Lessons From U.S. Beef Cattle Research

Press, Volume CV, Issue 31053, 7 May 1966, Page 8

Lessons From U.S. Beef Cattle Research

On the basis of research work done in the United States of America in the last 20 years there were three things that he considered were important, Dr. E. J. Warwick, chief of the beef cattle research branch of the United States Department of Agriculture, told beef cattle breeders and farmers interested in beef cattle at a meeting in Christchurch this week.

Breeders of beef eattle had to make a definite decision as to what traits or characteristics they were going to select for in their environment and under their economic conditions.

Having made this decision then they should place maximum emphasis on those traits that were important and highly heritable and seek to breed to the maximum level of performance for these traits.

In commercial herds hybrid vigour could be employed to make progress with those characteristics that were not very highly heritable. There could be dangers in cross-breeding in small herds, but their research showed that a systematic, rotational type of cross-breeding programme could be effective in raising the level of production in factors low in heritability.

But for highly heritable factors like growth-rate, Dr. Warwick said that it took a good straight breed to make a good crossbreed, and in this sense a crossbreed was only as good as the basic straight breeds. Dr. Warwick devoted a large part of his lecture, which was illustrated by slides, to a discussion of results of research in beef cattle breeding in the United States in the last 30 years and in particular in the last 20 years. He has come to New Zealand at the invitation of the Meat Board, in association with Sheep and Beef Cattle Survey of the Meat and Wool Boards. Weaning Weight For maximum production, he said, cows needed to calve each year. Cattle had to have fast growth to weaning, as all their studies showed that high weaning weights were associated with high production. But weaning weight had to be considered in relation to the live-weight of the cows as cows’ consumption of feed was approximately in relation to their live-weight, and a cow of 10001 b weaning a 5001 b calf could be more efficient than a 14001 b cow with a 7001 b calf at weaning. Some adjustment had also to be made for the progeny of younger cows as compared with older animals and this might vary with different environments and different breeds.

Cattle had to have rapid and efficient growth after weaning so that the animal reached the market in fewer days. Rapid growth was also associated with efficient growth in the sense that a lb of growth was achieved on relatively less feed. Discussing the variability in the performance of the progeny of cows and also bulls, Dr. Warwick said that a great deal of variation also occurred in carcase characteristics. This happened in cattle that a lot of people thought were “pretty good.” They were Interested in conformation for two reasons. They wanted cattle that had a conformation, which led to soundness and an active life and longevity, and a conformation that led to good carcase characteristics.

Conformation, he thought, would continue to be of importance in the future of cattle breeding, but standards had to be changed from those on which cattle had been assessed in the past. In the past in selecting for con-

formation breeders had selected cattle that fattened at a young age and cattle that put on fat smoothly, but they had not achieved anything in the way of raising the proportion of preferred or more expensive cuts. Use of ultra sonic devices for estimating thickness of fat or muscling was stall in the experimental stages. Their people were interested in relating conformation with cutting out percentage. It seemed, and they had data to support it, that what had to be looked for today was muscling in the forearm or shoulder, in the round and particularly in the depth of the twist—these were areas that were last to be covered with fat —and there was also trimness of the middle. Dr. Warwick said later that some of their people had developed considerable skill in selecting cattle that had most preferred cuts and were low in waste fat.

But, he said that there was no way yet to take a live animal and determine how palatable or tender its meat would be. Discussing breeding systems Dr. Warwick said that some traits of cattle were highly heritable and others were not. Thus whether a cow had horns or not was almost 100 per cent heritable. Birth weight was fairly highly heritable but fertility was not highly heritable. In selection for breeding he said that it was necessary to select for those things that were highly heritable. On the

other hand in a cross-breed-ing programme the greatest increases were in factors that were low in heritability because of hybrid vigour. Dr. Warwick quoted research results showing that in a cross-breeding programme with Hereford, Shorthorn and Aberdeen Angus cattle, the crossbreeds gave a 3 per cent higher calving, had an almost 5 per cent higher weaning rate and about a 1 per cent higher post-weaning gain, and at slaughter the crossbreeds had returned about £3 N.Z. more in addiiton to which there was the higher calf drop—this was in comparison with the straight breeds.

Where crossbreed cows were used Dr. Warwick said that there was a 4 to 5 per cent gain in calving and calves were about 201 b heavier at weaning. The crossbred cows dropped more calves and did a better job raising their calves.

Referring to the Charollais, Dr. Warwick said that in crosses with British breeds the crossbreed cattle grew appreciably faster to weaning than the straight breeds and somewhat faster after weaning, though the margin was not as great as before weaning, and they reached a slaughter weight of about 10001 b quite a few days earlier.

The carcases of the Charollais crosses were leaner, with less excess fat, but in relation to United States grading standards they did not grade as high and the meat was not so well marbled. On the other hand the lean meat was about as tender and palatable.

It was a type of cattle that warranted investigation under particular conditions. Dr. Warwick said that progeny testing and selective use of artificial- insemination would permit faster progress to be made in breeding that under natural service systems.

Performance testing had undergone quite considerable growth since the first organised programme had been started in the United States in Virginia in 1954. At present in 34 states extension services had initiated such programmes and usually they were now being operated by breeders’ organisations. Last year about 500,000 cows had been entered in these programmes. The principal beef cattle breeding associations had now adopted schemes of performance testing. In concluding his address, Dr. Warwick quoted a remark made a long time ago by a fellow American—it was that his listeners needed a receptive frame of mind—a happy, welcoming attitude towards change.