GRAZING BEHAVIOR OF DAIRY-CATTLE IN RELATION TO GENETIC SELECTION FORMILK-PRODUCTION

The present study was designed to examine effects of selection for mil k production on the grazing behaviour of dairy cattle. Subjects were 4 3 Holstein Friesian cows from the Langhill Dairy Herd in Edinburgh whi ch consists of two genetic lines: one selected for high milk solids yi eld and a control line of average genetic index for milk solids yield. Their behaviour was recorded in various observation periods, addition ally herbage intake on pasture was investigated. No significant influe nce was found of either milk yield or breeding value on time spent gra zing, lying, ruminating or standing or on bite rate. The influence of stage of pregnancy was stronger, however, results for heifers and cows were contrary. Heifers and cows of the selected line had higher herba ge intakes than animals of the control line.