DULUTH, Ga. — “In the dairy world, we tend to think of respiratory disease as a post-weaning event, but its reach goes much further than that,” said Mark van der List, DVM, Boehringer Ingelheim.

Bovine respiratory disease (BRD), or pneumonia, can impact every animal at every stage of life, and successful management involves a holistic, 360-degree approach. “When we invest in good BRD management practices, from birth to an animal’s last lactation, we’re going to see a high return on our investment. We’re protecting that animal’s lifetime performance and even its offspring’s lifetime performance,” explained Dr. van der List.

An ideal BRD control program can be broken down into three phases:

Phase one: Newborn

Respiratory disease affects calves earlier than producers may realize. In fact, it’s the source of 22.5% of deaths in unweaned heifers.¹ “The first, and one of the most important, forms of protection we can provide newborn calves is quality colostrum,” said Dr. van der List. “Colostrum defends calves against the most common viral and bacterial infections found within their environment.” Calves should receive four quarts of colostrum immediately after birth, followed by a second feeding eight hours later.

Giving high-quality colostrum is key — research shows that up to 60% of maternal colostrum fed to newborn dairy calves may be inadequate.² “To boost quality, start by focusing on dry cows,” advised Dr. van der List. “Ensuring dry cows are comfortable, in a low-stress environment and have proper nutrition will help them produce better colostrum. I also suggest giving a vaccine around dry off as it offers a dual benefit: It can keep the cow healthy and enhances her colostral antibody levels.”

Once calves have received colostrum, it’s time to start thinking about vaccination. Calves can be vaccinated as early as 3 days of age with intranasal vaccines and again at 30 days of age with injectable modified-live virus (MLV) vaccines. Antibodies absorbed from colostrum can interfere with the development of immunity from MLV vaccines for several months after birth, so it’s also important to administer an MLV vaccine proven to develop immunity in calves even in the presence of colostral antibodies.³

We also want to ensure newborn calves are kept in a stress-free, clean environment with good ventilation. If possible, keep calves from spreading respiratory disease by preventing nose-to-nose contact. If you are housing two or three calves per pen, it’s still important to prevent nose-to-nose contact between pens.

“Despite all producers do to keep calves healthy, we’re still going to see animals come down with BRD,” said Dr. van der List. “But we can get ahead of the problem with diagnostics. Identifying signs and diagnosing BRD early, almost when the animal is on the verge of getting sick, is when you’ll get the best treatment results.”

Early BRD diagnosis can be a challenge, but there are tools available that can help:

• An ultrasound can detect subclinical BRD cases, where producers can’t see visible symptoms. They can also evaluate the success of BRD management changes. Many veterinarians are trained in how to perform an ultrasound on lungs and can help identify these BRD cases earlier.
• Calf health scoring charts that utilize several clinical signs of BRD can help producers diagnose calves more rapidly and objectively. The University of Wisconsin and the University of California-Davis have printable charts that can be posted in a calf barn.

Ultrasounds and calf health scoring charts can be implemented at the preweaning phase but should continue to be used past weaning.

Phase two: Weaning

“Weaning is a high-stress, high-risk time for calves,” said Dr. van der List. “Three factors to focus on during this period are stocking density, diet and ventilation.”

• Controlling stocking density, and providing calves with enough space to eat, reduces stress and the spread of disease. “We don’t want newly weaned, vulnerable calves to go into very large groups right away,” advised Dr. van der List. “I suggest putting calves into groups of no more than 10 animals, and then gradually increasing the numbers over time.”
• Nutrition is a major component of avoiding BRD at any phase of an animal’s life, but especially when calves switch from milk to a roughage diet. If done incorrectly, calves can go into an energy deficit in which their immune system becomes compromised. “Producers will know something is off if they see newly weaned calves losing weight,” said Dr. van der List. “Switching calves to a roughage diet should be done gradually with the guidance of a nutritionist.” He or she can help determine the amount and type of feed needed to transition diets smoothly.
• “I can’t stress enough the importance of good ventilation for animals at every age,” said Dr. van der List. “Especially with indoor housing, if there is inadequate air exchange, bacteria build up and you’re going to see a rise in respiratory problems. Check with your veterinarian to ensure ventilation rates are appropriate for the time of year. The summer requires more air changeovers than in the winter.”

Phase three: Breeding-age heifers and cows

“Some of the same viruses that cause respiratory disease in calves also cause reproductive problems in cows and springing heifers,” explained Dr. van der List. “This is why continued vaccination is so critical.” Immunizing these animals with appropriate vaccines protects their respiratory and reproductive health as well as ensures the health of their newborn calf.

Although it’s not as common, adult cows and breeding-age heifers can come down with a case of BRD — usually during times of stress. Stress can suppress an animal’s immune system and open the door for viruses and bacteria to invade the lower respiratory tract. If your operation is seeing cases of BRD, talk with a veterinarian and discuss areas that may be potentially causing stress in your cows such as overcrowding, poor ventilation, nutritional challenges and the presence of animals persistently infected with bovine viral diarrhea virus.

BRD treatment considerations

When animals do need to be treated for BRD, keep the following in mind when discussing antibiotic options with your veterinarian:

• Ensure the antibiotic is labeled for your class of animals. Some BRD antibiotics can only be used in non-lactating cattle (less than 20 months of age).
• If diagnostics were done, work to find an antibiotic that’s labeled against the identified bacterial pathogen. If diagnostics were not done, then select an antibiotic based on general activity against Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis.
• Following the label is an essential part of successful treatment. Product labels contain important information, such as the correct route of administration and the dose needed based on the animal’s weight.

“A BRD control program is a sound investment to make at every phase of an animal’s life,” concluded Dr. van der List. “Get your program fine-tuned, or started, with the help of your local veterinarian.”

— Boehringer Ingelheim

For more articles on dairy, click here.

Comments