A normal rectal temperature for an adult horse at rest is 37.5°C to 38.5°C, while foals can be slightly higher, up to about 38.9°C.
A high temperature, above 38.5°C, can be a sign of fever caused by infection (viral, bacterial, or fungal), inflammation, heat stress or heat stroke, colic, certain metabolic disorders, or other systemic illness. In foals, a high temperature can also indicate conditions like neonatal sepsis.
A low temperature, below 37.5°C, can indicate shock, severe blood loss, advanced illness, hypothermia, or circulatory collapse. It’s often a sign of a critical emergency and requires immediate veterinary attention.
Seek advice from your veterinarian if you notice an abnormal temperature in your horse. This should also be assessed alongside other symptoms such as lethargy, loss of appetite, changes in heart rate or breathing, sweating without exercise, or signs of pain. Always contact your vet if you’re concerned.