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 perform poorly later in life. To effectively address these problem producers must consider both 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 bacterial growth. Some producers pool colostrum to increase protection from a wider diversity of pathogens the calf might be 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 140 ° F (60°C) for 60-120 minutes in a batch pasteurizer, which uses lower temperatures and longer heating time which does not damage milk immunoglobulin’s s. Unfortunately, these types of pasteurizers can be quite expensive with some producers using them also to pasteurize their waste milk in order to offset this expense.
Cleanliness is very important to help minimize risks; a clean and dry calf 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 bacterial concentration.
We know that raising calves in barns is convenient and protects from the weather both calves and employees. 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.
If calves have received adequate immunity via colostrum, 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 individual pens 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 against respiratory disease in calves should be developed in consultation with your veterinarian.
To learn more about respiratory diseases in baby dairy calves and how to use a scoring system to identify calves with respiratory disease please refer to Respiratory Diseases in Young Dairy Calves authored by Alvaro Garcia and Russ Daly.