“Take an organized approach to elucidate causes of fever of unknown origin in the foal,” said Robert Franklin, DVM, Dipl. ACVIM, of Goulburn Valley Equine Hospital in Victoria, Australia, during the Western Veterinary Conference held February 15-19 in Las Vegas, Nev.

Normal foal body temperature is up to 102°F, he said, and it can be elevated by infectious and non-infectious factors. Infectious causes include bacteria (the “default” diagnosis), viruses (often rotavirus), and fungi. Non-infectious causes might be neonatal isoerythrolysis (NI, or jaundice), a reaction to a transfusion, hot weather, transport stress, exercise, certain medications (particularly macrolides, including erythromycin and azithromycin), hypothalamic problems, and muscular disorders such as white muscle disease (muscle damage and weakness caused by Vitamin E and/or selenium deficiency)