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Experts aim to breed for TB resistance


Dr Andrew Cromie ICBF. Photo: Dylan Vaughan

Dr Andrew Cromie ICBF. Photo: Dylan Vaughan

Dr Andrew Cromie ICBF. Photo: Dylan Vaughan

Researchers believe that farmers will be able to breed increasing resistance to common diseases such as mastitis, lameness and even TB in cattle populations of the future.

New data shows that the heritability of animal resistance to TB runs at 11pc in the national cattle herd.

Trinity researcher Ian Richardson analysed the parentage of over 10,000 animals slaughtered from herds with TB reactors.

It showed that up to 98pc of some bull's offspring succumbed to the disease. This contrasts with susceptibility levels of 20pc or lower in the vast majority of the population.

The Irish Cattle Breeding Federation (ICBF) believe that huge strides can be made in this latest frontier of cattle breeding.

"Fertility has a heritability of just 3pc and we've turned around the fertility of the national herd in the space of 10 years with the use of fertility indexes," said ICBF geneticist, Andrew Cromie.


It is estimated that the drop in fertility in the national herd here during the last 20 years cost Irish farmers €800m in lost earnings.

"But for a whole range of diseases from Johnes, IBR, TB, mastitis and lameness the heritability is much stronger than what we had to work with in fertility.

"Some groups of cattle that we've looked at showed a heritability for TB of 18pc, while IBR could be as high as 28pc, which is almost the same as milk production," he said.

Johnes and BVD have a heritability of 10pc, while lameness and mastitis are closer to 5pc, according to Irish research.

Dr Cromie hopes that information from meat processing plants will soon allow geneticists to get a handle on the heritability of other diseases such as pneumonia, scour and fluke.

The 140-cow Next Generation herd was set up in Moorepark last year to specifically look at some of these issues.

However, data from the herd is limited with the cows only entering their second lactation this spring.


"As regulations get tighter on the use of medicines and antibiotics, its going to be even more important that farmers are breeding animals that are as disease resistant as possible," added Dr Cromie.

"There's no silver bullet here but there are big gains for the whole industry to work together on this."

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