Management practices aimed at minimizing early pregnancy losses
For many producers, breeding season is underway or has recently wrapped up. Having a favorable breed-up in a producer’s herd is a top priority, but so is ensuring cows will carry the calf to term.
On a recent BeefWatch podcast, the University of Nebraska-Lincoln’s Dr. Rick Funston shared factors possibly contributing to early pregnancy loss in beef cattle and how producers can make management decisions to help prevent this.
Factors for early losses
Selection in beef cattle is one thing to consider in early pregnancy losses.
“Genetic defects cause embryonic loss,” Funston explained. “A host of genetic issues might cause embryonic loss, and producers probably don’t have much control over these issues other than not to breed to related animals.”
Though, he noted, this is where producers find genetic defects in their herds. Beyond selection, Funston shared the period leading up to breeding is extremely important.
“This period tends to be what producers have the most control over,” said Funston. “To start with, I never want animals gaining more prior to breeding than what they are going to gain post breeding.”
Most producers feel they are doing their cattle a favor by adding flesh in a feedlot setting, but realize cattle do not maintain the gain on grass.
Funston shared planning nutrition for cattle in order to always move towards improving productivity while breeding is key. This means producers might have to back cattle off feed before breeding.
“Producers will probably see gain around two pounds per day on good grass early in the breeding season, but not much more,” noted Funston.
Keeping gain right around the same amount as it would be during breeding season allows for metabolic signals to be more conducive to embryonic survival.
Transportation and loss considerations
“Transportation will also play in maintaining pregnancy as well,” said Funston.
When using artificial insemination (AI), Funston informed producers it is best to move cattle within five days or wait 40 days. During this time, clean-up bulls are critical to make up some of the loss incurred by AI.
“I always tell people sometimes our mistakes are covered up when we don’t know it,” Funston shared on the topic.
Funston worked for an operation in Wyoming where cattle were shipped across the state with clean-up bulls in with the cows one year, and the next year, clean-up bulls were not included. Unsurprisingly, the ranch saw lower pregnancy rates when the clean-up bulls were not with the cows.
“The ranch covered up their mistake when the bulls were shipped with the cows,” explained Funston. “Those cattle that have embryonic loss, the heat after that loss is at least day 45, and they are completely fertile,” shared Funston.
With transporting, Funston stressed it is important not to make large moves in the heat of the day or to try for days with cooler weather. Transporting already stresses the cattle, but additional heat increases the risk of early pregnancy loss.
Waiting for pregnancy diagnosis
In some cases, producers want to pregnancy check after artificial insemination, but Funston suggested waiting, noting “Losses are minimal after about 40 days, so at least wait 40 days after AI to pregnancy check.”
He added, “But then again, 40 days following AI, producers will have bull-bred cows that are going to be at risk for handling.”
Funston shared one case he worked on where a well-established heifer program lost about 15 percent of pregnancies after trailing heifers to summer grass. The operation pregnancy checked the heifers at 30 days pregnant, then trailed them roughly one mile in moderate temperatures.
“Any time an animal has a corpus luteum, which is formed after ovulation and is sensitive to prostaglandin, we run risk of pregnancy loss,” Funston explained for the reason of the loss. “This occurs after day six or seven of pregnancy until the animal fully establishes uterine apposition of the uterus and the placenta, which occurs around day 30. Roughly 10 days after this, the risk of pregnancy loss considerably decreases.”
Funston also shared data on pregnancy loss based on using ultrasound or palpation by way of pregnancy checking. Funston noted, when a skilled professional performed palpation, there was not any more loss than when using ultrasound.
“Ultrasounding is less invasive, and, because the fetus is not palpated, the stress on both the cow and the fetus is lowered,” said Funston. “These are just some of the big-ticket items I feel producers have control over in protecting pregnancy rates.”
Funston understands production is a balancing act and there will always be some risk involved when handling cattle, whether they are artificial inseminated or bred naturally. The success of pregnancy comes down to producers considering what works for their operation and an increased awareness of how situations may affect their herd.
Delcy Bayles is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net
