RISK-FACTORS ASSOCIATED WITH THE INCIDENCE OF FOAL MORTALITY IN AN EXTENSIVELY MANAGED MARE HERD

The purpose of this study was to determine the incidence of neonatal m ortality in a large, extensively managed mare herd and what risk facto rs were involved in foal mortality. For a 6 wk period between April 18 , 1994, and May 31, 1994, 334 foals were born, of which 74 died before reaching 10 d of age, giving an overall mortality of 22% for this per iod, Seventy four percent of the foal deaths occurred within 48 h of p arturition. The major causes of foal mortality included starvation/exp osure 27%, septicemia 26%, and dystocia 20%. Weekly incidences varied significantly, ranging from 67% for week 1 to 14% for week 5 (P < 0.01 ). Other risk factors that were associated with foal death included fa ilure of passive transfer (P < 0.0001), poor mothering ability (P < 0. 0001), the presence of dystocia (P < 0.0001), low birth weight (P < 0. 05), lack of rainfall (P < 0.01), and low temperatures (P < 0.1). The effect of sire, mare age, mare body condition, and foal sex were not s ignificant risk factors for foal survival (P > 0.1). Further studies a re required to determine if changing management procedures will be eff ective in reducing the incidence of neonatal foal mortality in this ex tensively managed herd.