Back to R&D main

L.GEN.2217 - Southern Multibreed Immune Competence Project - Improving the resilience of Australian beef cattle

Ensuring cattle are immune competent is vital for minimising productive loss caused by disease, maintaining high standards of animal welfare, maximising the response to vaccines and reducing reliance on therapeutics such as antibiotics.

Project start date: 31 October 2022
Project end date: 02 March 2025
Publication date: 13 August 2025
Project status: Completed
Livestock species: Grain-fed Cattle, Grass-fed Cattle
Relevant regions: National
Download Report (2 MB)

Summary

Immune competence (IC) reflects the ability to cope with disease by mounting an effective immune response.
The measurement of IC in this study, from 3,000 cattle, extends the availability of the trait across Angus, Brahman, Charolais, Hereford, Simmental, Wagyu and associated Crossbreeds. Results reveal the contemporary distribution of the IC trait and the relationship to productivity traits. Genomic tools for breeding strategies have been delivered.

Ensuring cattle are immune competent is vital for minimising productive loss caused by disease, maintaining high standards of animal welfare, maximising the response to vaccines and reducing reliance on therapeutics such as antibiotics to prevent and treat disease.  Demonstration that IC levels are maintained within the Australian herd may provide an important and convenient metric to demonstrate the beef industry commitment to sustainability, and more generally help maintain consumer confidence in products of the beef industry.

Objectives

This study aimed to characterise the distribution of immune competence within the main beef cattle breeds in Australia to determine relationships between immune competence and other productivity traits and to deliver a genomic prediction equation for immune competence for these cattle breeds.

•    Refined resilience testing protocols, incorporating measures of immune competence, stress coping ability (through walk-over-weighing (WOW) and temperament, which are practical to conduct on-farm, and are targeted at specific breeds and specific environments.

•    Information on the distribution of performance for immune competence traits within and across breeds and breed specific genetic parameter estimates associated with immune competence and resilience-related traits. 

•    Formulas to calculate breed-specific immune competence index values for individual animals. Immune competence index values are weighted based on the heritability of component traits (which may vary between breeds), to encourage genetic gains for each trait to occur at the same rate.

•    Information describing associations between the resilience-related traits: immune competence, stress coping ability and temperament, within and across breeds and associations between these traits and health and welfare outcomes in commercial production systems.

•    Define specific attributes associated with an improved ability of cattle of particular breeds to cope with specific environmental challenges which could be utilised to improve the resilience of cattle of other breeds.

•    Identify specific genetic markers associated with an improved ability of cattle of particular breeds to cope with specific environmental challenges which could be targeted in genetic selection programs aimed at improving resilience in other breeds.

•    Development of GEBVs for resilience-related traits within and across breeds. Monitoring genetic improvement in resilience traits in beef cattle over time has the potential to be used by industry as a sustainability metric to demonstrate their ongoing commitment to improving animal health and welfare.

•    On-going communication of the project and its outcomes through Southern Multibreed extension activities in consultation with MLA and NSW DPI.

Key findings

Distribution of the immune competence trait values was assessed by breed and found to be overlapping, and as such all breeds assessed will have individuals that span low to high immune competence. A similar result was observed for crossbred animals. A slight negative genetic relationship was observed between immune competence and growth-related traits confirming that immune competence should be considered in breeding objectives to ensure no inadvertent deterioration of herd immune competence status when selecting for improved productivity. A genomic prediction equation has been produced that can be used to estimate IC values in the main Australian beef breeds and subsequent crossbred cattle.

Benefits to industry

The development of strategies aimed at improving the resilience of Australian beef cattle has the potential to:

•    increase the ability of Australian cattle to cope with environmental challenges posed by an ever-changing environment

•    improve animal health and welfare

•    reduce use of antibiotics in the food-chain and costs associated with treating disease

•    reduce wastage resulting from animal mortality/morbidity

•    provide an objective means of demonstrating industries commitment to achieving sustainability-based goals

•    maintain consumer confidence in the Australian beef industry and the products they produce.

MLA action

Review the inclusion of immune competence testing within reference populations on an ongoing basis.

Future research

Future research and recommendations:

•    collection of further IC phenotypes to improve accuracy of associated genomic predictions

•    incorporation of detailed ‘whole of life’ health (disease incidence and health-related mortality data) phenotypes for association with the immune competence trait when available

•    improve the genotype data using imputation to the 100K chip or HD level (700K)

•    adopt the CSIRO in-house genomic breed composition tool to confirm the breed composition of tested cattle (i.e. exploring the finding that the breed of some tested animals appeared to be misclassified as seen in the PCA plots)

•    explore alternative GBLUP models including effect of heterosis and inbreeding

•    explore alternative GRM including breed specific allele frequencies to determine if a generic ‘across breed’ genomic prediction provides sufficient accuracy or if breed specific genomic predictions are required to provide improved GEBV accuracy

•    cross-validation studies to assess accuracy of resulting GEBV (both within and across breeds)

•    develop genomic prediction equations for IC, with associated accuracy calculation, to identify elite animals for different breeds 

•    consider linking datasets to Angus and Brahman data (Immune competence and sensor behavioural data) collected during other projects (e.g. Angus Sire Benchmarking Projects and Northern Repronomics Project)

•    consider opportunity to develop a resilience index including traits such as immune competence, temperament, weight change over weaning across and within breeds and across different production environments.

More information

Project manager: Sarah Butler
Contact email: Reports@mla.com.au
Primary researcher: CSIRO ANIMAL FOOD & HEALTH SCIENCES