Submitted to: Professional Animal Scientist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/11/1997
Publication Date: N/A
Citation: Interpretive Summary: Endophyte-infested tall fescue is easily established, widely adapted, and persistent under poor management. These attributes have resulted in it being the most widely grown perennial grass in the eastern USA. A major problem, however, is that cattle grazing tall fescue developed symptoms of toxicosis, which substantially reduces cattle reproductive and growth performance. The toxicosis is caused by the comsumption of endotoxins produced by the endophyte. Because of the toxicosis, very little tall fescue is utilized for backgrounding cattle for the feedlot. Replanting infested stands with noninfested seed is one way of alleviating the toxicosis, but noninfested tall fescue has shown to not tolerate environmental stresses. One possible option could be to feed the cattle in amounts that will dilute the endotoxins in the diet and boost animal gains. A grazing study was conducted to compare steer performance between endophyte-infested and noninfested tall fescue with treatments of either free-choice feeding of broiler litter-corn or pasture only. Average daily gain and total liveweight gain per acre were increased by feeding the litter-corn on infested pastures, but not on those that were noninfested. Although the steers fed litter-corn on infested pastures showed some symptoms of toxicosis, the symptoms were not as pronounced as those not fed the litter-corn. Feed cost for the increase in daily weight gains on infested tall fescue was less than 45 cents if corn cost is less than 150 dollars/metric ton. Feeding litter-corn free-choice to growing cattle on infested tall fescue can reduce the severity of toxicosis and enhance average daily gain and total liveweight gain acre.
Technical Abstract: Poor weight gain of cattle grazing endophyte-infested tall fescue (Festuca arundinacea Schreb.) and poor persistence of grazed endophyte-free tall fescue have limited their use in stocker production systems. A grazing study was conducted to determine if feeding broiler litter and corn (Zea mays L.) can provide cost-effective enhancement of steer performance on infested and noninfested tall fescue. Treatments of either free-choice feeding of broiler litter-corn (1:1; as fed) or pasture-only were imposed on steers grazing infested and noninfested stands of 'Kentucky-31' tall fescue. Feeding broiler litter-corn increased (P<0.001) average daily gain (ADG) and gain per acre for infested, but not (P>0.10) noninfested tall fescue. Furthermore, ADG and gain per acre for the broiler litter-corn treatment on infested pastures were similar to those observed for noninfested pastures. Steers fed broiler litter-corn on infested tall fescue had reduced serum prolactin (P<0.01) relative to those on noninfested tall fescue. Approximately 70% of the steers fed broiler litter-corn on infested tall fescue had rough or transitional haircoat ratings, whereas 85% of the steers on the pasture-only treatment for noninfested tall fescue had sleek haircoats. Cost of corn per incremental increase in ADG was cost effective for most cattle markets if cost per ton was less than 150 dollars. Free-choice feeding of broiler litter-corn to steers on infested tall fescue can reduce the severity of fescue toxicosis and enhance weight gains.