Respiratory disease in young dairy calves
We know that respiratory disease is the second leading cause of death in un-weaned heifer calves (scours is the first). Unfortunately, heifers that experience respiratory disease also continue to have performance problems later in life. To effectively address these problems, producers must consider both the determinant and predisposing causes of respiratory disease.
First what is the level of passive immunity being transferred unto the calf? Current guidelines suggest baby calves should receive high quality colostrum right after birth, 3-4 quarts within one hour and 3 additional quarts within twelve hours.
Quality of colostrum is important. Collecting colostrum under strict sanitary conditions is also vital to help minimize bacteria growth. Some producers are pooling colostrum to increase the diversity of pathogens the calf is exposed to. However, when doing this, one also needs to make sure not to use colostrum from Johnes-infected cows or first calf heifers. Secondly, storage of colostrum is important to minimize the growth of bacteria. Colostrum should be refrigerated or frozen as soon as possible after collection.
Pasteurization of colostrum has also shown in research trials not to impede immunoglobulin’s (IgG) availability while decreasing the total bacteria counts (Johnson et al. 2007). However, pasteurization should be done by heating the milk to 60 C for 60-120 minutes in a batch pasteurizer, which uses lower temperatures and longer heating time. This does not damage the immunoglobulin’s in the milk. Unfortunately, these types of pasteurizers can be quite expensive. Some producers will also use them to pasteurize their waste milk in order to offset the expense.
Cleanliness is critical to helping minimize risks. A clean and dry living environment is critical. Calves should not have shared housing with cows during the first week of life and should be removed from maternity pens as soon as possible. Cleanliness of the calving pen
is also important to reduce microbe concentration.
We know that raising calves in barns is convenient and protects both the calves and employees from the environment. However, there are environmental risk factors that need to be addressed.
The following should be used as a guide to reduce respiratory disease when using calf barns:
· Reduce microbial contamination in the pen via adequate sanitation.
· Increase pen area (ideal: 32 square feet per calf).
· Avoid nose-to-nose contact between calves (solid separation panels if possible).
· Increase bedding depth.
· Use cold-temperature housing.
· Provide adequate ventilation while reducing drafts.
· Provide additional nutrients via calf starter in cold-temperature housing.
We are assuming that calves have received adequate immunity via colostrum, so the next step is to reduce the microbial challenge. This means removing the calf from the dam as soon as possible. Calves should then be placed in their own individual pen avoiding nose-to-nose contact with other calves.
Vaccines are now being marketed for prevention of clinical respiratory diseases. Traditional views have held that the antibodies calves receive through colostrum usually inactivate the vaccines administered to them. More recent research indicates that, in certain instances, modified live viral vaccines stimulate a protective response in calves challenged with these agents. As example of this protection is the use of intranasal IBR/Pi3 vaccines in calves less than 1 month old (Garcia & Daly, 2010). Vaccine programs for calves against respiratory disease should be developed in consultation with your veterinarian.
To learn more about the topic of respiratory diseases in baby dairy calves and to learn to apply a scoring system to calves with respiratory disease please refer to the publication Respiratory Diseases in Young Dairy Calves by SDSU Extension Dairy Specialist Alvaro Garcia and SDSU Extension Veterinarian Russ Daly.
· Garcia, A. & Daly, R. (2010). Respiratory disease in young dairy calves. Brookings, SD: South Dakota Board of Regents, South Dakota State University.
· Johnson, J. L., et al. (2007). The effect of feeding heat-treated colostrum on passive transfer of cellular and humoral immune parameters in neonatal dairy calves. Journal of Dairy Science, 90: 5189-5198.