Milk production of South African boer and indigenous feral goats under intensive and extensive feeding systems

Greyling, J. P. C.Du Toit, J. E. J.Mmbengwa, Victor Mbulaheni2017-05-092017-05-091999-11http://hdl.handle.net/11660/6191English: 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.Afrikaans: Die doel van hierdie studie was om die melkproduksie potensiaal (kwantiteit en kwaliteit) van Inheemse en Boerbokooie, onder intensiewe en ekstensiewe voedingstoestande, te evalueer. Die ekstensiewe studie is uitgevoer by Paradys, die proefplaas van die Departement Veekunde (Fakulteit Landbou), geleë 20 km suid van Bloemfontein. Die intensiewe diere is gehuisves op die kampus by die Fakulteit Landbou, Bloemfontein. Ses-en-dertig volwasse bokooie, waarvan 18 Boerbok en 18 Inheemse bokooie is, is in die proef gebruik. Die helfte (n = 9) van die Boerbokke en helfte (n = 9) van die Inheemse bokke is ewekansig aan die ekstensiewe en intensiewe behandelingsgroepe geallokeer. Die intensiewe groep het 'n volledige gebalanseerde dieet ontvang en die daaglikse voerinname is gemonitor. Elk van hierdie ooie is 2 kg/dag gevoer en die reste gemeet. In die ekstensiewe groep is ooie onderhou op natuurlike weiding met geen byvoeding. Alle ooie is twee maal per week gemelk. Tydens elke melk is die ooie blootgestel aan twee melksessies. Die eerste melking is gedoen om die niere te lediq en geen produksierekords is geneem. Die tweede melking is twee uur later gedoen en die melkproduksie van elke speen is geneem en melkmonsters is geneem. Die melkvet, nie-vet vaste stowwe (SNF) laktose en proteininhoud is bepaal. Bloedmonsters is een maal per week geneem vir serum progesteroon konsentrasie bepalings - as 'n aanduiding van oestrus aktiwiteit. Alle diere (ooie en lammers) is weekliks geweeg om liggaamsgewig verandering te monitor, tydens die post partum laktasie periode. Speenmates is ook weekliks gedoen. Die Boerbok het meer (P<0.05) melk geproduseer tydens die observasie periode. Die intensief gevoerde Boerbokke het hul maksimum melk geproduseer (3.7 ± 1.4 I/dag) tydens Week 4, vergeleke met die ekstensiewe groep wat gepiek het (1.1 ± 0.7 I/dag) by Week 8. Soortgelyk het die intensief gevoerde Inheemse bokke hul maksimum melk geproduseer (1.9 ± 7.0 I/dag) tydens Week 5, terwyl die ekstensiewe groep (1.1 ± 7.1 I/dag) hul hoogste produksie by Week 11 behaal het. Die intensiewe ooie het hul maksimum melkvet inhoud (8.79 ± 2.58% en 8.86 ± 3.68%) tydens Week 1 en 8 vir die Boer en Inheemse bokke respektiewelik gehad. Die ooreenstemmende melkvet inhoud (nie betekenisvol verskillend) is gekry in Week 1 en 5 vir die twee rasse respektiewelik in die ekstensiewe groepe. 'n Korrelasie van r = 0.073 is gemeet tussen melkproduksie en melkvet inhoud. Boerbokke het 'n tendens getoon om In hoë melk laktose inhoud deurgaans te handhaaf. Boerbokooie in die intensiewe groep het 'n maksimum (5.6 ± 1.6%) en minimum (3.8 ± 0.7%) melk protein inhoud in Week 1 en 7 respektiewelik gehandhaaf - terwyl in die ekstensiewe groep die respektiewelike waardes verkry is in Week 11 (7.2 ± 4.9%) en Week 6 (3.6 ± 0.5%). 'n Korrelasie van r = 0.125 is verkry tussen melk protein inhoud en melkproduksie. Die ekstensiewe Boerbokgroep het die hoogste SNF inhoud getoon (10.7 ± 5.1%) oor die totale periode. Die groter Boerbokke het 'n betekenisvolle (P<0.05) hoër voerinname gehad. Die korrelasie tussen voerinname en melkproduksie was r = 0.7 vir die Boerbok en r = 0.4 vir die Inheemse bok. Die gemiddelde liggaamsgewig vir die Boer en Inheemse bokke onder intensiewe toestande was 45.0 ± 8.7 kg en 32.3 ± 6.1 kg en 42.3 ± 8.0 kg vs 29.3 ± 4.5 kg vir die ekstensiewe groep. Heelwat variasie in speenmates is gevind. Piek serum progesteroon konsentrasie is bepaal tydens Week 7 vir die Boerbokke (intensief) en Week 12 vir die Inheemse bokke (intensief). Ovarium aktiwiteit (progesteroon waardes) het laag gebly in die ekstensiewe groepe deur die observasie periode. Melkproduksie is betekenisvol verwant met die voedingstatus en genotipe van die bok. Die kwaliteit van die melk is dieselfde as die van die melkbok. Die boerbok is bewys om meerderwaardig te wees as melkproduseerder en gegee die regte voedingsomstandighede, kan bydra om die voedingsbehoeftes van die arm plattelandse gemeenskappe te help bevredig.enGoats -- Milk yieldGoat milkFeral goats -- South AfricaDissertation (M.Sc.Agric. (Animal Science))--University of the Free State, 1999Milk production of South African boer and indigenous feral goats under intensive and extensive feeding systemsDissertationUniversity of the Free State