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Negative traits a genetic curve ball

Negative traits a genetic curve ball
Holstein-friesian breeder Denis Aitken (centre) with sons James and Andrew.

Denis Aitken’s global view of holstein friesian cattle breeding has led to some challenging observations about New Zealand’s national dairy herd, including an Achilles heel in the use of genetics.

A member of the World Holstein Friesian Federation, (WHFF) Type Harmonisation Working Group, Denis is prominent nationally and internationally in the breeding and judging scene and as an adviser.

The intricacies of holstein friesian genetics, global trends, type harmonisation and the ideal cow are all a familiar part of the Taieri dairy farmer’s world.

His decades of experience have provided him with insights into the positives and negatives of the type in New Zealand.

On the up side, cows with good conformation tend to live longer and, consequently, are able to produce more milk during their life span, which also means a lower turnover of cows in a herd, Denis says.

“A cow that lasts longer gives you a lot more profit per cow.”

The average 400-cow herd that achieves an extra lactation through longevity will net an extra $65,000 a season at $6 per kilogram of milksolids.

“Cows that are put together better last longer; their udders, feet and legs last. That’s the type of thing I travel the world lecturing on.”

In New Zealand he has seen “quite a serious issue” with rump angle in which the height of the pin bones has become too extreme over the past 20 or 30 years, resulting in calving problems, cleaning after calving, and feet and leg problems.

“It’s a huge problem in New Zealand. However, we are moving in the right direction. I’ve been campaigning now on it for about 10 years and we are changing it.”

Issues with small teat size and close rear teats have also developed. Despite advances created by the use of genetics, a potential down-side is the rapid acceleration of negative traits in cows. Before the use of genomics, bulls took three to five years to be proven and to produce a “cow on the ground”.

“Now, with genomics isolating the genes for production, for type, once a calf’s born, within a couple of months by taking blood you can see what genes that animal carries. The generation interval is getting a lot quicker, and problems can compound really quickly.”

The WHFF harmonisation working group aims to create international consistency in assessing 18 physical traits in holstein friesians by classifying or precisely defining the ideal of each of those traits and promoting an evaluation system.

Another of Denis’s roles is as a senior TOP (traits other than production) inspector in New Zealand. This involves assessing the daughters of new bulls for artificial breeding companies and training people in this role over all breeds.

He and his wife, Judy, started sharemilking on the family farm at Maungatua in 1972 and bought it in 1976.

The 260-hectare property has had registered cattle since 1951 and milks 460 to 480 cows. It is now owned by son Andrew and his wife, Sonya.

Their other son, James, and his wife, Celia, own a 95ha farm at Momona, milking 250 cows. The farms are supported by a 300ha block at Middlemarch, where the cows are wintered and young stock are reared.

Annual production per cow is impressive – 440 kilograms of milksolids at Maungatua and 470 at Momona. The difference reflects the soil types – Maungatua is predominantly clay.

Denis believes in a strong focus on profit, and both farms are system 1 or 2 with little outside inputs; strong emphasis is also placed on cow families.

“The home-farm herd is bred from only 34 cows; all 480 cows go back to just 34 foundation cows,” Denis says.

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