Farm Table says:
What is the problem?
Reproduction rate is one of the main drivers of profitability in the northern beef industry and weaning rates of less than 50% are commonly reported for many northern Australian beef cattle herds.
Developing cost effective strategies to improve reproduction performance in the breeder herd is therefore a logical approach to help address the factors identified above.
What did the research involve?
The objective of this study was to define the genetic control of traditional and novel measures of male reproductive performance and their genetic correlations with critically important female traits, including age at puberty, post-partum anoestrous and traits associated with female lifetime reproductive performance
The Beef CRC project generated 4063 male progeny weaned from Brahman and Tropical Composite breeds over 7 years (3648 progeny evaluated to 24 months of age). The data collected allowed the estimation of breed-specific heritabilities and genetic correlations for male fertility traits and were subsequently used to estimate genetic correlations with female reproduction traits using dam/son relationships. The progeny were generated by natural mating of the cows involved in the female reproduction experiment established in Beef CRC
Bull progeny were evaluated for a range of traits at Brigalow and Belmont Research Stations from approximately 6 months of age (weaning) until 24 months of age.
What were the key findings?
This project has identified –
(i) New male traits (PNS 18 and motility) that are heritable and genetically associated with scrotal circumference or female reproductive traits;
(ii) No antagonisms with other production traits;
(iii) Potential to use male traits for indirect selection to improve both male and female reproductive performance in northern Australian herds;
(iv) Genetic parameter estimates can change with age and can impact on development of recording protocols for genetic evaluation; and
(v) Potential value in seedstock producers recording BBSE for current herd and now a role for future herd (daughters).
While motility has been identified as a useful trait in this project it was assessed by a limited number of highly skilled technical people (3 people) and the precision was good. If this trait is used widely throughout the industry as a predictor of male reproductive performance additional training and accreditation will be required by the veterinary profession.