The health of your calves begins before conception. Calves born to mothers with nutritional deficiencies and low-body condition scores, or to those with disease concerns, are, at best, not going to show the growth and reproductive potential of those born to healthy mothers. Maternal illness can mean calf mortality. Having disease occurrence in your herd impacts overall herd health and decreases your reproductive efficiency. It’s a downward spiral.
Vaccination increases the antibodies present in colostrum, and protects the fetus in utero. When properly timed, administered and monitored, a vaccination program can positively impact reproduction success and overall heard health.
Vaccinations can decrease the number of animals shedding pathogens, decrease the quantity of pathogens in the herd and decrease the shedding period. Through this reduction in pathogen numbers, the herd becomes less likely to suffer disease, Vaccination is all about gaining control over the pathogens present in a herd.
“It’s important to talk about how vaccination can lend a hand in limiting those losses,” Kathy Larson, beef economist with the Western Beef Development Centre (WBDC) in Canada, said referring to calf death loss. Larson, along with Dr. Nathan Erickson, University of Saskatchewan, spoke in a recent webinar production on economical vaccinations of beef herds.
Researchers at WBDC implemented a vaccination program for their research herd in 2016, which included protection against clostridial diseases; bovine viral diarrhea (BVD); infectious bovine rhinotracheitis (IBR); parainfluenza 3 (PI3); anthrax; and bovine respiratory syncitial virus (BRSV) for all herd groups, with vaccination occurring in June. The calves – all born in May – were vaccinated again in September. Cows were protected against scours in March. Bulls were vaccinated against footrot in May. In the fall, cows and bulls received ivermectin for parasite control.
Not vaccinating the herd pre-breeding can cause abortions, open cows, stillbirths and ongoing reproductive issues in the herd. While producers often skip pre-breeding vaccinations, the cost of reproductive losses in the herd is normally much more expensive than preventative treatment. Overall costs associated with foregoing pre-breeding vaccinations include the loss from reduced birth rates, treating sick animals, delayed conception rates and overall decreased herd health.
Compared to the losses from disease, the cost of the herd vaccination program is nominal, she said. Larson estimated the vaccination protocol at WBDC costs approximately $25 per cow overall with good results on herd health.
“We treated 27 cows – a total of 33 times – which presents 8 percent of our cow herd,” Larson said. Only two bulls required treatment, as did 13 percent of the calf herd on this vaccination protocol. “I encourage every producer to work with their vet to determine a vaccination protocol that works for your operation.”
Disease and reproduction
For closed herds, where no members – including bulls – are purchased, a vaccination program should include IBR, BVD, PI3 and BRSV. Adding vaccination against leptospirosis and vibriosis (venereal diseases) is important in open herds, according to Erickson from Veterinary Agri-Health Services.
According to 2015 data from the Western Canada Cow/Calf Survey, only 69 percent of beef producers vaccinated their females prior to breeding. In 2008, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) conducted a survey that showed that calves aged 22 days through weaning were most likely to be vaccinated against various diseases of concern, with about 60 percent of the operations having done so. But pre-breeding vaccinations for leptospirosis was only performed on 31.7 percent of operations; 28.1 percent of operations vaccinated for BVD in cows; and less than 25 percent were vaccinated for IBR. Bulls were only vaccinated in less than one-third of the operations. The USDA has been conducting a similar study of beef herds this year.
Viral diseases in beef herds include BVD, PI3, BRSV and IBR. These commonly cause illness in calves, but vaccinating heifers and cows pre-breeding, as well as calves, can provide enhanced protection to the herd. According to Larson, data indicates that “losses can be substantial,” up to $25 per cow, per year, in herds with persistently infected (PI) calf with BVD. In herds with PI calves, pregnancy rates can be 5 percent lower, compounding economic loss.
Veterinarian Gregg Hanzlicek of Kansas State University Veterinary Diagnostic Laboratory presented “Reproductive and Other Emerging Disease Concerns” at the 2017 Applied Reproductive Strategies in Beef Cattle conference. PI calves become an issue when exposure to BVD occurs within the period of 40-100 days of gestation. For seronegative breeding cows exposed to PI calves, those that become seroconverted before breeding had pregnancy rates of 79 percent. Those seroconverted during breeding had a 44 percent pregnancy rate, and those who did not show immunity until after breeding only had pregnancy rates of 22 percent, according to one study, he said.
Bacterial diseases can also cause reproductive issues. Leptospirosis commonly causes abortions, stillbirths or sickly calves. With this disease, abortions typically occur later in pregnancy. There are numerous strains of leptospirosis, and immunity is not long-lasting, so protection can require immunization both at pre-breeding, and at pregnancy check. The disease sheds via the urinary tract, genitals and mammary gland. Infected pregnant cows may not show signs of illness. The disease can be transmitted via rodents, dogs and other wildlife and wet conditions favor its persistence.
Vibriosis, caused by Campylobacter fetus, is commonly carried by bulls. During breeding, it is passed to the cow and causes inflammation of the reproductive tract and can cause pregnancy loss. Although cows will shed the infection within a few weeks, it persists in bulls and while infected, cows can transmit the disease to other bulls.
Anaplasmosis – a bacterial disease transmitted by insect vectors or needle sticks – is another cause of abortions. Infected mothers become so anemic that calves are deprived of oxygen and aborted. It can also by transmitted to the calves in utero, typically causing late-term abortions or stillbirths.
Brucellosis, another infectious bacterial disease, is causing increasing concern as this disease remains highly contagious in aborted fetal tissue, and has been making a comeback as a human illness. Infected cows remain infected, and while subsequent pregnancies do not typically end in abortion, calves born are sickly.
The protozoa Neospora caninum causes neosporosis, which is difficult to treat and causes congenital infections if the pregnancy does not end in abortion. Calves born to cows infected will have the disease present at birth. These calves tend to have future reproductive problems. The organism can persist in the environment for months, and is carried by canines.
The venereal disease trichomoniasis is another abortion-inducing reproductive concern. Infected bulls remain infected for life, but no outward signs or negative effects are normally found. Infected cows show no signs of disease, except perhaps a vaginal discharge, but embryonic death is common.
Vaccinations don’t provide immediate protection. They need several weeks to take effect, so timing is critical. For booster shots, two weeks provides sufficient immune response, but for those animals receiving the vaccination for the first time, four weeks is required, Erickson said.
Annual vaccination, one month prior to breeding, is the standard recommendation. For some diseases, a follow-up vaccine may be needed as well. Timing vaccinations that cause reproductive concerns to be given pre-breeding can help to increase their efficacy over solely immunizing at pregnancy check or pre-calving. Veterinarians familiar with your herd and with localized disease pressures are the best resource for an effective pre-breeding vaccination protocol.
“There is a potential for a missed opportunity” if vaccination is not completed at the primary time for effectiveness, Erickson said. “What’s important on this pre-breeding shot [is that], we have the maximum immunity in this cow during the high-risk period.”
While timing is everything for reproductive vaccines, vaccine handling is extremely important, too. Vaccine temperature needs to be consistent, and vaccines should be stored on the middle shelf of the refrigerator. Using a properly cleaned syringe, administering vaccinations in the proper injection site and in the correct dosage, are also key to effectiveness. Needles should be changed every time before refilling and after every 10 animals.
Vaccines can include either a killed organism or a modified live version of the pathogen. As per Hanzlicek, abortion trends in beef cattle show that during 2014, many bacterial abortions from IBR were from strains identical to those utilized in modified live vaccines (MLV), possibly due to producers not carefully following label directions. For pregnant cows, some veterinarians prefer killed vaccinations.
Stressed animals will not respond as well to vaccinations as those who are less stressed during vaccination. And animals that are already infected with the pathogen will not respond as expected to the vaccine.
Because many common diseases of cattle can cause abortion or infertility, optimizing your herd’s performance means implementing an effective vaccination protocol, including important pre-breeding vaccines. In addition to providing protection against reproductive losses, the proper timing of these vaccinations will pass immunity from mother to calf, getting calves off to a healthier start, too.