Advances in Use of Sexed Semen
Some producers are utilizing sexed semen to create replacement heifers from their best cows or to skew the calf crop toward a higher percentage of steers for market.
Researchers at the University of Idaho’s Nancy Cummings Research, Extension and Education Center (Salmon, Idaho) last year bred 37 cows with X-sorted semen from Bon-View New Design 878 to produce replacement heifers.
“We had a 67 percent pregnancy rate, which is very high for sexed semen,” John Hall, Extension beef specialist, says. The rest of the cows were bred to a cleanup bull introduced 14 days after AI.
“We had 25 calves from the inseminations, 24 females and 1 male — pretty typical of the ratio we see in using sex-sorted semen. In that whole group we shifted the sex ratio to 78 percent females and 22 percent males,” Hall says.
This year, working with ABS Global, they bred 100 cows with X-sorted semen, using fixed-time AI and synchronization. “We only bred the cows at one time on one day, as part of this research,” Hall says. Semen companies want to see how well this works in a typical producer situation.
Commercial producers using sexed semen to create replacement heifers can select AI sires with emphasis on efficiency, maternal traits and moderate frame size, and use cleanup bulls with emphasis on growth and carcass traits for the remainder of the calves. An alternative would be to use sexed semen from bulls with growth and carcass traits to produce a high percentage of steers, and use cleanup bulls with balanced traits to gain a few excellent replacement heifers.