Breeding is well and truly underway, with many farms half way through their artificial insemination (AI) programmes already.

There is not too many straws left to be ordered, but is tuberculosis (TB) resistance and other health traits something that was worth focusing on this year?

Most farmers receive their catalogues and focus on milk production, milk solids production and fertility, which are obviously crucial for the genetic gain of your herd.

However, more and more farmers are looking to improve health traits in recent years, as the health of your herd is paramount, not only for the welfare of your animals, but also for the sustainability of your farm.

TB incidence rates have increased from 3.72% back in 2019 to over 5.5% in quarter one (Q1) of 2026, resulting in 5,497 restricted herds in the first quarter of the year, which is actually down from the the corresponding figure of 6,243 for Q1 2025.

Either way TB cases have been rampant around the country, with most farmers knowing at least a neighbour or a friend who has gone down with the disease.

Which fronts the question, is it worth paying more attention to the trait when choosing the bull team?

TB resistance

During herd breakdowns, there is often only a number of cows that are actually TB reactors despite the same management conditions.

One of the reasons for this is genetic resistance to TB, where one animal has more ability to fight off infection due to its genetic makeup than another.

Therefore we have seen breeding for TB resistance make its way into catalogues over the last few years, a strategy which complements the usual controls such as testing and culling.

To improve TB resistance, farmers should be aiming to use bulls with a breeding value of less than 8% for TB, or less than 6.5% if they want a swift improvement.

The easiest way to think about it is: if you breed 100 calves off of 8% bulls, it is likely eight of those animals will go down with TB.

Farmers must understand that although a bull may have a high Economic Breeding Index (EBI), it does not guarantee favourable genetic resistance to TB, and visa versa.

Therefore, it comes back to the balancing game of which bull is ticking all the boxes, or are sacrifices to be made?

At the end of the day, you could go hard on breeding for TB resistance and still end up having reactors, as resistance is not eradication.

But genetic resistance does seem to increase your herd's chances of escaping a breakdown.