Optimizing temperate cow herd efficiency - a Trans-Tasman collaboration

Summary

In Australia and New Zealand there are concerns that beef cattle selection for mature weight may lead to cows being less able to handle environmental fluctuations, which are anticipated to become more severe in many regions due to climate change.

This project sought to leverage investment in phenotyping and genotyping undertaken on behalf of New Zealand beef breeders, to enable research to generate and investigate data from Australian temperate beef breeding herds and better understand the impact of genotype by environment interactions on maternal traits.

Data collected on heifers post-weaning was shown to be useful in estimating genetic merit for fertility. The program involved strong Trans-Tasman collaboration, which will be useful in future genetics R&D for temperate beef cattle.

Objectives

The project's goal was to help bull breeders and commercial cattle producers improve cow maternal efficiency at the same time as producing high value carcases, by developing resources that add complementary data to existing Australian and New Zealand genetics projects.

The combined dataset was used to:

• define the value of recording early life fertility traits in beef cattle and potentially introduce new EBVs for early life fertility traits
• describe the economics of contrasting approaches to breeding herd management and production systems across a range of production and market environments
• determine the implications for breeding trait emphasis and cow type definition, including optimising balance between maternal and carcase quality traits.

Key findings

• Data collected on heifers post-weaning was shown to be useful in estimating genetic merit for fertility and it is recommended that early fertility and female body composition traits be included in BREEDPLAN.
• The commercial phenotypes collected for this project had limitations for inclusion in an established genetic evaluation as a result of lower data quality.
• Under a reasonable range of environmental conditions, re-ranking of performance for animals of the same genetic profile was not of sufficient magnitude to have significant impact at the economic level.
• There were almost no traits in the Hereford or Angus Trans-Tasman BREEDPLAN evaluations for which a significant genotype by environment interaction was present. This means that breeders in New Zealand can make selection decisions based on BREEDPLAN estimated breeding values (EBV’s), which will predict progeny performance in their environments as well as they do for animals managed under Australian conditions.

Benefits to industry

Project outcomes will improve the application of BREEDPLAN for temperate beef production with new EBVs, such as heifer weaning rate, age at puberty or cow body condition score, along with enhanced $ Indexes in BREEDOBJECT. 

The result will be faster genetic progress towards more accurately defined breeding goals. The results will also assist breeders and producers to respond to changing climate and enhance their ability to optimise management strategies, including stocking rate and supplementation requirements.

The results of this project will help improve our understanding of factors influencing cow productivity in both countries and the Trans-Tasman genetic evaluation for these traits. To achieve this, research and development across a number of rather disparate areas has been supported by this project.

MLA action

To further enhance adoption, clear agreed and consistent messages around maternal efficiency based on scientific evidence will be developed and these messages will be packaged into formats appropriate for commercial cattle producers and bull breeders.

Future research

Future research opportunities include:

• introducing body condition score (BCS) EBV in BREEDPLAN
• introducing height EBV into BREEDPLAN
• exploring the economics of BCS modelling
• match mating outcomes to heifer puberty - this will require data collection on naturally mated heifers.