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Managing heifers to be successful primes cowherd for longevity

by Wyoming Livestock Roundup

Every operation is going to be different when it comes to heifer selection, development and management.  

University of Wyoming Beef Extension Specialist Shelby Rosasco expounds a few ideas for heifer management which can be taken back to an operation, if feasible, and explains how an operation might obtain a successful heifer.  

Considerations in development  

 There are two ways the producer can acquire heifers – retaining heifer calves from their own herds or purchasing heifers elsewhere. Either way, Rosasco shares, it comes down to managing heifers to be successful, not only in their first breeding season, but also in setting them up to be successful throughout their lifetime and encouraging tenure in the herd.  

When picking replacement heifers, the producer is looking for specific traits such as developing at a low cost, attaining puberty early and the ability to breed early, which improve the cowherd.  

“It all comes back to developing an individual heifer,” Rosasco notes. “We need to pick out the right heifer, first. I don’t think we’ll ever have an ideal cow – they always slip up somewhere unfortunately, but we’re trying to get as close as we can.” 

Retaining versus purchasing 

Whether the producer is retaining or purchasing heifers, there are pros and cons to both. 

“Retaining heifers is going to allow producers a lot of control over the genetics of the animal,” Rosasco explains. “We know who the mother is, we likely know who she was bred to and we know how she was managed and vaccinated.” 

She adds, “We know everything leading up to the first breeding season.” 

However, Rosasco notes, this can be a lot of time and money for some producers who do not find retaining heifers practical.  

“Purchasing heifers may be ideal for someone who doesn’t have the feed resources to retain heifers,” she says.  

The choice all comes back to how it is going to fit into an individual producer’s operation and how they want to make their money back.  

Economic standpoint 

“We know the hardest thing we’re asking of a heifer is to rebreed as a first-calf heifer,” Rosasco shares. “So, how do we set her up to do a good job at this?”  

To get a heifer to perform her best from a reproductive standpoint, producers should try to breed the heifer in the first 21 days of the breeding season.  

“We have seen heifers bred in the first 21 days of the breeding season stay in the cow herd longer,” she says. “This is a big benefit to producers. We’re trying to get heifers to stay in the herd so we can breakeven and then have those heifers provide us an investment.” 

When breeding in the first 21 days, the producer is going to start to see an increase in productivity throughout their herd. 

 Rosasco continues, “Heifers calving in the first 21 days in their first calving season, not only have a higher average weaning weight the first year, but also maintain this through six calves.”  

Essentially, when adding this weight up in a six-year time span, the first-calf heifer is weaning three-quarters to a whole calf more, compared to those heifers who did not breed up in the first 21 days. 

“This is money in producers’ pockets,” she says. “These heifers are weaning more weight every year and are more efficient.”  

Calving in the first 21 days allows first-calf heifers a greater time period to recover and come back into cycle for rebreeding.  

“Producers need to be thinking of what they are investing into replacements and how fast they’re getting their investment back out of them,” she adds.  

Factors affecting infertility 

  Rosasco explains there are several factors which can affect a heifer’s infertility. Body condition, age, body weight and genetics all come into play. Rosasco especially focuses on discussing how rate of gain and nutrition play a huge role in a heifer’s infertility.  

“I’m sure if one has read any heifer development material, they have heard of this target body weight approach stating heifers need to be 60 to 65 percent of mature body weight at the start of breeding season,” Rosasco shares. “This doesn’t necessarily optimize performance, which is what producers are really looking for.”  

Focusing on lighter target body weight or low input systems allows producers to mature their heifers to 50 to 55 percent of mature body weight without impairing reproductive performance and keeping breeding development costs down.  

“Management strategies can have a pretty big impact on reproduction and longevity,” explains Rosasco.  

Some of Rosasco’s research in New Mexico was based on pushing heifers to constantly gain and managing heifers until breeding season, then pushing a gain. She shares the late-gain heifers utilized their feed and still ended up being at their ideal body weight for breeding season.  

“By utilizing this strategy, producers are being more efficient with what they are feeding heifers,” she says. “We see there is no difference in pregnancy rates and in one year, we also saw a natural flushing effect.”  

The study also shows heifers who had a constant gain had a smaller ovarian reserve, whereas heifers on stair-step diets had a larger ovarian reserve.  

“The other thing we need to be thinking about is not just what nutrition is like up to their breeding season,” states Rosasco. “Producers can’t forget what nutrition is once heifers are turned out.” 

Post AI nutrition  

Additionally, Rosasco shares a study from South Dakota State University which studied   post-artificial insemination (AI) nutrition. The first group of heifers were placed on a dry lot while the other group was free range. Heifers in both groups were at 60 to 65 percent of mature body weight.  

“Heifers from both groups were AI’d and the results show a 10 percent decrease in AI conception rates in the heifers from the dry lot,” she shares. “The data shows producers still need to be very aware of what the nutrition is like post-AI.”  

From a behavioral standpoint, the dry lot heifers are turned out and are not sure how to fend for themselves, Rosasco shares. They will spend more time trying to learn how to be free range to survive, cutting into their nutrition and affecting the success of their pregnancy.  

“Producers need to make sure they are managing fertility through each stage heifers are  going through, keeping in mind they are constantly in control of their heifers’ fertility,” she states.    

The end goal for the producer is always to manage the heifer in a way which sets her up for success to become a productive cow in the herd.   

Information in this article was presented at Fremont County Farm and Ranch Days in Riverton on Feb. 11.  

Delcy Graham is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to 

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