More accurate sire values from NZ
NEW Zealands Animal Evaluation Unit has developed a cow fertility index to calculate sire breeding values for fertility which is more reliable than using calving interval alone.
The unit says the index is based on both mating and calving information, unlike other indices which are based on calving interval alone.
"The benefit of this approach is that it includes data from infertile cows which will not calve again," says the units Bill Montgomerie.
"Indices based on calving interval cannot include data from infertile cows, as you need the date of their next calving to calculate the interval. In addition, an estimate of fertility can be obtained much earlier, before the end of their lactation."
This approach is only possible because of the large New Zealand database containing 20m mating records and 10m fertility records. New Zealand Genetics used the approach to evaluate cattle genetics in New Zealand, says its general manager, Mark OConnor. "It confirmed that fertility is among the highest in the world.
"The dairy industry has for more than 50 years demanded cows which calve every 365 days. This is the reason for the development of fertile strains of cattle in New Zealand," he believes. *