Research is underway to develop tests to identify high fertility dairy bulls and those most suitable for sexed semen production before their semen is released for sale.

Teagasc, ICBF and UCD are collaborating in a €1m research programme to create a suite of tests which will predict whether young bulls are likely to have high or low fertility levels.

The tests would also be used to choose which young bulls would be most likely to produce semen suitable for sorting into sexed semen.

Several studies have shown that the fertility of some bulls decreases significantly after semen sorting, while the semen from other bulls is able to withstand the sorting process much better, resulting in higher fertility.

Dr Stephen Butler of Teagasc Moorepark said prediction of bull fertility had become increasingly important as the AI industry became more and more focused on young bulls in recent years.

“The AI industry has changed totally in the last few years. Many of the top bulls in the active bull list now are young bulls and do not have field fertility information like daughter-proven bulls when they are first released,” he explained.

“These days, both farmers and the bull studs want young bulls to be released as soon as possible. We are proposing to develop a suite of tests that could be used to predict their likely fertility.”

“While sexed semen is primarily of interest to the dairy sector, these tests would be applicable to both dairy and beef bulls,” added Dr Butler.

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