Eric Mousel: Possible tool in selecting replacement heifers | TSLN.com

Eric Mousel: Possible tool in selecting replacement heifers

Alaina Mousel, Editor

Photo by Alaina Mousel Clint Clark, Corson County (SD) livestock extension educator, Eric Mousel, South Dakota State University Extension range livestock specialist and Bart Carmichael, Meadow, SD, visit at the Faith Rancher's Forum, Tuesday, Feb. 8, in Faith, SD.

Can replacement heifers, when selected for fertility, impact the longevity they remain in the cowherd? That’s the question Eric Mousel, South Dakota State University Extension range livestock specialist, sought the answer to when he analyzed breeding and performance records on nearly 2,000 heifers in South Dakota.

Mousel recently presented his preliminary findings to ranchers at the 34th annual Faith Rancher’s Forum on Tuesday, Feb. 8, in Faith, SD.

“Fertility is not a highly heritable trait,” Mousel said. “It’s still important to maximize fertility, but it can ultimately take generations. What I wanted to see is if selecting for fertility in the individual is doable.”

Cattlemen select replacement heifers based on many variables – maturity, size, calving ability, sire groups, just to name a few. “Cattlemen are masters of selecting for phenotypical traits, but I wondered if there are physiological factors we can select for – and is there any economic impact?” Mousel said.

To determine an answer, Mousel collected breeding and performance records from producers throughout the state of South Dakota. These producers used a wide-variety of breeding systems: artificial insemination, natural conception, synchronization and non-synchronization. He then sorted these records based on when heifers conceived. Group 1 conceived in the first 21 days of the breeding season and group 2 conceived 21 days or later.

Initially, 92 percent of heifers conceived. Fifty-eight percent bred in the first cycle (Group 1), while 34 percent were non-first cycle breeders (Group 2). “Heifers that conceived within the first 21 days of the breeding season had 38.9 percent greater productivity over their lifetime,” he said. In other words, females from Group 1 raised 6.5 calves compared to just 4 calves raised by Group 2.

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From there, Mousel continued to examine subsequent breeding and calving seasons. “They start dropping off pretty quick; even more quickly if they didn’t breed first-cycle as a heifer,” he noted. He showed a chart depicting breed-back percentage rates for the two groups from the first calf to 10-plus calves.

“On average, about 32 percent of first-cycle breeders will pay for themselves, compared to 14 percent of second-cycle breeders,” Mousel concluded.

Can replacement heifers, when selected for fertility, impact the longevity they remain in the cowherd? That’s the question Eric Mousel, South Dakota State University Extension range livestock specialist, sought the answer to when he analyzed breeding and performance records on nearly 2,000 heifers in South Dakota.

Mousel recently presented his preliminary findings to ranchers at the 34th annual Faith Rancher’s Forum on Tuesday, Feb. 8, in Faith, SD.

“Fertility is not a highly heritable trait,” Mousel said. “It’s still important to maximize fertility, but it can ultimately take generations. What I wanted to see is if selecting for fertility in the individual is doable.”

Cattlemen select replacement heifers based on many variables – maturity, size, calving ability, sire groups, just to name a few. “Cattlemen are masters of selecting for phenotypical traits, but I wondered if there are physiological factors we can select for – and is there any economic impact?” Mousel said.

To determine an answer, Mousel collected breeding and performance records from producers throughout the state of South Dakota. These producers used a wide-variety of breeding systems: artificial insemination, natural conception, synchronization and non-synchronization. He then sorted these records based on when heifers conceived. Group 1 conceived in the first 21 days of the breeding season and group 2 conceived 21 days or later.

Initially, 92 percent of heifers conceived. Fifty-eight percent bred in the first cycle (Group 1), while 34 percent were non-first cycle breeders (Group 2). “Heifers that conceived within the first 21 days of the breeding season had 38.9 percent greater productivity over their lifetime,” he said. In other words, females from Group 1 raised 6.5 calves compared to just 4 calves raised by Group 2.

From there, Mousel continued to examine subsequent breeding and calving seasons. “They start dropping off pretty quick; even more quickly if they didn’t breed first-cycle as a heifer,” he noted. He showed a chart depicting breed-back percentage rates for the two groups from the first calf to 10-plus calves.

“On average, about 32 percent of first-cycle breeders will pay for themselves, compared to 14 percent of second-cycle breeders,” Mousel concluded.

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