Having all of his young stock genotyped has completely changed the way Rob Cooper manages the breeding program of his 1300+ split calving Holstein herd
at Manilla, North West of Tamsworth, 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,”
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.
“We’ve got our first set of genomic results and I’m waiting on the results from another two batches sent off from more recent calving,” he said.
Rob says having the results has opened up new management approaches that weren’t previously possible. “Because it’s so new, our approach is still a work
in progress, but the possibilities are very exciting,” he said.
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.
“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.”
Michelle Axford from ADHIS 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.
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.