) as bedding materials on the performance of broilers in conventional floor systems. In a second study the effect of different types of bedding materials and collecting periods on the feeding value of respectively broiler and layer hen manure for ruminants were investigated. Six hundred, day old Ross -1-broilers were randomly divided into 30 groups of 20 each. Six groups (replications) were then randomly allocated to one of the following five treatments: 1. Wood shavings and saw dust (Byproduct Development Services, 0.5 to 5 cm) 2. Peanut hulls 3. Sunflower hulls 4. Wheat straw (ground through a 30 mm sieve) 5. Control group (cement floor) Commercial broiler diets were fed ad lib. to all experimental groups. On the basis of weight of water absorbed per weight of bedding material, WS absorbed significantly more water than PH, SA or SH. No significant (P>0.05) differences in the percentage moisture release of different bedding materials occurred. Accordingly no significant differences in ammonia production, feed intake, weight gain, efficiency of feed conversion, carcass weight and dressing percentage of broilers were detected among the various treatments. The highest production number (weighted sum of average weight, percent livability, period and feed conversion) was calculated for broilers on peanut hulls, followed by no bedding material (control), wood shavings, sunflower hulls and lastly wheat straw. It was calculated that a broiler excreted approximately 878g dry matter in a 42 day period. The highest (P<0.05) crude protein content occurred in the manure of broilers raised on no bedding material followed by the peanut hulls treatment. No significant differences (P>0.05) occurred in the crude protein content of manure from the wood shavings and wheat straw treatments. Bedding materials in broiler litter did not influence effective degradability of crude protein statistically significant. The highest (P<0.05) acid detergent fibre content was recorded for wood shavings and the lowest for the control treatment, while the rest showed no significant differences. No significant differences occurred in the neutral detergent fibre (NDF) content of broiler litter gathered on the different bedding materials. The lowest (P<0.05) NDF content was again found where no bedding material was supplied. No significant differences occurred in the fat content of broiler litter originating from the different treatments. The highest (P<0.05) ash content and in vitro digestibility was in the pure excretion and the lowest in broiler litter containing wood shavings. There were no significant differences amongst the remaining treatments. Bedding material had no significant (P>0.05) influence on the mineral content of broiler litter. In an effort to investigate the effect of composting time (collecting period) on the feeding value of layer hen manure, ninety, 20 week old White Plymouth Rock layer hens were then randomly divided into 30 groups of 3 each. The 30 groups were then randomly allocated to 5 treatments. The manure of each treatment was respectively collected daily and after 14, 28, 42 and 56 days. All the layers received a commercial layer diet ad lib. The collection of layer manure after 56 days resulted in a significant (P<0.05) reduction in crude protein content, degradability and in vitro digestibility. No clear trend or influence of composting time on the ADF and NDF content of layer manure could be detected. Composting time had no influence on the fat content of layer manure. The ash content of layer manure increased significantly (P<0.05) with a delaying collecting period. Delaying of collecting time resulted in an increase in the percentage of Na, Ca, K, Mg, P and Cu of layer manure. No significant (P>0.05) influence of composting time on the concentrations of Fe, Zn and Mn was observed. It was concluded from the performance of the broilers on the different bedding materials and the nutritive value of the broiler litter that peanut hulls should be preferred as bedding material. SH should be the second choice followed by WS. Lastly it seems that layer manure should be collected on a regular basis and that the composting time should not exceed 42 days.Item Open Access Influence of limestone particle size in layer diets on shell characteristics at peak production(University of the Free State, 2004-12) Phirinyane, Boitumelo Tobin; Van Der Merwe, H. J.; Du Toit, J. E. J.; Hayes, J. P.English: A study was conducted to investigate the influence of different particle sizes of a specific amorphous limestone source (calcium carbonate) in a layer diet on egg production and egg quality at peak production (week 24). Ninety nine layer pullets, 17 weeks old, were obtained from a commercial layer breeder. The pullets were randomly allocated to three groups. All the pullets received the same layer diet. The only differences among the treatment groups were that the pullets in each group received one of the three different particle sizes in the diet namely:- (a) Less than 1.0 millimetre (b) 1.0 and 2.0 millimetre (c) 2.0 and 3.8 millimetre The influence of the three particle sizes on the feed intake, body weight and egg production as well as egg characteristics was recorded. The average weekly feed intake, body weight and egg production of layers from week 18 up to 28 were not (P> 0.05) different among the layer diets with the different particle sizes. The particle size of limestone in the layer diets did not influence egg weight (P= 0.2159) and egg output (P=0.2388) significantly at peak production. Average egg weight tended (P= 0.2159) to be heavier when coarse particles were fed. No statistic al significant (P> 0.05) differences in egg volume, egg contents, egg surface area, shell weight per unit surface area, shell percentage and shell thickness occurred. According to these results limestone particle size in layer diets has no influence on eggshell quality. In the second study the effect of particle size distribution of a specific limestone source in layer diet on egg production and egg quality at peak production (week 24) was investigated. One hundred and sixty seven layer pullets , 17 weeks old, were obtained from a commercial layer breeder. The pullets were randomly allocated to five groups. All the pullets received the same layer diet. The only differences among the treatment groups were that the pullets in each group received one of five different ratios of fine (less than 1.0 mm) and coarse (between 2.0 and 3.8 mm) limestone particle size namely 100, 75, 50, 25 and 0 % fine or coarse. The influence of the five dietary limestone particle size distributions on the feed intake, body weight, and egg production of layers as well as egg characteristics mentioned in the first study were investigated. No significant (P> 0.05) influence of dietary limestone particle size distribution was found on feed intake, body weight and egg production of layers. Accordingly no significant differences occurred in egg volume, (P= 0.1310) and egg surface area (P= 0.1393). The highest (P< 0.001) egg contents were recorded where 100 and 75% fine limestone particles were included in the diet. Although significant differences for shell weight (P<0.0017) and shell percentage (P<0.0001) occurred, no clear influence of particle size distribution on these characteristics could be detected. In accordance wit h shell weight per unit surface area no significant differences (P> 0.05) in eggshell thickness occurred. It was concluded that different dietary limestone particle sizes and distributions have no influence on eggshell quality at peak production (week 24). The influence of dietary limestone particle size and distribution during the later stages of the laying period on bone formation and egg quality needs further investigation.Item Open Access Milk production of South African boer and indigenous feral goats under intensive and extensive feeding systems(University of the Free State, 1999-11) Mmbengwa, Victor Mbulaheni; Greyling, J. P. C.; Du Toit, J. E. J.English: The primary aim of this study was to investigate the milk production potential (quantity and quality) of Indigenous feral and Boer goat does under intensive and extensive nutritional regimes. The study was carried out at two different locations to accommodate the nutritional regimes. The extensive group was maintained at the Paradys experimental farm of the Department of Animal Science (Faculty of Agriculture), which is situated 20 km south of Bloemfontein. Whilst the intensive group was maintained on campus, at the Faculty of Agriculture, Bloemfontein. The animals used were 36 multiparous goat does, out of which 18 were Boer and 18 were Indigenous feral goats. Half (n = 9) of the Boer goats and half (n = 9) of the Indigenous goats were each randomly allocated to an extensive and intensive group. The intensively fed group received a complete diet. Each doe was given 2 kg/d and daily feed intake was recorded. In the extensive group, does were maintained on natural pastures with no feed supplementation. All does were milked twice a week. During each milking does were subjected to two milking periods. The first milking was done to empty the udder, and no records of milk production were taken. The second milking was undertaken two hours after the first milking, and the milk output from each teat was recorded and milk samples collected. The percentage milk fat, solids non-fat, lactose and protein in the samples were determined. Blood samples were taken once a week, to determine the serum progesterone concentrations, as an indicator of oestrous activity. All animals (does and kids) were weighed weekly to determine live weight changes during the post partum lactation period. Weekly teat measurements were also done. The Boer goat does produced more milk than Indigenous goats (P<0.05). The intensively fed Boer goat does produced their maximum quantity of milk (3.7 ± 1.4 I/day) during Week 4, compared to the extensive group that peaked (1.1 ± 0.7 I/day) at Week 8. Similarly, the. intensively fed Indigenous goats had their highest milk yield (1.9 ± 70 I/day) during Week 5, compared to the extensive group (1.1 ± 7.1 I/day) at Week 11. The intensively managed does had a maximum milk fat yield (8.79 ± 2.58% and 8.86 ± 3.68%) in Weeks 1 and 8 for Boer and Indigenous does, respectively. This maximum yield (not significantly different) was achieved in Weeks 1 and 5 for the same respective breeds in the extensive group. A correlation coefficient (r) of 0.073 between milk production and milk fat content was observed. Boer goats showed a trend of producing a higher milk lactose content throughout the trial. Boer goats fed intensively yielded maximum (5.6 ± 1.6%) and minimum (3.8 ± 0.7%) milk protein contents in Weeks 1 and 7, respectively, while for the extensive group these values were attained during Weeks 11 (7.2 ± 4.9%) and 6 (3.6 ± 0.5%), respectively. A correlation coefficient of 0.125 was recorded between milk protein content and the daily milk yield. The Boer goats in the extensive group produced the highest mean daily SNF content (10.7 ± 5.1%). The larger Boer goats had a significant (P<0.05) higher feed intake. The correlation coefficient between feed intake and milk production was 0.7 for the Boer goat and r = 0.4 for the Indigenous goat. The mean body weight was 45.0 ± 8.7 kg vs 32.3 ± 6.1 kg for Boer and Indigenous goats under the intensive feeding regime, and 42.3 ± 8.0 kg vs 29.3 ± 4.5 kg for those under an extensive feeding regime. Considerable variation in teat lengths was recorded. Peak serum progesterone concentration was recorded during Week 7 for the Boer goats (intensive group) and Week 12 for the Indigenous goats (intensive group). Ovarian activity (progesterone levels) remained low in the extensive groups throughout the observation period. Milk yield was significantly related to the nutritional status and the breed of the goat. The Boer goat produced more milk than the Indigenous goat. It is, thus, suggested that it can be used for milk production in the rural areas of South Africa. This may improve the nutrient intake of the rural communities.Item Open Access The phenotypic characterization of native Lesotho chickens(University of the Free State, 2004-11) Nthimo, A. M.; Neser, F. W. C.; Du Toit, J. E. J.; Odenya, W. O.English: Studies were made on growth, carcass and egg performance as well as mortality of the Lesotho native chickens compared to the South African native (Potchefstroom Koekoek, Ovambo, Lebowa-Venda and Naked Neck) and two exotic lines, namely the New Hampshire a nd Rhode Island Red from 3-days old to 70 weeks old (moulting). Chickens were raised in two batches with an interval of four weeks between the two batches: from 3-day old to ten and six in Batches 1 and 2, respectively. Chickens were reared in Bloemfontein (UFS) under confinement, fed ad libitum with broiler starter mash for the first four weeks where after grower mash was fed to the chickens up to the age of ten weeks old. From this stage until the end of the laying phase, they were all fed yellow maize and managed semi-intensively in Lesotho at the NULFOA. The study was done in two phases, namely the pre-laying and laying phases. With the exception of feed conversion ratio (FCR), which was conducted in the first 35 days of the study, all measurements of growth and egg performance traits were recorded weekly while mortality was recorded daily. Carcass yield analysis was done at 70 weeks of age. Presentation of the growth data was done in three stages, namely 3-day, 26-week and 70-week weights, which are considered crucial in a chicken’s life span. The means of the Lesotho line were significantly different (p<0.05) from other lines in all growth traits, namely 3-day weight, 26-week weight, average daily gain (ADG) and average weekly gain (AWG) except for the FCR and hen weight at 70 weeks old. With the exception of the New Hampshire and Potchefstroom Koekoek, no significant differences (p>0.05) were observed between the Lesotho hen weight and other lines. The Ovambo had the highest body weight and avera ge daily gain of all the native populations at 26-weeks old, while the Potchefstroom Koekoek had the highest 70-week weight. Feed conversion ratios ranged between 3.2±1.9 for the New Hampshire to 3.9±1.2 for Naked Necks in Batch 1, and 3.3±1.2 for New Hampshire to 4.2±0.9 for the Lesotho line in Batch 2. All differences between the lines for FCR were highly significant (p<0.01). All the lines commenced their egg production between the 25th to 26th weeks of age and there were no significant differences (p> 0.05) between the ages at first lay among all the lines. Egg production was found to differ significantly (p<0.05) among the different lines. The average number of eggs laid per week per hen and egg weight of the Lesotho hens was 1.2 and 48.5g, respectively. The New Hampshire had a significantly (p<0.05) higher dressed weight than other lines (1903.0±190.8g) while the Naked Neck had the lowest (1297.7±133.0g). Bone and head weight were not significantly different (p>0.05) among the different lines. The Lesotho line had the highest overall mortality (89%) of all the lines. The lowest mortality (27%) was found in the Potchefstroom Koekoek. A probable reason for high mortalities in the Lesotho could be ascribed to the result of inbreeding within the line. Although the Lesotho hens exhibited the lowest growth at the onset of laying (1113.8±71.6g), they eventually compensated and ended being large (2047.5±65.6g) at 70-weeks old. The Lesotho hen, like the New Hampshire and Potchefstroom Koekoek showed potential for being a good dual-purpose breed, since it was able to maintain a high body weight at the end of laying. Therefore the breed has an advantage of fetching a higher market price at the end of laying. The constraint is that of their low growth in the earlier part of their life span. This can be improved through the implementation of planned breeding programs.