Strategic management, disease prevention and parasite control set replacement heifers up for lifelong productivity.
DULUTH, Ga. (October 7, 2025) — A heifer that calves late in her first breeding season is already behind—and likely to stay that way. “It starts a vicious cycle,” says Jordan Thomas, Ph.D., University of Missouri, “where she calves late, breeds late the next year, and eventually falls out of the herd.”
Whether producers are raising or buying their replacement heifers, focusing on strong herd management, disease prevention and parasite control is the foundation of a successful breeding herd and long-term profitability.
Calving windows and nutrition set the stage
Ideally, heifers should conceive their first calf at 15 months of age and calve by 24 months. Breeding early sets her and her future calves up for success.
“If we take the average eight calving seasons into consideration, an early-calving heifer who continues to calve in the first 21 days as a cow will give an extra one-and-a-half to two calves over her lifetime, based on the higher weaning weights of her early-born calves,”1 said David Shirbroun, DVM, Boehringer Ingelheim. “With the market prices right now, getting those heavier calves from a well-developed heifer is extremely beneficial.”
Good body condition and nutrition also play a critical role in accelerating reproductive maturity, managing stress and overall health.
“A body condition score of 6 at calving is critical,” shared Dr. Thomas. “We want heifers to have a smooth appearance, with fat depots around the tailhead and brisket. This extra cover serves as a savings account of energy that ensures heifers enter their first lactation period prepared for success while they continue to grow.”
Heifers with good body condition at calving breed back sooner, wean heavier calves and better withstand stress. “Animals are a little bit selfish,” said Dr. Shirbroun. “They’ll meet their own energy needs before supporting reproduction.”
Balanced diets and quality forage help heifers meet those energy demands. “If we send her into a negative energy balance, we can compromise her ability to become pregnant, even if she has a fairly acceptable body condition score,” Dr. Thomas explained.
Producers should collaborate with their nutritionist to formulate balanced diets that are tailored to their environment and herd goals.
Vaccination prevents reproductive disease challenges
A pre-breeding vaccine program is one of the most effective tools to protect heifer health and long-term productivity.
“With replacement heifers, we really need to protect them from reproductive disease,” stressed Dr. Shirbroun. “If these heifers are infected by any number of different diseases, that’s going to set them back, either from a growth standpoint or cause reproductive issues.”
Bovine viral diarrhea virus (BVDV) Types 1a, 1b and 2, infectious bovine rhinotracheitis, leptospirosis, trichomoniasis and vibriosis are all top concerns for the breeding herd. While there are many implications of each disease, all are commonly known to cause infertility, embryonic loss or abortion.
BVDV is particularly threatening to a herd. If a pregnant heifer is infected, the virus can pass to her fetus, resulting in a persistently infected (PI) calf. Many PI calves appear completely healthy and go easily unnoticed, silently spreading BVDV to susceptible herd mates and their future offspring.
To reduce the incidence of reproductive diseases and PI calves, Dr. Shirbroun recommends a five-way viral vaccine, such as EXPRESS® FP, which includes the Singer strain. “A vaccine with the Singer strain is proven to prevent the formation of PI calves due to BVDV2,” he said.
Control the negative impacts of parasites
Keeping parasites in check is one of the simplest ways to help heifers stay healthy. Taking away gut irritation or damage associated with parasites allows heifers to fully utilize nutrition, gain weight efficiently and reach reproductive milestones.
“Parasite control is important for all cattle, especially if they’re going to be on grass for a long period of time,” Dr. Shirbroun noted. “One of the best things we can do is give those cattle an extended-release dewormer like LONGRANGE® [eprinomectin]. If they’re on grass for three to four months, they’re going to have protection against parasites for the entire grazing season.”
He continued, “Oral, standard injectable or topical dewormers are great when we need to purge the system or provide around 30 days of therapy. But when producers have cattle out on grass for 120 to 150 days, an extended-release product can prevent reinfection of parasites, and provide continued protection to the bovine’s digestive tracts.”
To get the most out of any deworming program, work with a veterinarian to select the right dewormers for your region and parasite pressure, and work with them to conduct diagnostics like fecal egg count reduction tests to ensure your program is effective.
Herd development is a long game
“Heifer development doesn’t start at weaning—it begins before conception,” pointed out Dr. Shirbroun. “The only true way to set up a heifer to achieve 100% of her reproductive potential and longevity is to have influence on the animal before it is even conceived.”
He recommends producers manage cow health before and during gestation with balanced nutrition, disease prevention and parasite control. “Once the heifer is born, her development is not just a six-month process,” Dr. Shirbroun emphasized. “When done correctly, heifer development is about three years—from the time she’s conceived until she has had her first calf at 2 years of age.”
LONGRANGE IMPORTANT SAFETY INFORMATION: Do not treat within 48 days of slaughter. Not for use in female dairy cattle 20 months of age or older, including dry dairy cows, or in veal calves. Post-injection site damage (e.g., granulomas, necrosis) can occur. These reactions have disappeared without treatment. Not for use in breeding bulls, or in calves less than 3 months of age. Not for use in cattle managed in feedlots or under intensive rotational grazing. Pregnant women should wear gloves and exercise caution or avoid handling this product.
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