Ongoing fertility problems in dairy cows have spawned many research studies in recent years and, on many UK farms, driven increased interest in crossbreeding.
Anecdotal reports often cite dramatically increased conception rates among crossbreds compared with either of the purebreds they are derived from.
And now a wealth of research undertaken in UK situations is backing up these initial farmer perceptions.
Adding further to this battery of studies, Conrad Ferris of the Agricultural Research Institute of Northern Ireland told delegates that, while breed had no affect on the number of days before the onset of cyclicity, conception rates were significantly lower in Holsteins.
The study – undertaken on 114 Holstein, Norwegian Red, Holstein x Norwegian Red and Norwegian Red x Holstein cows – found that on average just half of Holstein cows held to first or second service.
That compared with more than three-quarters of Norwegian Reds and Holstein x Norwegian Reds holding to first service, 77% and 78%, respectively.
But top performers were the Norwegian Red x Holstein cows, which achieved a conception to first or second service rate of 87%.
“This trend was replicated in the overall pregnancy rate at the end of the breeding season.
More than 90% of Norwegian Red x Holstein cows were in calf, compared with 78% of Holstein x Norwegian Reds, 86% of Norwegian Reds and just 66% of Holsteins.”
Dr Ferris said while the number of cows involved in the study was limited, it did provide further indication of the improvements in fertility which could be achieved through crossbreeding.