Author
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Aiken, Glen |
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Submitted to: Progressive Cattlemen
Publication Type: Popular Publication Publication Acceptance Date: 3/10/2016 Publication Date: 3/24/2016 Citation: Aiken, G.E. 2016. Feeding soyhulls on toxic tall fescue is option for stockers. Progressive Cattlemen. Pgs. 1-5. Interpretive Summary: Tall fescue is a cool-season grass that is well adapted to the soils and climate in the transition zone between the temperate northeast and the subtropical southeast. A fungal endophyte that infects most plants of tall fescue produces alkaloids that imparts tolerances to grazing, dry soils, and low fertility; unfortunately, it also produces ergot alkaloids that causes a toxicosis in cattle. Signs of toxicosis are poor performance (reduced calving percentages, low weaning weights, and poor post-weaning weight gain) and thriftiness. Cattle also can suffer severe heat stress in moderate air temperatures, maintain their rough hair coats in the summer and have low prolactin hormone concentrations. Cattle production on tall fescue is primarily cow-calf because post-weaning weight gain performance is typically too low for profitable production of stockers. Results of a grazing experiment demonstrated that combining the feeding of soybean hulls with ear implantation of estradiol can substantially improve steer average daily weight gain, and daily feeding of soybean hulls at approximately 0.8 percent of body weight can mitigate fescue toxicosis. Follow-up research indicated that isoflavones, which are phytoestrogens concentrated in soybean hulls, are combined with estradiol in the implant to cause the enhancement of weight gain efficiency and mitigation of fescue toxicosis. Isoflavones could offer a natural product that promotes growth and well-being of cattle grazed on toxic endophyte-infected tall fescue. However, much more research is needed to determine the potential benefits of isoflavones. Technical Abstract: Poor weight gain and thriftiness of wean beef calves on toxic endophyte-infected tall fescue has resulted in most the 15 million hectares of tall fescue in the USA to be utilized for cow-calf and not stocker production. An article was written that discusses results of a grazing experiment with toxic endophyte-infected tall fescue that demonstrated how soybean hulls, fed to provide a daily consumption at approximately 0.8 percent body weight, can be combined with ear implantation with estradiol to enhance daily weight gain and mitigate fescue toxicosis. The study evaluated four treatments: 1) pasture-only control, 2) ear implants only, 3) feeding soybean hulls only, and 4) combining implants and feeding soybean hulls. There was a synergistic effect of combining the two treatments on average daily weight gain. Steers fed soybean hulls also exhibited less severe signs of toxicosis. Follow-up research indicated that the enhanced steer performance and mitigation of fescue toxicosis was associated with the combined estrogenic activity of phytoestrogen isoflavones in soybean hulls and the estradiol from the ear implants. Further research is needed to verify this, but this management approach appears to have potential as an option for producing stockers on toxic endophyte-infected tall fescue. |
