Social Dominance in South African Indigenous Zulu Rams

Abstract

Social ranking is usually caused by limited access to resources such as feed, water as well as mating partners. In rams, social dominance is mostly related to physical traits such as body weight, horn size, body length and scrotal circumference. The objective of the study was to determine the relationship between physical traits of Zulu sheep rams and the establishment of social rankings. The social dominance rank was determined by a feed competition test using rams of the same age. Physical traits such as body weight, chest girth, horn length, scrotal circumference and withers height were measured for each ram. Sheep A was ranked first with a 100% number of wins (P < 0.01) followed by sheep E with an 86% number of wins (P < 0.05). A positive linear relationship between time spent on the feeder against the number of wins was not significant (P > 0.05). There was a significant positive correlation between the proportions of wins against horn length (P < 0.05) and chest girth length (P < 0.05). Time spent at the feeder was positively correlated with body weight and withers height (P < 0.05). Social dominance in Zulu sheep can be determined by particular physical traits such as horn length and chest girth.