Spring turnout to the pasture is a good time for producers to review their cow-calf health management plans, according to North Dakota State University Extension livestock experts.
They note that a number of factors can impact cow-calf health, including slow grass growth and moisture conditions that may delay grazing readiness and result in prolonged feeding. Other factors are cooler, wet conditions that create a variety of challenges for young livestock, particularly for those in drylots or areas with high concentrations of livestock.
“The passive transfer of immunity from the dam is dependent on the availability of high-quality colostrum containing adequate levels of antibodies, as well as protein, energy, vitamins and minerals,” says Janna Block, extension livestock systems specialist at NDSU’s Hettinger Research Extension Center. “Environmental stress at the time of birth, combined with low-quality feedstuffs, may have reduced the quality and quantity of colostrum available to newborn calves.”
Colostrum is a form of milk that cows produce in late pregnancy. It contains energy, protein, fat, vitamins and antibodies to protect newborns against disease until their own immune system is functional.
The environmental and feed quality issues related to colostrum, nursing and passive transfer of immunity create an increased risk for bacteria and other pathogens that can cause scours and other health conditions even beyond the first few months of life.
“In addition to managing current health problems, producers need to start thinking forward to health insurance programs for nursing calves on pasture,” says Gerald Stokka, extension veterinarian and livestock stewardship specialist. “For spring-calving herds, branding or turnout time is a good opportunity to protect the calf through the summer grazing period with appropriate management. One of the important components of the health insurance plan is vaccinations.”
Risks to calves include respiratory diseases (summer pneumonia), clostridial diseases, pink eye and foot rot. Stokka encourages producers to work with their veterinarian to evaluate which vaccines to use based on three principles:
- Are vaccines necessary? Is the risk of the disease significant?
- Are vaccines effective? Does evidence show that the vaccines work under field conditions?
- Are vaccines safe to use? When used according to label recommendations, the risk of systemic and local tissue reactions is limited.
Veterinarians generally recommend administering a five-way modified live-virus vaccine to calves at turnout time. This vaccine usually includes protection against infectious bovine rhinotracheitis (IBR), PI3, bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV).
The principle is to provide some protection during the nursing phase and also to begin the immunization of not only individuals but groups of animals to build herd immunity. While the immune response in young animals is somewhat limited, this initial or primary dose provides immune system memory for a booster dose to be administered prior to or at weaning.
Vaccination for calves against BVDV at turnout may not be necessary in operations that have biosecurity procedures and practise annual cow herd vaccination for BVDV. Instead, producers may consider using a modified live-virus intranasal vaccine to combat infectious IBR, PI 3 and BRSV, or a simple subcutaneously administered three-way modified live-virus vaccine.
Here are the specialists’ assessments of other vaccines:
The use of vaccines to reduce the risk of Mannheimia hemolytica and Pasteurella multocida is common. Protection against these bacteria often is included in combination with five-way modified live-virus vaccines.
An inexpensive, effective vaccine is available against the clostridial family of diseases more commonly called “blackleg.” This vaccine commonly is called a seven-way, indicating protection against seven different species of clostridial bacteria and toxoids in the vaccine.
Pink eye vaccines are available in the commercial market, and the opportunity to create a herd-specific autogenous vaccine is available. However, evidence of their efficacy is lacking. Fly control, rotational grazing, early treatment and separating infected animals from the rest of the herd help reduce the spread of pink eye. Foot rot vaccines have been shown to have approximately 50 per cent efficacy in reducing foot rot disease. However, pink eye and foot rot vaccines require at least two doses to produce some level of protection.
Dewormers may be necessary in some grazing situations; however, dewormers administered prior to the grazing season will offer little benefit for internal parasite control. Some fly control is achieved with the avermectin products through the control of larvae developing in manure patties. But do not use avermectins strictly for fly control because resistance will develop rapidly.
“When using inactivated vaccines to prevent respiratory disease, consult with your veterinarian as to their effectiveness and whether booster doses will be necessary,” Stokka advises.
The specialists caution that many products on the market claim to boost the immune system or promote gut health. However, few of these products have been evaluated in a research setting, and producers should consult with their veterinarian about using the products.
Good stewardship also applies to calf processing procedures and reducing stress on the animals and people, the specialists say. They recommend producers:
- Make sure vaccine delivery instruments are in good repair, don’t leak and deliver the right amount.
- Provide ways, such as vaccine coolers, to keep vaccines at the proper temperature.
- Make sure they have enough needles to allow for frequent changes, and if using intranasal vaccines, have an adequate supply of intranasal cannulas to change for every calf or at least every five calves.
- Walk through the handling facilities before working cattle, and repair breaks, brace weak spots and make changes if cattle flow is less than expected.
- Change handling procedures if hollering, screaming, hand waving and running to move cattle and people are part of their normal working procedures.
Protect people too
Providing protection for people during this working season also is very important. Working cows and calves requires a specific number of people to do the job efficiently, quietly and carefully.
Due to some risk of virus transmission from person to person, limit the number of individuals to only those who are necessary to perform the work. Inform others who like to show up for social reasons that this year is different, and if someone has been ill, that person should stay away from this year’s calf processing event.
“With challenges experienced this spring, now is a good time to evaluate current vaccination and herd health management protocols and adjust if necessary,” Stokka says. “Developing strategies to improve calf health during the grazing season is key in ensuring desired performance and preparing the calf’s immune system for weaning. It also is important for producers to keep in mind additional challenges this spring to complete these tasks while ensuring that everyone stays safe and healthy.”