Elk Study May Help Cattle

Elk have yielded a secret that could help rangeland cattle bear healthy calves even if they eat Ponderosa pine needles during their pregnancies.

Scientists with the Agricultural Research Service in Montana are the first to discover that pregnant elk who eat the needles show no reproductive problems or constriction in their blood vessels. University of Iowa and Iowa State University researchers collaborated in the study.

Scientists as well as ranchers have long known that problems arise for pregnant cattle that eat the needles in the last trimester. Blood flow to the uterus decreases dramatically. The cow delivers early, and her calves often die. But elk apparently can neutralize the natural toxins in the needles.

Ponderosa pines, common on Western grazing lands, cover 27 million acres in the United States. In 1988, the last available estimate, so-called “pine needle abortions” cost cattle ranchers more than $20 million annually.

At ARS’ Fort Keogh Livestock and Range Research Laboratory, Miles City, Mont., scientists are testing several ruminants--including bison, sheep, goats and other grazers--to find ways to prevent abortions in cattle caused by pine needle poisoning. Ruminants are mammals whose stomachs have four compartments, the first one being the rumen.

The scientists believe natural microorganisms in the elk rumen render the needles harmless. Researchers are working to determine the differences between elk and cow rumen flora, with the goal of reducing or eliminating the toxic effects of pine needles. They also are evaluating bighorn sheep and white-tailed deer.

In related work, the university-ARS team unexpectedly discovered--and patented--potentially useful chemicals called waxy lipids in the pine needles. These lipids appear to have no effects on pregnant cattle other than restricting uterine blood flow. That might make them beneficial for treating postpartum hemorrhages and other human ailments.

Scientific contact: Robert Short, USDA-ARS Fort Keogh Livestock and Range Research Laboratory, Miles City, Mont., phone (406) 232-4970, fax 232-8209, bshort@larrl.ars.usda.gov.