Health Care for Weaned Calves
Article reprinted with the permission of The University of Tennessee Extension Service.Dr. Fred Hopkins
Professor and DVM, The University of Tennessee
Sickness in calves is often seen around the time of weaning and is most often associated with stress. A sound vaccination program and appropriate health care for sick calves will result in fewer and less severe problems. Pneumonia in calves is the most frequent disease diagnosed in calves. At slaughter, about 1/3 of all calves showed some evidence of having had pneumonia. Most of these cases of pneumonia were never diagnosed, but resulted in poorer growth performance and decreased resistance to other diseases.
The calf is more susceptible to pneumonia than other animals due to their having a small rigid larynx which is easily injured. Also, the calf’s windpipe is short and small making it easier for germs to get to the calf’s lung. Finally, the calf’s lung is formed in a way that makes it harder for the calf to clear out germs once they get into the lung. Pneumonia in calves is often referred to as “Shipping Fever” since most cases are seen within the first month after the calf is subjected too a large amount of stress such as shipping.
Common stressors in calves include weaning, shipping, castration, dehorning, exhaustion, and hunger. The calf’s body is less able to fight off various infections when the calf is stressed. A number of viruses can easily infect the stressed calf. The IBR, BVD, PI3 and BRSV viruses commonly infect the windpipe of stressed calves. The virus can produce disease on their own and also reduce the ability of the of the windpipe to keep bacteria from getting into the lung. Once bacteria, such as Mannheimia hemolytica get into the lung, pneumonia results.
Since weaning is a very stressful time in the calf’s life, proper weaning management can be important in preventing sickness in calves. Calves are best confined to a small drylot for the first month after weaning or shipping. They can find feed and water more easily, and observation and treatment for disease is less of a problem. This small lot should have shade and a windbreak. The water tank should be filled only after the calves are in the pen so that they can hear the water running. This makes them much more likely to find the water and drink it.
The feed bunk(s) should be long enough to provide 1½ feet of linear space per calf so that there is plenty of room available when they eat. In addition to grain, calves should be fed grass hay free choice. The calves should be observed for sickness several times daily and treated when signs or sickness develop.
With calves that are very stressed and likely to get sick, metaphylaxis can be used to decrease losses. Metaphylaxis refers to the use of antibiotics in all of a group of animals where disease is believed likely to occur. Antibiotics used for metaphylaxis can be given by injection or in the feed. Two injectable antibiotics are cleared by the FDA for metaphylaxis in calves, tilmicosin and florfenicol. Both are generally given at the time of weaning or after shipping. Chlorotetracycline is the most frequent feed additive antibiotic used for metaphylaxis in calves.
Animal Health Products for Calves
Vaccines are commonly given to calves at weaning to help prevent disease. It is important to remember that useful immunity may take days or weeks to develop after vaccination. Therefore, vaccinating calves a month or more before weaning will provide immunity when the immunity is needed most. Vaccines most frequently used in weaned calves are: IBR, BVD, PI3, BRSV. These virus are commonly associated with pneumonia in calves. Many brand names and combinations are available. Both killed and live vaccines are available and, if used properly, are effective. Killed vaccines are considered to be very safe to use in most calves. Newer killed vaccines have been developed which work very well. However, several weeks may go by before the calf develops maximum immunity. Modified live vaccines produce immunity quicker but may not be as appropriate in stressed or sick calves. However, it is important to remember that the big problem in calves not vaccinated are improperly vaccinated rather than which vaccine is used.
Blackleg vaccine (usually 7-way) should be given to these calves unless they have been given it recently.
- Hemophilus and Pasteurella vaccines may be of some help in specific situations.
- Leptospira (lepto) vaccines maybe appropriate for weaned calves and the 5-way vaccine is most frequently used.
- Vitamin A, D, and E injections are sometimes recommended.
- Virtually all calves will show increased weight gains if dewormed at weaning.
Identifying Sick Calves
Generally, the sooner a calf is treated, the more likely it is to recover. Calves with pneumonia will often be found standing alone with a lowered head, droopy ears and half-closed eyes. They will be breathing faster than normal and may have a dry muzzle. Calves with pneumonia may or may not cough or have a runny nose. Affected calves may be stiff and have diarrhea. Most will have a fever.
Treatment of Calves with Pneumonia
Calves with pneumonia are best treated with antibiotics. A number of antibiotics are available for this purpose. The newer antibiotics available only by veterinary prescription are more expensive but more likely to be effective than older antibiotics available over-the-counter. If the antibiotic being used is effective, then the treated animal should make a definite improvement within 24 hours of treatment. For instance, the body temperature of a calf treated successfully should fall at least 2EF within 24 hours of treatment.
Weaning time is a stressful time in a calf’s life when sickness is likely to occur. However, with good management and the proper use of animal health products, problems should be minimized.
References and Contact Information
This article originally appeared in the Southeastern Expo '04 Farm and Home booklet and has been reprinted with permission from Mr. Milton W. Orr, Extension Agent, The University of Tennessee Extension Service - Greene County.