The relationships between liveweight, growth from weaning to mating and conception rate of Bos indicus cross heifers in the dry tropics of North Queensland

Doogan, V.J.; Shepherd, R.K.; Holroyd, R.G.; Fordyce, G.; James, T.A.

The relationships between liveweight, growth from weaning to mating and conception rate of Bos indicus cross heifers in the dry tropics of North Queensland

1991

Doogan, V.J. | Shepherd, R.K. | Holroyd, R.G. (Queensland Dept. of Primary Industries, Brisbane (Australia)) | Fordyce, G. | James, T.A. (Queensland Dept. of Primary Industries, Millaroo (Australia))

In a study over 3 years of 1332 maiden heifers mated at about 2 years of age between January and March, cohort (year of branding group), liveweight at weaning, at 18 months of age, or at mating significantly affected conception rate. The liveweight responses were curvilinear, being marked up to an optimum weight and reducing thereafter: a liveweight of about 270 kg at the start of mating is indicated as a target for 80 percent conception rate in a normal year. Analyses using models incorporating liveweight and growth rate with and without the cohort effect gave indications that the cohort effect was partly related to post-weaning dry season growth rate. Heifers with low liveweight had appreciably higher conception rate if they had gained weight in the post-weaning dry season.

اظهر المزيد [+]