Effect of Concentrate Supplementation on Reproductive Performance of Smallholder Dairy Cattle in Rungwe District, Tanzania.
A study was conducted in Rungwe district in Tanzania, to assess the effect of concentrate supplementation on reproductive performance of smallholder dairy cattle. Cattle used were crossbreds, mainly between Friesian (Bos taurus) and indigenous Tanzania Short Horn Zebu (Bos indicus). All animals were managed under farmers conditions with zero-grazing mainly on natural pasture grasses and cultivated fodder comprising of Napier grass (Pennisetum purpureum), Desmodium spp. and Guatemala grass (Tripsacum laxum). The animals were allotted into supplemented (S) and control (C) groups. In addition to the basal diet, the S group received a supplement, which was formulated to contain 13.4 ME (MJ/kg), 138.1 g/kg CP, 2.3 g/kg Ca, 1.3 g/kg P and 19 mg/kg Cu. The S group had higher plasma P (1.65 vs. 1.52 ±
0.03 mmol/L) (P<0.05), Cu (7.85 vs. 6.28 ± 0.31 μmol/L) (P<0.001), and PUN (4.11 vs 3.32 ± 0.07mmol/L) compared with the C group. Postpartum ovarian cyclicity resumed before 90 days in greater proportion in the S than the C group although the association between the groups and days to initiation of cyclicity (before or after 90 days postpartum) was not statistically significant (P>0.05). Postpartum first visual oestrus was observed earlier in a larger proportion of the S compared with the C group and the association between the groups and days to postpartum first visual oestrus was significant (P<0.001). The S group had significantly (P<0.05) fewer days (103.2 ± 11.9) from parturition to first visual oestrus (DPO) than the C group (146.8 ± 15.3 days). It was concluded that there was a need for concentrate supplementation to improve the reproductive performance of dairy cattle in Rungwe district. Further studies using several supplement levels were recommended in order to come up with optimum supplement level for desired dairy cattle reproductive performance.
Keywords: Concentrate supplement, reproductive performance, small holder dairy cattle.