Rectal temperatures should be taken only when the sow is resting. Always make sure the thermometer is inserted its full length into the rectum.
A sow’s normal temperature is less than 101 degrees Fahrenheit pre-farrowing and less than 103 degrees Fahrenheit post-farrowing. Temperatures may rise due to milk production, tissue breakdown during farrowing, trauma to tissue or bones, or infection.
An elevated temperature in a sow that has not farrowed is anything greater than 102 degrees Fahrenheit and for a sow that has farrowed it is anything greater than 103 degrees Fahrenheit.