Author
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Short, Robert |
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Submitted to: Montana Farmer
Publication Type: Popular Publication Publication Acceptance Date: 7/1/1999 Publication Date: N/A Citation: N/A Interpretive Summary: n/a Technical Abstract: The effects of pine needles on inducing abortions in cattle are documented to be primarily a problem in late pregnant cows and are manifested by a decrease in blood flow to the uterus, stress to the calf and premature parturition. Assays for the biological activity have been developed using pregnant guinea pigs and a late pregnant placentome perfusion system. Several species of wild ungulates (bison are an exception) do not respond to the effects of pine needles probably because of differences in ruminal metabolism, but attempts to transfer ruminal microbes from other species to cattle have not been successful in preventing pine needle effects. Two classes of chemical compounds have been identified as potential culprits in the effects of pine needles, but we do not know for sure how or if each one is actually involved. Attempts to counteract the effects of pine needles have not been successful, and only feeding corn silage has prevented consumption of pine needles. Of those species tested, needles from Ponderosa pine are the only ones that have been shown to induce the problem. Effects of phytoestrogens in sheep and dairy cattle are well documented with the effects in sheep being much more severe. Management alternatives that include appropriate pasture management, selection of low estrogen varieties and feed monitoring are available to prevent these effects. When managing beef cattle in feedlots and during the breeding season, be aware of symptoms and potential sources of estrogen - any legume pasture, hay or haylage; moldy hay or grain; or any estrogenic products that the animals may be receiving. |
