EFFECTS OF STABLE FLIES (DIPTERA, MUSCIDAE) AND HEAT-STRESS ON WEIGHT-GAIN AND FEED CONVERSION OF FEEDER CATTLE

Stable flies, Stomoxys calcitrans (L.), and heat stress are known to a ffect feeder cattle weight gains. This study was conducted to determin e if a combination of heat stress and stable flies would create a syne rgistic or additive effect on weight gain performance of feeder cattle . In year 1, neither a 3-degrees-C increase in temperature coupled wit h an increase of 6% relative humidity nor an average of 6 stable flies per leg effected feeder cattle weight gains but a combination of the two treatments did reduce weight gains significantly (P < 0.05). In ye ar 2, treatments of a 2-degrees-C increase in temperature coupled with a 10% relative humidity, an average of 13 stable flies per leg, and a combination of the two treatments all significantly reduced feeder ca ttle weight gain (P < 0.05).