The Irish Cattle Breeding Federation (ICBF) recently launched two new tools for identifying bulls with a high resistance to TB and liver fluke.

The link between animal health and genetics has been well established – some animals are more prone to mastitis and milk fever than others.

Now, the ICBF has looked at the genetic link between TB and liver fluke and found that some bulls were significantly more susceptible to the disease than others. This is why, in the event of an outbreak, some cows get the disease while others avoid it.

A small number of bulls have a very high proportion of their progeny infected with TB and liver fluke. The worst dairy bulls have over 16% of their progeny diagnosed with TB, while the best bulls had less than 1% of their progeny diagnosed with TB in the event of an outbreak.

Avoiding using these TB-susceptible bulls will help to prevent a TB breakdown on your farm.

Similarly, a small proportion of dairy bulls have a high incidence of liver fluke in their progeny.

Some dairy bulls have over 40% of their progeny diagnosed with liver fluke, while the best bulls have less than 25% diagnosed with liver fluke.

A ranking of dairy and beef bulls’ genetic resistance to TB and liver fluke is available on the ICBF website and should be checked before choosing bulls this season.

Bulls are colour-coded green, orange and red based on their proofs.

ICBF says that the figures on TB and liver fluke prevalence will be incorporated into the active bull lists and bull search functions over time.

The next round of dairy bull evaluations is taking place early next week and the new active bull list will be published in next week’s spring AI Focus in the Irish Farmers Journal.

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