Cow and Heifer Genomics

Genomic testing allows farmers to: 

• Save money on rearing costs by not rearing heifers that are unlikely to perform.

• Make more informed decisions on which heifers to sell, when using sexed/beef semen and when purchasing females.

• Significantly fast-track genetic improvement in the herd for traits of importance such as fertility, type or A2/A2.

In herds where no surplus heifers are available, farmers may also consider selling less desirable heifers and replacing them with higher quality, genotyped heifers. If using this approach, it is important to consider the biosecurity risks associated with purchasing animals.

Genomic testing is an important tool for accurately determining animal identification and parentage and reducing pedigree errors that are known to occur in around 15% of animals. Testing is also a straightforward way to establish pedigrees in herds that do not have adequate records or do not have time to construct pedigrees.

The reliability of genomic testing of heifers at a young age is the equivalent of having data from seven lactations (Figure 1). Compared with breeding values based on pedigree alone, this is more than double the reliability. 

Figure 1. Reliabilities of genomic ABVs for heifers and 7th lactation Holstein cows (source DataGene, 2017).

Currently, genomic testing can be done for any Holstein, Jersey, or Jersey-Holstein cross animal whose sire has an Australian Breeding Value (ABV). 

The use of genomic testing of dairy heifers is rapidly increasing in Australia. The most recent data shows that over the past 12 months, commercial genotyping of females in Australia rose by more than 60% compared to the total number in 2018/19.

Dairy genomic technology was initially developed in research programs by world class Australian scientists utilising data from more than 30,000 genotyped animals, 30 years of progeny testing, herd recording, type classification and genetic evaluation programs. These research programs, including DairyBio, were funded by Dairy Australia.

Samples for genomic testing are easy to collect and can be taken at the same time as routine husbandry procedures such as ear tagging or disbudding. To obtain Tissue Sample Units (TSUs) and pliers or hair sample cards, contact your genomic service provider.

Figure 2. Collecting an ear tissue sample for genomic testing using a Tissue Sampling Unit (TSU)

The case studies below are designed to demonstrate how Australian farmers are implementing heifer genomic testing in their own businesses.