dairy cows

Improving cow fertility

AbacusBio consultants Nicola Dennis and Peter Amer are working alongside DairyNZ and research partners, as part of the MBIE Pillars of a Sustainable Dairy System programme, to accelerate gains in genetic fertility in cows.

The goal for this current research programme is to enable a 5% improvement in the industry 6-week in-calf rate, with an associated farmer profit gain of up to $250 million a year.

However, achieving this target would take a long time using current knowledge and technologies alone. At today’s current genetic gain in fertility, we have to wait ten years to realise a 1% improvement in the 6-week in-calf rate through breeding. A new breakthrough is required.

“The ultimate aim of this research programme,” Nicola says, “is to deliver new traits and interventions to improve dairy cow fertility”.

One key part of the programme is the herd fertility computer model built by AbacusBio, which uses complex interactions between physiology and genetics to simulate industry records.

“The herd fertility computer model is a really effective and powerful way of being able to show industry effects, which would have taken about seven years to measure in real life,” Nicola says.

The consultants used the herd fertility computer model to simulate various options and scenarios, and predict the effects of phenotypic improvements in the underlying physiology of fertility on the 6-week in-calf rate.

The latest use for the model was to simulate some realistic scenarios around the types of breakthroughs that could come out of the research programme. These include increasing genetic gain, reducing pregnancy loss, shortening the interval from calving to first postpartum ovulation, and reducing ovulation disorders.

With modelling, we can show the interconnectedness of complex interacting effects and understand how best to select or combine effective scenarios to achieve outcomes.

“With such an ambitious industry target for reproductive performance, it’s not going to be easy. But our modelling showed that even with modest farmer uptake, the targets could be achieved within the timeframe,” Peter remarks.

The model also emphasised the economic impact of reaching the reproduction targets. “We could see tremendous cost benefits in increased survival and improved lifetime milk production,” Nicola says.

The programme will continue to use modelling to keep an eye on where the research is heading. Data coming out of the on-farm and lab research also updates the model.

“The research and the model are intricately linked,” Nicola says. “The next job lined up for the model is to simulate the lives of the high- and low-fertility experiment cows produced by the research group.”

“This will guide the management in a way that allows them to express their fertility differences, while keeping enough low-fertility cows going until the end of the experiment.”