Summertime stressors like high heat and humidity can reduce a calf’s response to vaccines. Sam Leadley, calf-care specialist with Attica (N.Y.) Veterinary Associates, offers these tips for vaccinating in the summer:

1.  Vaccinate early in the morning when heat stress is lowest. 

2.  Keep vaccines out of direct sunlight.

3.  Keep vaccines cool.

4.  Put killed vaccines back in the refrigerator.