A note on the influence of stage of lactation on the response in the lactose content of milk to a change of plane of energy nutrition in the cow

Publisher Website
Google Scholar
Abstract
Summary Three groups of Friesian cows, one of cows in early lactation, one of cows in mid-lactation and one of cows in late lactation, received over successive 4-week periods according to a double changeover Latin square design, rations providing a low, a normal and a high plane of energy nutrition. With the group of cows in early lactation the treatments were repeated again in mid-lactation and in late lactation. In all experimental groups there were increases and decreases in the treatment mean values for milk yield and solids-not-fat, protein and lactose contents, in response respectively to overfeeding and to underfeeding. The responses in lactose content in early and mid-lactation were small (overfeeding, 0·00 to +0·06 percentage units; underfeeding, −0·01 to −0·08 percentage units) and less than those in protein content, whereas in late lactation they were larger (overfeeding, +0·09 to +0·14 percentage units; underfeeding, −0·13 to −0·19 percentage units) and of the similar size to those in protein content.