You’ve got a lot of money tied up in them, so picking the right bull is critical. That’s going to cost even more out of your pocket.

What about risk management? Not the kind of risk management that requires a banker or a commodity broker, but the kind that reduces risk from reproductive disease losses.

Thinking about all the possible disease organisms or conditions that cause reproductive losses in heifers, the list would be longer than the line of long-lost relatives showing up at your door after you just won the lottery.

Using every vaccine available over and over again in an abundance of caution doesn’t really provide an advantage; it just increases your costs and makes the heifers not want to work through a chute.

Given all those considerations, there are a few rules to follow for developing and improving your reproductive health program.

Reduce the risk of exposure

Most heifers haven’t been exposed to many disease organisms, so you need to take some necessary precautions.

Pulling potential replacements from a feedyard or putting them together from auction barns before turning in the bulls should be your last choice. Too much risk is involved.

Running heifers after weaning next to stockers, or particularly during the early breeding season, isn’t a good idea either, as the risk of IBR and BVDV infections greatly increases.

Manage yearling replacements as a separate breeding unit to minimize exposure to other cattle and the risk of disease organism exchanges. In this day and age, test heifer bulls for Tritrichomonas foetus (Trich) infection before using them.

Consider pre-breeding vaccinations

Pre-breeding vaccinations are used to protect the first pregnancy, to establish a degree of immunity that can be carried into adulthood and to avoid known, recognized vaccine side effects.

A pre-breeding vaccination program targets 10-month-old to 12-month-old heifers. This population makes ideal candidates for maximal vaccination response as they are low-stress, generally on a positive plane of nutrition and are not pregnant.

When considering overall reproductive disease risk management, a herd should be considered partially susceptible to viral diseases at all times.

Individual animal variation in response to previous vaccination, the removal of immune animals and the introduction of unvaccinated or susceptible animals account for this development.

Pre-breeding heifer vaccinations using either killed or modified-live viral (MLV) vaccines allows for the introduction of a high percentage of immunized replacements into the cow herd annually. Pre-breeding vaccinations are frequently seen as boosters to vaccines administered at weaning.

However, results from the latest NAHMS survey of beef operations show that less than 25 percent of operations vaccinated replacement heifers from weaning through pre-breeding.

This newly developed immunity, either from primary or booster vaccination, may not ensure lifetime reproductive protection in all vaccinated animals.

Modern MLV vaccines provide protection against early gestational viral challenges, minimizing the risk of persistently infected BVD calves and infertility and embryonic losses from IBR while providing fetal protection up to calving.

Intranasal IBR vaccines produce a response capable of providing protection through at least the first pregnancy. In endemic areas, or where a higher risk of exposure to IBR and BVDV exists, vaccinations should be repeated annually pre-breeding with MLV products or, if justified by the level of risk, a killed product can be used at pregnancy examination in mid-bred to late-bred animals.

Besides viral vaccines, several other types of vaccines may be used in replacement heifers pre-breeding. According to the NAHMS report, about 60 percent of calves receive clostridial vaccines through weaning.

Know the booster schedule

While not a traditionally accepted reproductive pathogen, a revaccination pre-breeding would be recommended for all clostridial species frequently found in your locale.

Prior vaccination for clostridials does not appear to interfere or affect responses to either the clostridial bacterins or the toxoid components of most vaccines.

Pre-breeding vaccinations using leptospiral bacterins should offer protective antibody levels during pregnancy but should be boostered at pregnancy check in heifers to provide protection through late gestation.

Like clostridial vaccines, leptospiral vaccines are termed multivalent in that they contain several components or serovars. Cross-protection between serovars is of little benefit in preventing infection.

Therefore, serovars should be selected based on reported serovars in the area in which your herd is located. Campylobacter fetus vaccination provides the most practical method to control the disease. In endemic herds, replacement heifers provide the highest at-risk population.

Pre-breeding vaccinations should be followed by booster vaccinations immediately before the start of the breeding season to provide the highest degree of protection.

Like many of the Campylobacter vaccines, Tritrichomonas vaccines, if used, need to have a primary vaccination followed at minimum two to four weeks later with the booster vaccination that is timed to be given a month before breeding begins.

Most Tritrichomonas control programs focus on reduced exposure risks by using virgin bulls, tested bulls or AI on replacements. No vaccine is currently available to aid in preventing Neospora canium, a parasitic disease frequently seen in Texas and Oklahoma as a late-gestational pregnancy loss in heifers and cows.

Practice good parasite management

So your vaccination program isn’t compromised – internal and external parasite control should be practiced. You are paying to get the most nutrients out of the pasture for a breeding set of heifers.

Deworming yearling heifers prior to the start of the breeding season lowers parasite loads in both the group of heifers and on pastures they are assigned.

Beginning early in the breeding season and lasting through the end of breeding season, practice good fly control to reduce fly counts. This practice aids in lowering pinkeye cases and helps minimize weight losses associated with high fly counts.

Reproductive disease control programs for replacement heifers don’t have to be complex or expensive. Just as with a good trapeze act, timing is everything.

Time the administration of vaccines and other management procedures to follow the manufacturer’s recommendations for its vaccines or products, since not all are the same.

It also is important to time their administration to get the maximum protection at the start of the breeding season and to avoid side-effects of certain types of vaccines as mentioned on the product label. Know your vaccines, particularly if they need boostering prior to breeding or during gestation to get optimal protection.

Practicing good risk management decreases the opportunity for reproductive disease agents to enter your herd or rapidly spread, causing great damage if inadvertently introduced. Protect the investment you made in your replacements and enjoy the reward of a successful program next calving season. 

Mark Spire is a beef technical services manager for Merck Animal Health. He lives in Kansas and can be contacted by email or (785) 537-3857.

Reproductive rules for heifer health management

• Work with your veterinarian to develop an effective vaccination program for your herd.
• Follow manufacturer’s recommendations for product use and administration.
• Manage replacement heifers as a separate breeding group to reduce risk of exposure.
• Target 10-month-old to 12-month-old heifers for pre-breeding vaccinations.
• Follow up with needed booster vaccinations immediately before the start of the breeding season.
• Consider viral vaccines that provide BVD and IBR protection during the entire gestational period.
• Select vaccine components that coincide with reported pathogens in your area.
• Practice good management practices for deworming and fly control.