Calf collection paves way for fertility project

Calf collection paves way for fertility project

A huge logistical exercise that involved collecting hundreds of calves from farms all over the North Island has set the scene for a ground-breaking research programme aimed at lifting fertility rates in the dairy industry.

In recent weeks, heifer calves from 619 farms across Waikato, Bay of Plenty, Taranaki, Manawatu and Hawke's Bay have been collected so that they can be reared and milked together as one herd. The "Animal Model" research herd will comprise equal numbers of Holstein Friesian calves with very high and very low fertility genetics, carefully selected from contract matings in spring last year and purchased from farmers by DairyNZ.

To ensure the calves are raised in controlled, identical conditions, calves needed to be collected within one to two weeks of birth. The calves are being reared together at a property in Te Awamutu to around 13 weeks of age before being moved to a large grazing property further north. The aim is to have at least 200 high fertility and 220 low fertility heifers calving in 2017.Each animal will be monitored and tests performed throughout growth, puberty, and first and second lactation as researchers look to understand more clearly what drives fertility.

DairyNZ senior scientist Susanne Meier says one of the key objectives of the Achieving Reproductive Targets programme is to discover any new traits that could be measured in heifers and would be good predictors of their eventual fertility.

"If we have a better understanding of the genetic drivers of fertility in our cows, then we can be more targeted in our breeding selections, and achieve faster gain," she says.

This could contribute to increasing the heritability of the fertility breeding value (BV), one of seven traits that make up the Breeding Worth, a selection index that ranks animals for their genetic ability to breed profitable replacements for a dairy herd.

"There's potentially a huge financial gain if we can improve reliability and breed more effectively for fertility.

"A good example may be if we found that the high fertility heifers displayed stronger heats. This is a trait that farmers can measure, and if it were a key driver for fertility, we could use that information to improve the fertility BV."

In addition to improving genetic selection for fertility, DairyNZ senior scientist and project leader Chris Burke says this purpose-bred herd will enable a thorough understanding of why some cows are easy to get back in-calf and why others are a real struggle.

"We have a group of world experts in fertility champing at the bit to use this herd to find answers," he says.

The project is part of a wider research programme funded across the dairy sector, known as Pillars of a Sustainable Dairy System.

This includes the Lifetime Productivity programme, led by DairyNZ senior scientist Claire Phyn, which focuses on premature death, involuntary culling and health-related productivity losses in dairy cows.

Between them, inefficiencies in fertility and lifetime productivity are estimated to cost the industry well over a billion dollars a year.

The Pillars of a Sustainable Dairy System programme is funded by DairyNZ with matched co-funding from the Ministry of Business, Innovation and Employment (MBIE) and funding and resources from AgResearch, Fonterra, LIC and CRV.

The research team led by DairyNZ involves AgResearch, AbacusBio, Victoria University Wellington, Cognosco (a division of Anexa Animal Health), University of Queensland, Massey University, Monash University, University of Auckland, VetSouth and New Zealand Animal Evaluation.

ENDS

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