Bob Patrick, DVM, from Shamrock Animal Health Services Inc. in Georgia, says respiratory disease in dairy calves remains a large problem in the United States. The NAHMS 2007 Dairy study estimated dairy heifer mortality in the United States to be 7.8 percent for unweaned heifers and 1.8 percent for weaned heifers. The same study revealed that respiratory disease accounted for 22.5 percent of unweaned heifer mortality and 46.5 percent of weaned heifer mortality.

Veterinarians, he says, understand methods of prevention and treatment, but sometimes fail to completely understand the economics of respiratory disease. The high cost of heifer development and tight margins in dairy production make preventive measures critical. 

Producers, Patrick says, want to know three things: how do we stop this now, how much damage have we done, and how do we stop it from happening again. Stopping it now involves recognition, diagnosis and treatment. Lack of proper oversight of employees at this point will lead to faulty diagnoses, shotgun therapy, increased drug costs, reduced treatment success, and drug residue problems. 

Patrick says prevalence of respiratory disease in adult animals is almost nonexistent when illness is prevented in younger animals. Stopping it from happening again may require protocol changes, environmental and facility modifications, management and employee education, and monitoring.

Successful prevention strategies should be cost effective, but they must also require little “management energy." Patrick suggests getting employees to “buy in” to changes by involving them in the development of procedures and protocols. The most effective prevention strategies include passive transfer of colostral immunity, balanced nutrition, proper housing, and vaccination. 

  • Passive immunity: Colostrum administration must be timely, of adequate quality and quantity, and relatively free from bacterial contamination. Monitor the colostrum program using colostral IGG concentration testing, colostral culture, and serum total protein measurements. Assure adequate nutrition for the calf to feed its immune system and optimize growth. Calves that are provided passive immunity along with proper nutrition are much less likely to experience future respiratory disease.
  • Raise calves in environments that offer protection from the elements while providing adequate ventilation, access to feed and water, and room to grow. Patrick believes calf hutches for pre-weaned calves are a superior method of housing for disease prevention when compared to crates or calf barns. Group housing for older calves requires adequate resting, feeding, and watering space with attention paid to size variation within groups. Attempts by producers to cut housing costs usually result in poor calf health, which actually increases costs.
  • Patrick believes other prevention strategies should provide adequate protection so that vaccination of calves should not be necessary until at least three weeks of age. However, there has been evidence that calves can mount an immune response to some vaccines during the first few weeks of life. Producers should work with their veterinarians to determine whether to use vaccination in the neonatal period.