Attempting to improve dairy cow fertility

A seven-year study to improve dairy cow fertility has begun.

The project will create a special herd of 700 Holstein-Friesian heifer calves with low and high fertility attributes, selected from contract matings in spring this year.

With more than 2800 matings needed, DairyNZ was enlisting farmers' support to meet its target.

LIC and CRV Ambreed were helping to set up the research herd, with LIC managing the contract mating programme. It started contacting more than 1000 selected dairy farmers during the last week of May.

DairyNZ senior scientist and project leader Chris Burke said cow fertility was fundamental to dairy farm productivity, with the goal of getting as many cows as possible in calf in the first six weeks.

''More cows in calf means more milk in the vat before Christmas, fewer replacements required, more flexibility when making culling decisions to improve herds and better returns overall for dairy farmers,'' Dr Burke said.

The programme aimed to lift the six-week in-calf rate from the current average of 65% to 78%. This would deliver an estimated $500 million annual increase in profit.

''This is a challenging target that cannot be achieved using current knowledge and technologies alone,'' Dr Burke said.

''A biological breakthrough is required.

''The research herd will help us to unravel the underlying biology that differentiates genetically fertile cows from infertile cows.''

The fertility programme's biggest challenge was reducing the apparent 30% of conceptions in the first 35 days after insemination that did not become pregnancies, he said.

The magnitude, timing and possible reasons for pregnancy failure in commercially operated herds would be measured. This new work would be a collaborative effort from DairyNZ, AgResearch and Fonterra.

The project also wanted to increase the ability to select for improved fertility genotypes and give farmers new management tools to take advantage of the cows' improved genetics.