Effects of Concentrate Supplementation Before, During, and After Milking on Milk Yield, Milk Composition, and Milk Precursors of Crossbred Dairy Cows at Haramaya University

Abstract

This study investigated the effects of concentrate feeding before milking (FBM), feeding during milking (FDM), and feeding after milking (FAM) on milk yield. composition, body condition score (BCS), and milk precursors of crossbred dairy cows at Haramaya University dairy farm. Nine crossbred dairy cows (Holstein Friesian× Horro) in the mid-lactation stage (50–75% blood level), with parity 2 & 3 and body weight range of 250-380 kg, were purposely selected and assigned to the three experimental treatments (FBM, FDM, and FAM) under a 3×3 Double Latin Square Design. The cows were fed on the same diet, and each cow was fed 0.5kg of concentrate feed per 1 kg of milk production. Each period consisted of 14 days of adaptation and 7 days of data collection. AM and PM milk yields of individual cows were recorded daily, and the average daily milk yield was calculated. Milk samples were analyzed for milk protein, fat, total solids, solids-not-fat, lactose, and ash contents at the ends of each period. Ten ml blood samples were collected and assayed for serum protein, glucose, calcium, magnesium, and phosphorus using the Cobas Integra 400 Plus machine at the Ethiopian Public Health Institute. The result indicated that cows supplemented during milking produced significantly higher milk yields (P < 0.0001) compared to those fed before milking or fed after milking. Furthermore, significantly higher fat and protein content than those of FDM and FBM. Whereas the cows fed after milking had significantly higher total solids and solids-not-fat content than those fed during milking. However, no significant differences (P > 0.05) were found in lactose and ash content across the feeding treatments. Additionally, the findings revealed no significant differences (P > 0.05) in serum protein, glucose, calcium, and magnesium levels among the treatment groups, with the exception of phosphorus. These findings underscore the importance of supplementing timing, which influenced milk yield and composition, which gave direction for optimizing dairy farm management practices to enhance productivity and milk quality. Further research is needed to explore the underlying physiological mechanisms and the long-term effects of supplementing timing on dairy cow health and performance.