Breeding program evolves with genotyping (Rob Cooper, Sep 2015)

Having all of his young stock genotyped has completely changed the way Rob Cooper manages his breeding program of his 1300+ split calving Holstein herd. Rob dairies in partnership with three investors at Manilla, north west of Tamworth, NSW.
“We rear about 600 heifer calves a year and will soon reach our target herd size of 1600. We will soon have a significant number of surplus replacements,” he said.
Rob says the combination of surplus replacements, sexed semen and genotyping will allow him to place more selection pressure on the herd to increase its Health Weighted Index (HWI) and use better genetics over the top group of heifers. Last year he sent his first batch of tail hair samples from heifer calves to be genotyped through the Clarifide service offered by Zoetis.
“We’ve got the first set of results and I’m waiting on the results from another two batches sent off from more recent calvings,” he said.
"The top 50% of heifers will be synchronised and inseminated with sexed semen, to maximise the number of heifer calves we get from our very best heifers.” The next 25% of heifers will enter the dairy herd but each year will be joined to a beef bull and their progeny will be sold. “This will allow us to maintain our herd size but we will only be breeding replacements from the top half of the herd.” The bottom 25% of heifers will be sold, possibly as young at 4 months of age.
Rob’s breeding objective is to improve functional type (udders, capacity, rump and feet and legs), fertility, mastitis, protein and fat.
Rob uses the Balanced Performance Index (BPI) to select sires. However when it comes to reviewing the heifers’ genomic results, he is most interested in their Health Weighted Index (HWI) because it is a better reflection of their genetic potential for fertility and mastitis resistance. He says the genomic results were summarised with a graph showing the whole herd with results for individual cows supplied in a sortable Excel spreadsheet.
“The graph was very useful; we could immediately see the distribution of the herd. The top and bottom 25% were very clear,” he said.
The Excel file ranked individual cows by each of the three new indices. Rob also re-sorted the list by fertility. “At this stage I’ve split the herd into three groups – the top 50%, bottom 25% and the remaining 25% – based on Health Weighted Index but I am keen to improve herd fertility so I was curious to see how they re-ranked on that.”
Having only seen one set of results so far, Rob says his system is still a work in progress. “We’ve not had this sort of information before so I am still discovering different ways to use it,” he said.
Rob thinks genomic results will be particularly useful to large herds. “With 1300+ cows, the sheer volume of information means it’s quite a complex process to make breeding decisions, especially for heifers. We have heaps of information about their mothers’ performance from herd recording, health and other farm records. But it is not so easy to put that all together with a large herd,” he said.
“Genotyping gives us powerful information from a very young age.”
Michelle Axford from DataGene said that genomic breeding values for heifers were equivalent to those based on seven lactations of herd recording data.
“Obviously it is a lot more useful to have that information at an early age than waiting nine years,” she said. “In North America – where genotyping services have been available for longer than here – there’s been a rapid increase in the number if females genotyped, especially young stock.”
Farmers have found a variety of ways to use the results to improve genetic gain in their herds.
“Some, like Rob are using genomic results to increase selection pressure on their herd. Others, especially breeders of elite genetics are using genomic results for embryo transfer; to identify elite heifers for flushing and inferior animals to use as recipients. It is becoming more common to have whole co-horts of heifers tested to inform mating and culling decisions,” Mrs Axford said.
If you’d like to send hair tail samples off for genotyping, contact Zoetis, Holstein Australia or Jersey Australia.
For more information contact Peter Williams at DataGene ph (03) 9032 7191 or email