A SURVEY OF THE CAUSES OF MORTALITY IN ADULT MINK, WITH EMPHASIS ON THE LACTATION PERIOD

A study of the pattern and relative frequency of diseases in adult fem ale mink during the lactation period was undertaken. All adult females that died between parturition (April/May) and July 1, 1990, from 48 f arms in southern Ontario were selected for study, and the cause of dea th was determined by gross necropsy. In addition, the cause of death w as determined by gross necropsy for all adults and weaned kits that di ed on one farm between April 1988 and March 1989. The mortality rate a mong farms in the 1990 study, for adult females during the lactation p eriod, ranged from 0.2% to 10.1%, with a median of 1.90%. Nursing dise ase (56%) was the most common diagnosis, followed by mastitis (11%), m etritis (8%), and dystocia (7%). Escherichia coli and Staphylococcus s pp. were the most frequent isolates from the cases of mastitis. In the 1988/1989 study, the mortality rate was highest from May to July, wit h a large increase in June as a result of nursing disease.