Throwing spanner in works for advances in cattle genetics

I’ve never had much use for jargon. Thankfully, my life has moved on from the times when I had to listen to earnest people try to make a good impression with a presentation.

I expect jargon has moved on as well. My experiences are stuck in the days of blue-sky thinking and see corn ideas. Workshops, to me, are still places where people do useful things. Two are in our village: the blacksmith and the carpenter each have one.

Toolboxes are places where you are supposed to keep your spanners. Our toolboxes are always empty, their contents seemingly scattered to the four winds. The spanners are usually found under a coat in a tractor cab or on the floor where you last used them. You find th

em when you are looking for something else, but they are rarely there when you need them. I once wrote we always bought biodegradable spanners, because after two years they have disappeared. A member of staff read it and didn’t like it.

Not long after I bought an adjustable wrench used for pipe work. It was a beauty, about 4ft long. I said to the same man: “You’ll have a job to lose that.” After, a month, it had gone. To be fair, it was such a beauty someone, could have nicked it.

Breakout sessions at conferences are to be avoided at all costs. They always develop into a forum that ends up being dominated by someone who likes the sound of their voice. I usually escape these by pretending to take an urgent telephone call or an equally urgent visit to the gents.

I did get trapped in one and as it broke up, the chairman said: “You didn’t have much to say today Roger.” I replied: “No, neither did any of the others,” which I thought summed it up admirably.

bTB problem

My topic today could be easily introduced by clichés and jargon, but it won’t be. Many factors contribute to the bTB problem. Cattle movements and contact, wildlife and biosecurity all play a part to varying degrees, and those are subject to debate and controversy.

Dairy farmers are all subject to paying a levy to a board. The levy board used to be called Dairy Co, which I could always remember. Now it’s called Agriculture and Horticulture Development Board (AHDB) Dairy, which is less memorable. The levy is 0.06p per litre, which doesn’t sound like much, but if you produce a million litres a year, it comes to £600, which sounds a lot more.

I’m usually a critic of this levy board, mostly because I resent paying anything that is compulsory. But I also hope I am honest enough to give credit where credit is due. The levy board has a genetics advisory forum that includes geneticists, scientists and farmers seeking to formulate economic indices. I’m very much a layman to all this, but it’s the sort of practical information that will put a weighting on important management criteria like susceptibility to mastitis, temperament, lifespan and mobility.

We started down this road with the identification of bulls that would enhance yield, butterfat and protein. Now we can choose additional traits, such as calving ease and fertility and milking speed. It’s a sort of evolution. It gives you an opportunity to evolve the sort of cow that can flourish in the modern environment.

TB Advantage

The AHDB Dairy board has come up with TB Advantage, and good for it. TB Advantage gives farmers the opportunity to breed cows with a resistance to TB. By using the data from animals that react to the official bTB skin test, it is possible to establish which bloodlines are more resistant. The resistance, or otherwise, is expressed on a scale of +3 to -3. The range of the scale is, therefore, 6 per cent, which translates to a difference of 6 cases per 100 cattle between bulls at either end of the scale.

At first, the index will only be available on Holstein bulls, but I am sure it will be rolled out to other breeds. This is very good stuff and we know it will work because if a trait has a genetic component it is possible to select for that trait and this will lead to genetic improvement.

There is a direct count, for example, almost exactly comparable with regard to heritability as bTB. Dairy farmers have been able to select this trait as part of what they seek to improve genetically for some time – and it’s worked, because we have seen genetic indices in the national dairy herd improve. I have no doubt we will see an improvement and we will see a similar one for bTB.

The skin test is used as a basis for the index, as that is what the testing programme is based on. The false positives the skin test turns up are less than one in a thousand. If the index was simply based on animals with lesions, so much important data would go missing. Animals showing a better resistance to bTB are also likely to have better somatic cell counts, better fertility and a better profitable lifetime index.

All of these traits combine together to produce a healthier animal. It remains to be seen to what extent dairy farmers take up the TB Advantage option, but one thing is for sure – bulls with a negative score will almost certainly disappear from semen companies’ brochures. That on its own will be a step in the right direction.

The fight to eradicate bTB is about percentages and, although TB Advantage is not the whole answer, the nine per cent improvement it brings is to be welcomed. It might be only a small spanner in the toolbox at our dispersal, but a very useful one.