Evaluation of energy balance of Friesian x Bunaji dairy cows using milk composition based indicator traits

The potentials of using milk composition as indicators of energy balance (EB) in dairy cows were evaluated. Milk composition traits (milk protein, fat and lactose percentages) from thirteen (13) primiparous and 47 multiparous (F1) Friesian x Bunaji cows were studied. The milk composition was analyzed weekly from 4 to 300 days postpartum. The analyzed percentage milk fat, protein and lactose were used to calculate the other milk composition parameters. The mean estimates of EB based on milk measures for all the 3 stages of lactation were positive. However, the magnitude of the average estimates of the EB increased with stages of lactation; 21.99, 46.514 and 59.097MJ/d for stages 1, 2 and 3 respectively. The magnitude and direction of the correlations between EB and milk composition traits varied across stages of lactation; the correlation coefficient was relatively stronger in the 3rd stage than the 1st and 2nd stages of lactation. The potential indicators of EB identified from this study were the protein contained variables, such as milk protein content (MPC), fat-protein ratio (FPR), change in milk protein content (dmPc), change in fat-protein ratio (dFPR) and change in protein-lactose ratio (dPLR). These variables had strong relationship with EB both within and across lactation stages. However, dmPc seems to be the variable most common to all of these potential milk production variables. It had very strong and positive relationship with EB both within and across lactation stages. This suggested that high milk protein is associated with positive EB, while the decrease in milk protein content is associated with negative energy balance (NEB). Therefore, the dynamics of changes in milk composition measures during lactation could be used to monitor the EB status of dairy cows.Keywords: Crossbred cows, Friesian x Bunaji cows, Dairy, Lactation stages, Milk protein content, Energy balance, Indicators, Fat-protein ratio, Protein-lactose rati

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 cow