Environmental Influences on Production in 100 Dairy Herds1,2

Abstract

The study of environmental variation in production among dairy herds was begun at the University of Wisconsin in 1950 in cooperation with the Animal Husbandry Research Division, United States Department of Agriculture. Results from this research formed the basis for the present study. The current research was conducted to determine if environmental effects of production among herds could be minimized, thereby making genetic appraisals more accurate. Single visits were made to 100 Holstein herds on official Dairy Herd Improvement. Ten variables were measured during the evening milking. Objective measures were made of vacuum level, pulsation rate, number of machines operated per man, per cent days in milk, herd size, and kg total digestible nutrients fed per 455kg body weight. Subjective scores were given to cow cleanliness, calf feeding, herdsmanship, and hay score. The variables with statistically significant Standard partial regression coefficients were per cent days in milk, hay score, calf feeding, and herdsmanship (.33, .28, .18, and .16, respectively). Standard partial regressions for cow cleanliness, number of machines operated per man, herd size, kg total digestible nutrients fed/455kg body weight, vacuum, and pulsation were .14, −.09, .07, .07, .03, and .01, respectively. The 10 variables accounted for 45% of the variation in milk production among herds.