An investigation of factors related to the dominance order of a herd of dairy cows of similar age and breed

Abstract

The dominance value was calculated for each individual of a herd of dairy cows of similar age and breed. They were correlated with the animals' weights, heights at withers, peak yields, levels of aggression and blood compositions. A dominance order was constructed which was complex, and demonstrated many instances of individuals with low dominance values consistently beating animals placed higher in the order. There was a statistically significant negative correlation between dominance value and height at withers ( P < 0.05) and a positive correlation of dominance value with the number of actively aggressive encounters initiated ( P < 0.001). Smaller, more aggressive animals tended to be more dominant. The lack of correlation between dominance value and either milk yield or body weight, suggested that it was unlikely that dominant animals had a greater rate of production than subordinate animals. It was concluded that this, together with the system of management on the farm, which nullified any possible nutritional advantage for dominant individuals, were the main reasons for the lack of correlation between dominance value and the concentration of any of the blood constituents measured.