Male traits and herd reproductive capability in tropical beef cattle. 2. Genetic parameters of bull traits

Corbet, N. J., Burns, B. M., Johnston, D. J., Wolcott, M. L., Corbet, D. H., Venus, B. K., Li, Y., McGowan, M. R. and Holroyd, R. G. (2013) Male traits and herd reproductive capability in tropical beef cattle. 2. Genetic parameters of bull traits. Animal Production Science, 53 2: 101-113. doi:10.1071/AN12163

Author Corbet, N. J.
Burns, B. M.
Johnston, D. J.
Wolcott, M. L.
Corbet, D. H.
Venus, B. K.
Li, Y.
McGowan, M. R.
Holroyd, R. G.
Title Male traits and herd reproductive capability in tropical beef cattle. 2. Genetic parameters of bull traits
Journal name Animal Production Science   Check publisher's open access policy
ISSN 1836-0939
Publication date 2013-01
Year available 2012
Sub-type Article (original research)
DOI 10.1071/AN12163
Open Access Status
Volume 53
Issue 2
Start page 101
End page 113
Total pages 13
Place of publication Collingwood, VIC, Australia
Publisher C S I R O
Collection year 2013
Language eng
Abstract A total of 4063 young bulls of two tropical genotypes (1639 Brahman and 2424 Tropical Composite) raised in northern Australia were evaluated for a comprehensive range of production and reproduction traits up to 24 months of age. Prior to weaning, peripheral blood concentrations of luteinising hormone (LH) and inhibin were measured at 4 months of age. At weaning (6 months) blood insulin-like growth factor-1 (IGF-I) and flight time were recorded. Body composition traits of fat depth and eye-muscle area were determined by ultrasonography at 15 months of age when additional measurements of liveweight, hip height and body condition score were recorded. Bull breeding soundness was evaluated at ~12, 18 and 24 months of age when measurements of scrotal circumference, sheath score, semen mass activity, progressive motility of individual sperm and percent morphologically normal sperm were recorded. Magnitude of heritability and genetic correlations changed across time for some traits. Heritability of LH, inhibin, IGF-I and of 18-month scrotal circumference, mass activity, progressive motility and percent normal sperm was 0.31, 0.74, 0.44, 0.75, 0.24, 0.15 and 0.25, respectively, for Brahmans and 0.48, 0.72, 0.36, 0.43, 0.13, 0.15 and 0.20, respectively, for Tropical Composites. Inhibin and IGF-I had moderate genetic association with percent normal sperm at 24 months in Brahmans but low to negligible associations in Tropical Composites. Body condition score in Brahmans and sperm motility (mass and individual) traits in both genotypes had moderate to strong genetic correlation with percent normal sperm and may prove useful candidates for indirect selection. There is scope to increase scrotal circumference by selection and this will be associated with favourable correlated responses of improved semen quality in both genotypes. The lack of genetic antagonism among bull traits indicates that selection for improved semen quality will not adversely affect other production traits.
Keyword Breeding and selection
Breeding soundness evaluation
Scrotal circumference
Semen characteristics
Northern Australia
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published: 13 December 2012.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Alliance for Agriculture and Food Innovation
Official 2013 Collection
School of Veterinary Science Publications
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