Using genomics to breed the best females will increase the genetic value of replacements at a Welsh dairy farm and reduce the number of lower-genetic-merit animals coming into the herd.
At Marian Mawr, a Farming Connect Demonstration Farm near Rhyl, tissue samples were taken from heifers using NMR’s GeneTracker service.
The results of the Farming Connect project, revealed to farmers during an open day at the farm, showed a positive Profitable Lifetime Index (PLI) for all but one of the animals.
Genomically testing females works on the same principle as genomically testing young bulls. By taking a DNA sample from a young heifer, it is possible to get an immediate indication of genetic merit, rather than having to wait for that animal to calve and start milking. Specific animals can then be selected to produce replacements depending on individual farm breeding requirements.
At Marian Mawr, the Morris family milk a herd of 400 Holsteins with 100 heifer replacements reared annually. Milk is supplied to Muller Wiseman.
Laurence Loxam, of NMR, told farmers at the open day that even in an expanding herd, it was an economic disadvantage to breed from an animal with a negative PLI. “If you do keep her in the herd put her onto a beef animal but don’t breed your replacements from her,’’ he advised.
Genomic testing has an accuracy rate of 70% compared to between 30-35% from using parental average figures. “Genomics gives us information that we have had no chance of knowing in the past,’’ Mr Loxam explained.
Parental average figures for one of the animals tested at Marian Mawr would have scored her 109kg for milk kilograms but using genomics this figure changes to -20kg. “If the farm has a liquid milk contract then this figures shows that it wouldn’t be advisable to retain her in the herd but the flipside of this is that she has good scores for butterfat and protein so her milk would suit a manufacturing contract,’’ said Mr Loxam.
He said increasing numbers of farmers were using genomics to improve their herds. “If you have got a percentage of animals that have negative PLIs why would you keep them in the herd if they are not going to make you any money?’’
But genomics alone won’t deliver improvements if herd management is not up to scratch. “If an animal has a good PLI but the farmer doesn’t calve her down until she is 30 months old then this will have a negative impact on her performance,’’ said Mr Loxam.
AHDB Dairy Technical Officer Andy Dodd said farmers were recognising the value of PLI as a tool to shape the future direction of their herds because the benefits accumulate over the generations.
“A herd can be bred to fit a system, whether that be a grass-based farm on a constituent milk contract or one with a high-input liquid milk system,’’ said Mr Dodd, a speaker at the Marian Mawr open day.