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Breeding better beef from the dairy herd

Breeding better beef from the dairy herd

With most dairy herds finished breeding dairy replacements at this stage, farmers are typically breeding the remaining cows to beef AI or beef stock bulls. A considerable data bank is available from the Angus cross Friesian cattle finished at Grange since 2019. George Ramsbottom, Specialist outlines

This data bank allows us to look at the associations between cow beef sub index and the PTA for carcass weight of the Angus Sires which were used to breed the dairy cow dams of the steers purchased for the study.

The results show that the lower the dairy cow beef sub index or the lower the PTA for carcass weight in a beef AI sire, the lighter the carcass weight of the progeny tends to be.

Cows with a low dairy beef sub index tend to be smaller, lighter and have a greater maintenance sub index than cows with a higher dairy beef sub index. A summary of the typical results found for the Angus cross Friesian cattle is presented in the following table.

Table 1: Angus sire PTA for carcass weight (kg) required to produce 300 kg carcasses when crossed on dairy cows of differing carcass sub index (€).

 

The average Friesian dairy cow has a beef sub index of -€11. When aiming to achieve a carcass sub index of 300 kg with Angus cross Friesian cattle from such cows, we recommend that sires with a carcass weight of -4 kg or greater are used. To achieve carcasses that are 20 kg heavier, our analysis indicates that Angus sires with carcass weight PTAs that are 20 kg heavier should be used. In other words, to achieve a carcass weight of 320 kg, we’d recommend using Angus sires that are + 16 kg on dairy cows with a beef sub index of -€10. There are very few Angus sires available with carcass weights of + 15 kg or greater. Two AI sires of differing carcass weight are presented in Table 2.

Table 2: DBI and selected data on two Angus sires in AI.

The data presented in Table 2 for selected Angus AI sires show that both have a high DBI and a highly reliable proof. Sire 2 has a slightly higher calving sub index by virtue of his lower calving difficulty value for cows and heifers and shorter gestation length. However Sire 1 has a greater beef sub index because of his higher PTA for carcass weight and conformation. Both sires are recommended for use on maiden heifers.

However the value of the carcasses from the progeny of Sire 1 will be greater than those produced by Sire 2.

Farmers should look beyond the DBI when selecting beef AI sires for use on their cows.

Read more about Dairy Breeding & Genetics | Read more about Dairy Calf to Beef and Teagasc research on the topic.

The Teagasc Dairy Specialists issue an article on a topic of interest to dairy farmers every Monday here on Teagasc Daily. Find more on Teagasc Dairy here