Published online by Cambridge University Press: 02 September 2010
Non-genetic sources of variation in pre-weaning death losses due to enteritis or pneumonia have been investigated using records of 15,329 rabbits born during the years 1946–61 in the random bred colony at the U.S. Rabbit Experiment Station at Fontana, California. Under consideration were periods of years, season within years, litter size, parity of doe, and fostering.
For enteritis there was a statistically significant effect of season due to a negative regression of death rate on ambient temperature. For pneumonia, periods of years were statistically significant due to an increase in later years in deaths during the first 14 days of life. The other sources of variation studied were of negligible importance.