Submitted to: Cattleman's Magazine
Publication Type: Popular Publication
Publication Acceptance Date: 3/12/2009
Publication Date: N/A
Technical Abstract: Knowledge of the detrimental effects of toxic tall fescue on bull reproductive performance is minimal. In natural breeding, reduced bull performance could decrease the pregnancy rate of the cowherd. Scientists from ARS in Booneville, AR, and the University of Arkansas investigated the influence of fescue type on sperm characteristics in bulls. Bulls grazed either toxic or nontoxic fescue, and semen and scrotal circumference were measured monthly. Semen from bulls grazing toxic fescue had reduced motility and morphology compared with bulls grazing nontoxic fescue pastures. Beef producers should take into consideration the cow-to-bull ratio when bulls are grazing toxic fescue especially during the hotter months of the summer. Over-use of a bull maintained on toxic fescue could exacerbate the reduced fertility, resulting in more cows being open at the end of the breeding season. Use of novel fescue varieties or other non-toxic supplementation strategies before and during the breeding season will alleviate the detrimental effects of toxic fescue on bull performance. This information is important to livestock producers and extension personnel.