The daughters of high Balanced Performance Index (BPI) bulls produce more milk solids, make more money and last longer in the herd. This is a key finding from the ImProving Herds project, which undertook a detailed analysis of the contribution of genetics to farm business performance on 27 commercial Australian dairy farms.
ImProving Herds project leader Dr Jennie Pryce said the analysis drew upon several years of each farm's detailed physical and financial records.
"The results showed that, compared to their herd contemporaries, cows with a high BPI have higher margins over feed costs," Dr Pryce said.
"We identified the top and bottom 25 per cent of cows in each herd, based on BPI. On average, the cows in the top 25 per cent produced 88 kilograms more milk solids per cow per year and lasted eight months longer than their herd-mates in the bottom 25 per cent.
"The additional feed demands of the high BPI cows were easily recouped through additional milk income.
"On average the top 25 per cent on BPI, had about a $300/cow/year greater margin over feed and herd costs than the bottom 25 per cent."
Genotyping heifers The project also looked at the effectiveness of genotyping heifer calves as a predictor of their actual performance by following genomically tested heifer calves through their first lactation.
The results showed there was a strong relationship between the heifer genomic results for Australian Breeding Value -- ABVs -- and the first lactation production records.
"In fact, the relationship between the ABVs as heifer calves and production records is very similar to published mean reliabilities for equivalent traits," Dr Pryce said. "Farmers can be confident in using genotyping to identify replacement and surplus heifers at an earlier age."
Focus farmers involved in the project reported using genomic results to identify replacement heifers, heifers to be joined to sexed semen or to beef sires, heifers to sell for export or heifers to be grown out and sold other farmers.
Environmental impact Another module in the ImProving Herds project assessed the impact of genetic improvement on the industry's environmental footprint. The project found that breeding for high BPI reduced greenhouse gas emissions per unit of product. This is because high BPI breeds cows are more efficient producers and last longer in the herd.
Dr Pryce said the farmers involved in the project were from a range of dairying regions and different feeding systems.
"The project worked with commercial farmers and used real farm data with the aim of turning complex science into simple recommendations to help improve the bottom line of dairy businesses," she said
"The ImProving Herds project benefitted enormously from the involvement of the Focus farmers who willingly shared their experiences and insights with us so that we could determine the value of herd improvement on a dairy business' profit."
ImProving Herds was a Gardiner Dairy Foundation project in collaboration with Dairy Australia, DataGene, the Victorian Government, Holstein Australia and the National Herd Improvement Association of Australia (NHIA).
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