Effect of post-partum body condition score on milk yield and composition of Friesian x Bunaji dairy cows
The study determines the effect of dam body condition on milk yield and milk composition of dairy cows. The milk production records of 60 Friesian x Bunaji dairy cows were used for the study. The body condition score (BCS) was recorded on scale 1 to 5 with an increment of 0.25 points. The mean initial milk yield (IMY), daily milk yield (DMY) and total milk yield (TMY) was 6.54, 6.51 and 1872kg, respectively, while the mean peak yield (PY), peak day (PD), peak week (PWK) and lactation length (LL) were 10.61kg, 26.94 days, 4.33 weeks and 283.87 days, respectively. The mean fat, protein and lactose content of the milk was 4.22, 4.15 and 4.00 %, respectively, while the mean fat, protein and lactose yield was 0.269, 0.272 and 0.261 kg/day. The ratios of the milk composition were FPR (1.02), FLR (1.03) and PLR (104). There was relatively high variability in the population of the experimental animals with regard to their milk yield characteristics (CV = 15.38 – 67.13%) compared to the milk composition variables (CV = 4.36 – 26.09%). The effect of dam body condition score was significant (p<0.05) on all the milk yield characteristics except IMY, PY and ADY. Dams with moderate BCS of between 2.5 to 3.5 during the lactation period takes longer days to peak yield (PD = 27.41 ± 3.27 days) and peak week (PWK = 4.43 ± 0.49 weeks) with longer lactation length (LL = 301 ± 31.17 days) and consequently higher TMY (1995.25 kg/lactation). However, those with higher BCS (>3.5) had higher IY (7.00 ± 1.86 kg) and shorter days to peak yield (PD = 20.50 ± 13.12 days), PWK (3.0 ± 1.95 weeks) and shorter LL (275.33 ± 25.44 days), which invariably resulted in relatively lower TMY (1819.83 ± 335.80 kg/lactation). The dam BCS had significant effect (p<0.05) on the percentage milk fat (MFC), milk lactose (MLC), fat protein ratio (FPR) and fat lactose ratio (FLR). Dams with higher (>3.5) BCS had higher MFC, MLC, FPR and FLR. It is obvious that BCS is an important factor that reflects the metabolic stability of dairy cows.
Keywords: Post-partum, Body condition score, Milk yield, Milk composition, Friesian X Bunaji dairy cows