Submitted to: Cow Country News
Publication Type: Popular Publication
Publication Acceptance Date: 2/11/2017
Publication Date: N/A
Interpretive Summary: Tall fescue during the spring can produce an ample supply of lush vegetative growth, but it also accumulates toxic ergot alkaloids that causes fescue toxicosis, a malady that adversely affects cattle performance and well-being. Ergot alkaloids can become extremely high in the seed heads (2 to 8 parts per million compared to 0.1 to 1.0 for leaf blade tissues) and, unfortunately, the cattle readily graze the toxic seed heads that can give them a heavy dose of alkaloids. There are options in alleviating or mitigating fescue toxicosis in the late spring and summer? Removal of the seed heads by either mowing or spraying with metsulfuran-methyl that suppresses emergence of fescue seedheads are options in alleviating seeds as a source of ergot alkaloids. Soy hulls fed daily to provide a daily consumption of 0.75 to 1.0 percent of body weight is another option in mitigating fescue toxicosis. Overseeding toxic endophyte-infected tall fescue with red clover can dilute ergot alkaloids in the diet, and also contains phytoestrogen isoflavones that have shown to mitigate fescue toxicosis. Incidence of fescue toxicosis can be alleviated if pastures of toxic endophyte-infected tall fescue are replanted with novel, non-toxic endophyte-infected tall fescue. This information should be helpful to cattle producers that manage toxic endophyte-infected tall fescue and are interested in management options to alleviate or mitigate fescue toxicosis. Producers are advised to consult with their extension agents to assess the advantages and disadvantages of each option and determine the best option for their farms.
Technical Abstract: An article was written that discussed options in alleviating or mitigating fescue toxicosis in the spring and summer. Seedheads of tall fescue are highly concentrated with toxic ergot alkaloids and the cattle selectively graze immature seedheads of tall fescue. Removal of the seedheads is an approach to alleviate the toxic seedheads as a source of highly concentrated alkaloids. The seedheads can either be mowed or sprayed with metsulfuran-methyl that suppresses emergence of fescue seedheads. Feeding soy hulls to provide a daily consumption of 0.75 to 1.0 percent of body weight is another option in mitigating the adverse effects of ergot alkaloids on cattle performance and well-being. There is a benefit of overseeding toxic endophyte-infected tall fescue with red clover. The red clover can dilute the ergot alkaloids in the diet, but it also contains phytoestrogen isoflavones, which has indication of relaxing the persistent vasoconstriction caused by ergot alkaloids. To alleviate incidence of fescue toxicosis, pastures of toxic endophyte-infected tall fescue can be replanted with novel, non-toxic endophyte-infected tall fescue. The article discusses the advantages and disadvantages of each of these options in reducing the adverse effects of ergot alkaloids on cattle performance and well-being.