During heat-stress conditions, an animal’s body temperature peaks about three to four hours after the outside temperature peaks, notes Vic Cortese, associate director of veterinary operations at Pfizer Animal Health.

Animals with an elevated temperature do not respond well to vaccination. “As the temperature goes up, immune response to a vaccine goes down,” Cortese says. Not only that, but vaccinating at high temperatures can result in adverse reactions to a vaccine.

Bottom line: “Remember to look at the temperature before you grab the needle to vaccinate,” Cortese cautions. Avoid vaccinating when the temperature exceeds 85 degrees Fahrenheit, he adds.