The behavioural recognition of gender in sheep and cattle by entire males : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science with Honours at Lincoln University, New Zealand

Abstract

A study was undertaken to define the behavioural recognition of castrated males and females by entire males in cattle and of females by partial castrates and males in sheep. In three experiments, six twenty-month-old Friesian bulls, steers and pregnant heifers and 6 two-tooth Coopworth rams, pregnant ewes and six cryptorchids were used. In experiment (1), in which all 18 animals of one species were mixed in a pen, incidence of amicable (mounting, teasing, licking) and aggressive (pushing, butting and displaying) behaviours between different gender classes were monitored by continuous recording over three hour observation periods during two days using two levels of feed allocation. In a second experiment, the preference of entire bulls towards either steers or pregnant heifers was tested. Entire males entered a race leading to a pen of castrates or pregnant females either side of the lane end. In experiment (3), the spatial distribution of entire males, free to roam around penned castrates/partial castrates and females was measured over time. Level of interest in the penned groups was also measured over time. Significant differences were found in total behaviors between species and the gender groups interacting. Bulls clearly distinguished between steers and pregnant heifers, showing more amicable and less aggressive behaviours towards heifers than steers. Bulls do not perceive steers as pregnant heifers. There was little difference in the behavioural interactions of cryptorchids and entire rams: similar incidences of both aggressive an amicable behaviours of cryptorchids and rams with ewes.