Genetics of early conception and its relationship to growth traits in red deer (Cervus elaphus)

The genetics of early conception success and live-animal growth were studied in five herds of red deer in New Zealand. Conception date (CD) was used as the criterion of success in seasonally mated hinds, with 2493 mating records available. Liveweights analysed were weaning weight, yearling weight, 15-month weight and mature weight (hinds only). CD and liveweights were analysed using restricted maximum likelihood procedures with an animal model, including all available pedigree records. Under the management conditions applied, CD had a phenotypic standard deviation of 7.9 days, a repeatability across years of 0.29 +/- 0.03 and a direct (univariate) heritability of 0.20 +/- 0.06. Regression procedures using DNA markers to adjust the data for genetic differences resulting from an animal's ancestral region of origin (mainly western vs eastern European) had little effect on the parameter estimates above. Direct heritability estimates for the four weight traits were 0.38 +/- 0.03, 0.49 +/- 0.02, 0.48 +/- 0.04 and 0.46 +/- 0.04, respectively, while the genetic correlations between CD and these traits (e. g. using 1763 paired records of CD with yearling weight) were -0.24 +/- 0.11, -0.24 +/- 0.09, -0.16 +/- 0.10 and -0.04 +/- 0.09, respectively. Selection for earlier CD would be successful and compatible with selection for higher juvenile weights.