Sexed semen could play bigger role in future of beef cattle improvementWritten by Gayle Smith
Torrington – As the cattle industry continues to struggle to meet increasing demand for beef, more replacement heifers will be needed to increase herd numbers. Using sexed semen in beef cattle may be one way to accomplish this goal.
“With cattle producers recovering from the drought and U.S. herd numbers at their lowest since pre-WWII, there is going to come a time when there will be a need for herd expansion,” according to Chance Marshall, Profitable and Sustainable Agricultural Systems Extension educator in Campbell County.
Marshall spoke on the practice of using sexed semen in beef cattle during the Southeast Wyoming Beef Conference in Torrington on Nov. 18.
“Quality replacements continue to be demanded at record high prices,” Marshall said. “There is definitely some value in retaining and selling some heifers in the future. It could be a good way for producers to increase profit while improving the genetic potential in their own herds.”
Marshall sees the use of sexed semen in beef cattle as a potential asset for these producers.
“During the last couple decades, there have been many breakthroughs in the use of sexed semen,” he explained. “Sperm cells were first sorted by gender in the late 80s. Since then, it has become a widely used practice in the dairy industry where heifer calves are of increased value over bulls calves.”
Marshall continued, “Sexed semen has also allowed dairyman to decrease generational intervals within their herd and make faster herd improvements. Use in the dairy industry has given producers a better understanding of the technological advancements and effectiveness of the procedure.”
Inside the process
The process of sorting sperm cells is called cytometry.
The semen collection is stained, and a fluorescent dye binds to the DNA within the chromosomes of the sperm cells. The X chromosomes contain three to four percent more DNA than the Y chromosomes.
Basically, X glows more brightly than Y, Marshall explained.
The samples go through a laser process that measures how brightly each sperm glows and sorts the sperm cells into gender.
During this process, some sperm cells become damaged, and some are lost.
Only 70 percent of the collection will survive the process, and only half of that, or 35 percent, is considered a marketable product, Marshall said.
“This results in decreased sperm numbers per unit and lower conception rates, which are an added cost for producers,” he noted.
Because of the decrease in conception rates, the procedure has been slower to be adopted by the beef industry.
“Conception rates from data compiled show a 10 to 15 percent decrease in conception rates in cows or heifers showing standing heat,” the educator said. “Timed artificial insemination (AI) protocols are not recommended when using sexed semen.”
The procedure also works better in herds that are adapted to AI, he noted.
In the future
Marshall said, logically, the next step would be to increase the amount of sperm per straw to compensate. However, multiple studies have shown only an increase of five to seven percent per unit by doubling or tripling the number of sperm cells per straw.
“The damage done during the sorting process just can’t be compensated enough by greater numbers of sperm cells in each unit,” he explained.
Despite the drawbacks, Marshall still sees potential for its use in beef cattle.
“Producers could use X-sorted semen to retain more heifers. It could be a good way for them to expand. The added value of replacement heifers could offset the decrease in pregnancy rates,” he explained.
“Producers could also use Y-sorted semen,” he continued. “They would have heavier calves at weaning that would be worth more. They could also earn a premium for a full load of steers versus a mixed load.”
However, Marshall is the first to admit more advances need to be made.
“Sexed semen is fragile, and errors are only magnified. Thawing, loading and proper handling is extremely important. It is not a product to practice with,” he commented. “Its use is still a bit of a gamble. More research is definitely needed to improve its future use.”