Abstract

Deer farmers with velvetting herds are interested in: selection of stags for superior lifetime performance; selection of stags and hinds to produce improved sons; and management of the stag herd to increase returns from velvet. Knowledge of genetic and phenotypic relationships between weights of velvet harvested at different ages and between liveweights and velvet weights will allow benefits from selection and some management practices to be quantified. This paper reports estimates of these relationships from a study involving some 2,021 stags representing 92 sire progeny groups distributed over five farms. Heritability estimates for velvet weight at successive ages from 2 to 8 year old stags ranged from 0.43 to 0.85. The average estimated genetic correlation between velvet weights in successive years was 0.97 but declined to 0.75 as the number of years between harvests increased. Phenotypic correlations were consistently lower than genetic correlations. Treating log- transformed velvet weight as a repeatable trait resulted in an estimated heritability of 0.36 with a repeatability of 0.64 and s.d. of 0.11 (log scale). Average velvet production in kg (Y) can be predicted from age in years (X) from the following equation: log10(Y) = -0.37 + 0.33*X - 0.044*X2 + 0.002*X3 Within a cohort of stags of the same age, heavier stags produced more velvet, with an average genetic correlation of 0.74 and phenotypic correlation 0.44. The genetic correlation between liveweight of hinds at 2 years of age and velvet weight at various ages averaged 0.5. Comparing different cohorts of stags of the same age, there was no relationship between average liveweights and average velvet weights. As stags aged, the average weights of velvet and liveweight increased. Describing velvet weight in kg (Y) as a non-linear function of weight in kg (X) the allometric equation was Y = 0.21*X1.4, indicating velvet weight is later maturing than liveweight.

DJ, Garrick, and GHJ Van Den Berg

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 334-337, 1996