Intensive phenotyping in industry to expand the Brahman reference population

Summary

This project aimed to contribute genotypes and hard-to-measure phenotypes for male and female reproduction to the Brahman BREEDPLAN analysis from a seedstock herd, which is linked to the current Brahman population and key research herds.

The project recorded age at puberty (AP) and lactation anoestrous interval (LAI) in females and percent normal sperm (PNS) in males from three concurrent weaning groups.

BREEDPLAN results showed an increase in days to calving estimated breeding value (EBV) accuracy for the Kaiuroo females in which AP and LAI were recorded, and in PNS EBVs for the bulls recorded for the trait. There was also an increase for their sire and other related animals, both within the Kaiuroo herd and in the wider Brahman population.

Objectives

The project aims to collect genotypes and high quality phenotypes, for traits contributing to male and female reproductive performance in Brahman cattle, on approximately 500 animals in a Brahman stud that is genetically linked to the overall Brahman breed in Australia and esearch herds.

These records will contribute in realtime to the reference population for Brahman single step BREEDPLAN and help ensure that genomic breeding values for reproduction traits in Brahman cattle are at useful levels of accuracy, and hence that genomic testing in Brahman cattle is as reliable as practically possible.

Key findings

The project has provided a model for collection and use of data from industry for genomic reference, including estimates of potential costs.

Primarily, this project:

• is a useful case study for demonstrating the opportunities available to northern seedstock breeders to better describe male and female reproduction in their herds
• demonstrates the value of careful recording in terms of increasing the usefulness of genomic selection and so is a case study for breed and/or industry investment in genomic reference populations
• effectively illustrates what can be achieved when this understanding is applied to the development of breeding objectives and the application of a structure breeding program to improve reproductive performance.

Benefits to industry

Data contributed to the Brahman evaluation from this project presents opportunities for breeders to make more informed selection decisions to improve reproduction and to increase rates of genetic progress for those traits and, therefore, whole herd profitability.

For tropical beef breeds, reproductive performance is a major driver of profitability and the need for genotyping and intensive phenotyping to ensure the traits are well described across the range of genetics present in the breeds will be on-going. Industry-supported projects like this one are one means of achieving this.

MLA action

This project has opened up discussions with TBTS experts to develop an extension model built around the results of this project. This new information can be applied in the Kaiuroo herd to drive genetic improvement in male and female reproduction and genetic profitability in the herd.

Future research

As understanding of genetic evaluation in the genomic era has improved, it has become clear that there is an on-going need for traits that are given priority in the breeding objective to be well recorded in animals that have genotypes included in the analysis.

The challenges of conducting intensive phenotyping under commercial conditions cannot be understated, however, and there will always be a need for research projects to be carried out under more controlled conditions than is possible in commercial herds, to underpin the genetic evaluations for these breeds.