Crossbreeding offers a route to improving functional traits, such as fertility and udder health in dairy herds, but farmers should recognise that it is not a quick fix solution.
It does though provide a stopgap to solving many of the health and welfare issues currently being experienced in Holstein herds, reckoned Frank Buckley of Teagasc’s Moorepark research centre.
“But breed improvement must carry on in purebreds to ensure their is a significant gene pool to draw on for future crossbreeding programmes.”
Speaking at last week’s Semex Dairy Conference, Glasgow, Dr Buckley said crossing Norwegian Reds with Holsteins improved these functional traits significantly, with somatic cell counts showing noticeable improvements in crossbred cows compared to purebred Holsteins.
“In a study of more than 1200 cattle, 400 pure Holsteins, 400 Norwegian Red x Holstein and 400 pure Norwegian Reds, in commercial herds in Ireland, average SCC for the Holsteins was 190,000, but in the crossbreds this was much lower at 137,000. Coupled with this, only 6.9% of crossbreds had SCCs of 400,000 or more, while 9.5% of Holsteins topped this level.”
This led to 15.6% of the Holsteins suffering from mastitis compared with 11.9% of crossbreds and 11.4% of pure Norwegian Reds. “On the fertility front crossbreds recorded improved pregnancy rate to first service at 61% compared with 58% for Holsteins and 93% in-calf compared to 91% in Holsteins.”
Norwegian researcher Torstein Steine of Geno Global said that while changing the breeding goals of purebreeds was the ultimate solution it was very much a long-term issue and could take between 40 and 50 years to achieve any meaningful results. “Crossbreeding meanwhile offers a much faster route, with results seen in one or two generations. But this relies on the availablility of suitable base breeds with the required traits.”
The best option to ensure farmers had a chance to improve herd performance was to follow both routes, suggested Prof Steine. “With crossbreeding it is essential to have breeding plan and the best option is rotational crossing as this allows all females to be dams of the next generation. The only question is how many breeds should be used?” he said.
“Two breeds offers the best route as it is the simplest option. It allows easier prediction of the characteristics of future generations and concurs less risk of introducing negative effects on single traits. Also you are never many steps away from either of the starting breeds, so you can easily get back to the start should you need to.”