Effects of body condition at calving on milk yield and composition, lactation curve and body reserve mobilization of Holstein cows

The effects of body condition at calving on milk yield, milk composition, lactation curve and body tissue mobilization patterns were evaluated in Holstein cows. Thirteen primiparous and 38 multiparous cows were assigned body condition scores at calving (BCC). Those with BCC equal to or greater than 3.25 were assigned to class 1; while those with BCC less than 3.25 constituted class 2. These BCC classes did not affect milk yield, milk composition (except for fat percentage) or lactation curve significantly in primiparous cows. In multiparous cows, however, class I individuals had higher total milk yield, higher peak milk yield, higher milk composition percentages and more effective mobilization of body tissue reserves than cows in class 2. Among those cows that had higher BCC, those with more effective mobilization of body tissue reserves at the beginning of lactation had higher milk yields. Cows with higher BCC were heavier at prepartum and at calving in comparison to cows with lower BCC. However, body weight at calving and change in body weight early in lactation were not related to body composition at calving and subsequent milk yield.