Effects of Niacin and Aspirin on Performance Parameters in Heifers Fed Endophyte-Infected Tall Fescue

Abstract

Cattle grazing endophyte-(Acremonium coenophialum) infected tall fescue perform poorly because of the adverse effects of endophyte toxicosis. One of the manifestations of this toxicosis is elevated body temperature caused by an inability to dissipate body heat Niacin has vasodilatory activity and has shown a beneficial heat dissipation effect in some animal species. Aspirin affects body temperature via prostaglandin synthesis and may be beneficial in alleviating high body temperature induced by consumption of endophyte-infected fescue. To evaluate these two compounds, 20 beef heifers, stratified by weight, were allotted to one of four treatments: LE: low-endophyte fescue hay HEC: endophyte-infected hay (70% infestation rate), HEN: endophyte-infected hay plus 2g niacin/d, and HEA: endophyte-infected hay plus 200mg aspirin/kg BW per d. Neither aspirin nor niacin was effective in lowering body temperatures vs HEC. Heifers fed HEA had maximum body temperatures that were higher (P<0.01) than both the HEC and LE groups. Heifers fed HEN had body temperatures that were higher (P<0.01) than those of LE-treated heifers but not different (P>0.10) than HEC heifers. Heifers fed LE had higher (P<0.01) serum prolactin concentrations than HEA and HEC heifers, but not HEN heifers (P>0.10). Dietary inclusion of aspirin had no beneficial effect on body temperature and prolactin levels in heifers fed high-endophyte fescue forage, whereas inclusion of niacin tended to increase serum prolactin levels.