Last night, when I took his temperature, Pie had a small fever - 101.4. While I was grooming him, I felt that he was slightly warmer than normal to the touch - those of you with children will perhaps know what I mean - the "mom touch" that can tell a fever. I consider anything over 101 a fever. This was very likely a reaction to his rabies vaccination the night before. Horses who do have a reaction to this vaccination, according to my vet - and most horses don't - usually develop a mild fever about 10-12 hours after the vaccination, with the fever disappearing by 24 hours after. Pie was vaccinated about 7 p.m., so any reaction would have started to show at about 5 to 7 a.m. But he ate his breakfast and when I drove by the pastures about 8 this morning, he was out grazing with the others.
Even though he had a fever last night, and was just a touch subdued although far from depressed, Pie was eating and drinking normally, so he didn't feel too bad. Horses who have had Lyme and/or EPM (Pie has had both) are often immunologically sensitive and can have an inflammatory reaction that can sometimes reactivate some of their symptoms, not so much due to the active agent in a vaccine, but rather to the adjuvants that are included. Although his fever might have declined on its own, I gave Pie a 1,000-lb. dose of Banamine just to dampen any inflammation. Two hours later his temperature was back in the normal range - 100.5.
This morning, he looked very happy eating on the round bale next to Red. His temperature this afternoon was 99.2 - his temperature immediately prior to his vaccination was 99.3, so this is his usual temperature at the end of the day. I gave him another day off - if a horse has had a fever I usually try to give them 24 more hours off with a normal temperature before riding.