The influence of dam liveweight on the carcass weight of rising-yearling farmed red deer and wapiti crossbreds

The New Zealand Deer Industry created a Productivity Improvement Programme in 2012 with a set of production targets for improvement over 10 years. Many of the targets relate to breeding hinds and increasing progeny carcass weight is the key trait of interest outside of hind reproductive performance. In this work, the productive output of dams was investigated. Data were collected from red deer and wapiti crossbred progeny (n=2289) born and raised on 3 farms over 5 years (2011-2015) from red deer dams (n=1353), mated to 51 red or wapiti stags. Data was analysed using a restricted maximum likelihood (REML) mixed model approach to produce predictive models of dam production outputs across a range of liveweights. The most influential fixed effect in the model was sex, followed by dam mature weight. Predictions were produced for dam mature weight against progeny carcass weight for male red deer and female and male wapiti-crossbred at a mean slaughter age of 348 days. For the target 115kg red deer dam, the goal of a 64kg progeny carcass would not be achieved in this population. That is, a 115kg red deer dam was predicted to produce 58, 63 and 54.5kg carcasses for red male, wapiti-crossbred male and female carcasses respectively. To produce a 64kg carcass would require a red deer dam of approximately 140, 120 and 150kg mature liveweight, for red male, wapiti-crossbred male and female progeny respectively. In this trial, the slaughter date was around 06 November, whereas the industry target date is 01 February. This extra time to slaughter should in theory give progeny the opportunity increase carcass weights and increase the productive output of the dam relative to her own liveweight, but by how much could not be determined from this study.