Some effects of season of the year and herd management upon the dairy shorthorn cow I. The effects of seasonal changes in climate, feeding and management upon the milk yields of four herds

Abstract

Milk records and records of farm and herd management collected over a 2-year period have been used to study the effects of seasonal changes in climate, feeding and management in each of four Dairy Shorthorn herds.Differences in climatic conditions and management between the four farms appeared to be reflected in mean lactation yields, herd D having a slightly higher, and herd C a considerably lower average than the other two herds.In each herd, mean yields in each week were corrected for the effects of potential productivity and mean stage of lactation of the cows to give a weekly value designated the yield index. Variations in this quantity were used as a measure of the effects of seasonal changes in climate, feeding and management upon milk yields.