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SIOUX FALLS, S.D. - Vaccinations have become an increasingly important factor in keeping dairy calves healthy to turn them into profitable cows.

"With vaccines we've been able to raise the bar on disease resistance," said Dr. Tommy Zerse, Technical Services Manager for non-confined cattle for Intervet/Schering Plough Animal Health. "Without them, things such as ... 1,500 cow dairies would not be possible."

Zerse presented the seminar "Start life right: neonatal immunology and vaccinology" on April 2 during the Central Plains Dairy Expo. Zerse filled in for Dr. Scott Nordstrom, Manager of Veterinary Technical Services at Intervet/Schering Plough Animal Health, who presented the same seminar the previous day. Dairy farmers were able to take home tips and suggestions about on-farm vaccination programs.

Vaccinating a calf gives it immunity so it can live a long life and become a healthy cow, Zerse said.

"But there are risk factors along the way and there are a lot of things that need to go right," he said.

Four main factors that affect a vaccination program are vaccine handling, disease antigens, endotoxins and timing. Along with these, there are also other factors that could complicate calf vaccination: stress, disease challenges, balance of environment, parasitism, nutrition, colostrum and genetics.

With so many aspects to consider when vaccinating, Zerse said it's important to know how to decide what diseases to vaccinate against.

"We highly recommend developing a vaccine plan with your veterinarian," Zerse said. "All vets should be well educated on diseases we're facing out on the farm."

He also said it's important to protect against endemic diseases - diseases that are common in the herd or in the area. Two examples are BVD and Pasteurella. Using evidence-based medicines will help a farm be more efficient and economical. Zerse said many farms give calves vaccines for every disease. However, he said this makes the immune system work harder and may be costing the farm money.

"We need to ask, 'Do we need to vaccinate or can we manage around it?'" Zerse said. "The only way to know if it's needed is to go look for the evidence in your herd."

Having a written protocol will also make a vaccine program more efficient. Zerse suggests using a spread sheet to make it easier to follow dates of vaccinations.

"You might be vaccinating for something today you don't need to be vaccinating for one year from now," he said. "[With a written protocol] you can make changes and tune up vaccination procedures."

To determine the impact of the vaccination performance, Zerse said use readily available information such as how much milk cows are giving.

Zerse also talked about endotoxins and the effect of using too many endotoxins at one time.

"Endotoxins in large amounts will stimulate the same mediators in the body that will cause animals to go into shock," Zerse said.

Having too many endotoxins could also lower natural immunity, decrease blood pressure, increase respiratory rate and cause other sickness.

As a rule of thumb to prevent this, Zerse recommended giving no more than two gram negative vaccines at a time. However, if two or more are given, alternate which side the vaccine is given. Then wait an additional week before giving another vaccine. He also said don't give gram negative vaccines during stressful times such as weaning. Gram negative vaccines should not be given with vitamin and mineral shots or with antibiotics.

When administering a vaccine, timing is everything, Zerse said. Find the stress points and disease challenges and try to get resistance of animals up before those times. Zerse said it usually takes between two and three weeks to gain resistance.

"For diseases that are endemic on your farm, you need her to have immunity all the time," Zerse said.

Therefore, he suggested revaccinating every four to six months for endemic diseases.

Although vaccinations are important, nutrition also plays a big role in keeping calves healthy and making vaccinations work. Poor nutrition equals immune suppression, which will cause sick calves. In order to maximize vaccination response, prenatal nutrition, sufficient colostrum and quality calfhood nourishment is essential.

However, immunity has its limits.

"Disease challenges can overcome immunity," Zerse said. "Sometimes when calves are exposed to too much they will get sick."

Diseases such as salmonella, clostridials, E. coli and BVD are all examples that have broken through immunity. Zerse said management plays a big role in keeping calves healthy and disease-free.

"Good immunity can be overcome by poor management," Zerse said. "Weather you can't control, but there are other things you can manage."

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