BREEDING betters cows has resulted in as much as $532 extra, per cow each year for Gary, Ros and Justin Zweck, Blyth.
The Zwecks’ farm was one of 27 dairy farms across Australia to undergo detailed analysis by the ImProving Herds project to investigate the contribution of genetics to dairy businesses..
Using the Balanced Performance Index, it found the top 25pc in the herd produced 876 more litres of milk per cow each year, 57 more kilograms of fat and 42 more kilograms of protein than the bottom 25 per cent. On average, the top 25pc of the Zwecks’ cows also lasted in the herd eight months longer than the bottom 25pc.
The Zwecks milk 230 registered Holstein cows in a split-calving herd.
They have maintained good records on their herd, herd test every five weeks and began genomically testing heifer calves in 2014.
“Not farming in a typical dairy area can create a few challenges because it’s not as easy to chat to people about new technology and ideas in dairying,” Gary said.
“Having the opportunity to take part in the ImProving Herds project was a great opportunity to learn.”
Related: Genomics aid herd decisions
Gary said they had generally based genetic selection on production and cows suited for their environment.
“We’ve been genomically testing our replacement heifers since 2014, which has given us a much broader understanding of our herd and its genetic merit,” he said.
“As a result, we are looking for bulls that are strong for kilograms of protein, fertility and teat placement.”
All heifer calves are genomically tested at 10 weeks of age.
Heifers are then ranked on BPI and type with the bottom 10pc sold for export when they reach the required export weights.
The top 80pc, based on BPI and type, are joined to sexed semen and the next 10pc are joined to Wagyu or beef semen.
“In the first season or two of genomic testing we kept a few heifers by natural joining and it quickly became clear they were nowhere near the quality of the AI-bred heifers in terms of production and subsequently some have been culled,” Gary said.
“At that point we made a policy that if we bought natural bulls they had to be genomically-tested so we knew their BPI.”
He said having more female calves to select from, combined with the ability to identify the better heifers, helped improve the rate of genetic progress.
“We are seeing increased production as more of these genomically-tested heifers come into the herd, and in turn have their own calves; the performance of the next generation of heifers keeps going up year after year,” he said.
“As more of these heifers come through the herd, the more selection pressure we can put on BPI in the future.”