The length of the normal rest period is controlled from 40 to 60 days. It is recognized that more or less than this will reduce subsequent milk production. The environment is controlled when possible to promote comfortable cows. In California the main general concern is heat stress. Heat stress is a factor of temperature and humidity.
Depressed appetite is the primary cause of the reduced milk yield.
Heat stress generally affects high-producing cows more than low producers. Shades, fans, and misters are all measures to ensure animal comfort. 20 degrees F. Records are produced, used and updated daily . It has been said that when production is measured production will increase. Animal identification is seen as the heart of the records program.