Selecting the right replacement heifers for the herd is a key part of a cowherd’s reproductive rate. Sandy Johnson, beef specialist at Kansas State University, said a producer’s ability to manage reproduction is an important part of getting good returns on a cow herd.
“Heterosis,” Johnson said, “can have a positive impact on reproduction.”
Johnson said a crossbred cow has heterosis, with the best traits from both breeds represented. This can lead to better calf survival, higher weaning weights and better pregnancy rates.
“In a crossbred cow’s lifetime, she can produce 17 percent more calves with a 25 percent higher cumulative weaning weight than a purebred cow would,” said Johnson. “The crossbred cows can have a $100 to $150 per cow per year advantage in profit.”
When looking for good replacement heifer, she suggests knowing what is available, whether it is from your own herd or another producer’s herd. When purchasing heifers, it’s important to know what their genetics are, what the mature cow size is of their mothers, if there are any calving difficulties in the herd and what kind of heifer development the producer does.
“Often times the bred 2-year-olds are the most expensive females on the market and you might be better off buying 3- or 4-year-old bred cows,” Johnson said.
If managing open replacement heifers, producers should decide which animals are the best to retain for breeding and what kind of breeding protocols will be used. Artificial insemination may require synchronization with different programs available. Johnson said it is also important to determine how long the AI window is, and then be sure to have bulls available to meet the genetic and calving ease components for the heifers.
“Heifers that are born earlier, will generally conceive earlier. Those who conceive earlier will produce more calves with greater longevity,” she said. “It’s important to make priorities and know how they will affect the heifer.”
South Dakota State University and Meat Animal Research Center research shows heifers that conceive within the first 21 days of calving will stay in the herd longer than those that calve in the second 21 days of the calving window or later. Early conception heifers stay in the herd longer because they are more mature at calving and become pregnant sooner in future years. These heifers also tend to wean calves with higher weaning weights.
“When producers shorten the breeding season on the heifers, they will calve sooner and stay in the herd longer,” Johnson said. “And if heifers calve 14 days prior to the cows in the herd, it gives them a better chance to rebreed within a 60-day breeding season. Late bred females become higher risk and tend to be those who fall out of the calving interval and are culled.”
She said to have goals for the replacement heifers raised within your herd. Select older heifers to keep. If the breeding season is over 30 days, then only retain the early bred heifers. Be diligent in culling late bred heifers. Push heifers to survive in a rougher environment to know which ones will reproduce better.
Making the right reproductive management decisions will help keep the females in the herd longer. These decisions include knowing how the presence or absence of heterosis will affect the herd; finding a good source of replacements or selecting the right ones out of your own herd; determining the length of the calving period and having good breeding season management.
Improvements can be seen in weaning weights when proper reproductive management is used. Selling late bred cows can increase weaning weights and shorten the calving season, but will require accurate record keeping. Factors involved in why cows become late calvers can include nutrition, genetics and age of the cow. Timely pregnancy checking can help in marketing cows that don’t fit in your system.
For example, if a producer has 100 cows and a 60 percent conception rate in the first 21 days of breeding, then 60 cows will be bred. If 60 percent of the remaining 40 conceive the second 21 days of the breeding season, 24 head will be bred. That leaves 16 head, of which 9 to 10 will conceive in the third 21 days of breeding season. The producer then needs to evaluate why the remaining six head are not pregnant.
“One method to pushing later calving cows up with the rest of the herd is through the use of synchronization with natural service,” Johnson said. “Synchronization can shorten the calving season and help add value to calves that are marketed and are the same size and age.”
Improving reproduction in a herd can add tremendous value, but Johnson said the most important way to add that value is to measure reproduction through pregnancy rate, calving rate, calving distribution, calf crop or weaning rate and by measuring body condition.
“By knowing your herd, you can manage reproductive problems and feed costs to produce cattle that will give you the best profits,” Johnson said.
For more information about reproductive management, visit www.KSUBeef.org/ManagementMinder.
Jennifer Carrico can be reached at 515-833-2120 or [email protected].
