Genetic effects on first antler growth in relation to live-weight of red deer farmed in New Zealand

Deer farmed in New Zealand for venison production are a composite of Cervus elaphus subspecies. Venison production systems target supply of yearling males for slaughter at live-weights of ≥95 kg between 8 and 12 months of age when first antler development is occurring. If the antlers exceed 110 mm they must be removed before the animal can be transported for slaughter which adds handling and costs which some producers consider unnecessary. We hypothesised that there are associations between live-weight and first antler development that are heritable and it would be possible to select sires on the basis of delayed antler development relative to live-weight of their progeny. Antler and live-weight measurements were recorded on 1033 male progeny from three elite recorded red deer breeding herds, DNA pedigree tested as sired by 106 different stags. Spline models were fitted to the antler length and live-weight data over time. Day-of-the-year was read off these splines to define traits of live-weight when antler length reached 50 mm (WA50) or 80 mm (WA80), and antler length when live-weight reached 95 kg (AW95). The predicted traits were analysed using a single-trait animal model incorporating the extended pedigree of the animals involved to calculate three estimated breeding values (EBVs) WA50, WA80 and AW95. The three antler traits had high heritability estimates of 0.67-0.81 with standard errors of 0.10, and were moderately-highly correlated with weaning and yearling live-weight traits. The phenotypic standard deviation of WA80 of 8.35 kg or 8.6% of the mean predicted live-weight and a genetic standard deviation or 6.86 kg indicated good variation within the population, providing scope for genetically improving the current New Zealand breeding herd for delayed antler growth relative to live-weight. Such selection could reduce the number of rising yearling males requiring velvet antler removal prior to slaughter.