TEMPORAL CHANGES IN MILK YIELD AND COMPOSITION OF EARLY-LACTATION MUTURU COWS UNDER SMALLHOLDER TROPICAL PRODUCTION SYSTEMS

Abstract

The temporal variations in milk yield and composition of early lactation Muturu cows in their first parity over 12 weeks were investigated in this study. Twenty Muturu cows were chosen from a mixed herd on a smallholder farm. Milk samples were collected early in the morning (0700 to 0800 hours) and documented every day. Lactose was measured in milk samples on a daily basis, while protein, total solids, fat, solid non-fat, and ash were evaluated in bulked samples using established procedures. The animals were given a diet of natural grasses and shrubs. They were given 16% CP concentrates for six weeks before and after calving. The results demonstrated that there was a statistically significant difference (P < 0.05) in both the quantity of milk produced and the nutritional content of the milk throughout the study. Overall, milk production by the Muturu breed cows increased weekly from an average of 3.65 kg during week one through an average of 5.51 kg of milk per animal during week nine, and continued to decrease as lactation progressed. As lactation progressed, the percentage of protein in the milk increased from an initial value of 3.75 percent during week one to a high value of 4.71 percent by week nine; whereas, the percentage of butter fat in the milk decreased from an initial value of 4.30 percent during week one to 3.70 percent by week seven, before increasing again. The overall trend in total solids and solid/non-fat content in the milk followed the same pattern. Simple linear regression was used to evaluate the relationship between milk yield and each component of the milk. There was a highly positive correlation between milk yield and total solids in the milk (r = 0.96, P < 0.01); likewise, there was a high positive correlation between milk yield and milk protein (r = 0.88, P < 0.01); however, there was a negative and non-statistically significant correlation between milk yield and butterfat values (r = -0.29, P < 0.01).