Synchronized breeding of beef cows, when all cows are inseminated on the same day, reduces the time needed in the breeding season. But that is just one of the benefits discussed at a workshop at the University of Missouri Forage Systems Research Center (FSRC).
David Patterson, MU beef reproduction specialist, said more benefits come at calving season and at market time. Patterson spoke at a "Beef Reproduction and Estrus Synchronization Workshop" for herd owners.
The group was welcomed by David Davis, superintendent of the farm that has become part of the MU breeding research network.
Patterson showed the results of research on cow-herd synchronization and timed artificial insemination (AI). The work started in 1998 with the first trials at the MU Thompson Farm at Spickard, Mo.
"We now have enough research, with large numbers of cows, to show that timed
AI works," Patterson said.
This spring two experimental breeding protocols will be tested on some 800 cows in three University herds and at a co-op research farm.
Timed AI involves resetting the biological clocks on the cows in a herd, so that they come into heat at the same time and all can be bred on the same day.
Breeding time is determined by watching the calendar and the clock. In the past, AI breeding required watching the cows over their 21-day estrus cycle to detect when they were showing signs that they were receptive to beingbred.
Conception rates in recent studies consistently run in the 60-percent or higher range. By rebreeding those cows missed on the first day, herd pregnancy rates of 90 percent or more are achieved.
In the breeding methods being used, more cows become pregnant early during the breeding season.
One benefit of timed breeding is that cows have three chances of being bred in a 45-day breeding season. With a 21-day cycle, cows would normally comeinto heat only twice.
A national survey of beef producers showed that time and labor of heatdetection was the primary reason why artificial insemination is not widely practiced in U.S. beef herds, Patterson said.
AI breeding allows the use of superior genetics to improve a beef cow herd.Breeding programs can be designed to improve the herd characteristics mostneeded, such as daily gain, weaning weights, or yearling weights.
Patterson said that the beef herd improves with each generation. "We haven't tabulated the numbers yet, but we can see a definite improvement in the Thompson Farm herd," Patterson said in answer to a question about using timed AI over several years.
By grouping a calf crop, estrus synchronization results in older and heavier calves at weaning time. That in turn affects the next breeding season. "More cows and heifers calve early," Patterson said. "Replacement heifers are older at their first breeding season."
Patterson shared tips on what university herdsmen have learned in using timed breeding.
The estrus synchronization programs require a high degree of management, he cautioned.
For example, a cow's body condition score and good nutrition, play a big part in the breeding success. That applies in all cattle breeding, Patterson said, but it is especially noticeable with timed AI. "Corners should not be cut in any of the steps."
In developing new methods, there are opportunities for mistakes. "It sounds negative, but we can learn from mistakes," Patterson said. One purpose of Agricultural Experiment Station farms is to provide farmers a place to observe and learn from what is being done, before farmers try it in their
By a show of hands, about half of the workshop participants indicated that they had tried AI in their cowherds. A larger number held up their hands when asked if they were interested in using timed AI.
Patterson invited farmers at the meeting to come watch during the timed AI breeding days at the research farm nearest them. Studies are being conducted this spring at MU Thompson Farm, Spickard, Mo.; MU Greenley Research Center, Novelty, Mo.; and MU FSRC, Linneus. The beef herd at the MFA Research Farm at Marshall, Mo., is participating also.