Watch for pine-needle abortions

Gary Sliworsky
Ag. Rep.

Here is something that I wasn’t aware of until I saw an article by David P. Price, a consulting nutritionist, in Cattlemen pine-needle abortion.
Apparently it is something that catches many cow-calf operators off guard every year. The reason is that when it happens, it happens fast. Unlike other toxic plants which take chronic exposure over a long period of time, pine needle abortion only takes about 1.5 pounds of pine-needles over a few days to cause massive numbers of abortions. The abortions can occur immediately, or can play out over a couple of weeks.
The actual compound in pine needles that causes the abortions has not been discovered, but it is known that it has an estrogenic effect on the cow. Therefore, pine-needles can also interfere with conception and otherwise detrimentally affect reproduction performance whenever they are consumed. Cows suffering pine needle abortion also typically have reduced conception rates following the abortion. Abortion is the usual symptom since winter is when most pine needle consumption occurs.
Cattle ordinarily do not consume pine needles. The usual scenario involves storms and snow cover. The most common situation is when cattle are being wintered on hay. If a severe storm prevents the feeding of hay for several days, cows will consume pine needles if nothing else is available.
It is important to realize that pine bark and branch buds are even more toxic than the needles. As a practical matter, this becomes of concern if cattle are around logging operation, saw mills, etc.
Diagnosing pine-needle abortion is usually a simple matter of deduction. Cows have access to nothing but pine needles and/or you can see where cattle were browsing on pine branches and buds. In the case of cows that have died trying to abort, pine needles can obviously be found in the rumen. A more sophisticated analysis of the rumen would show a drastically diminished bacterial population, as pine needles are toxic to bacteria.
Since the abortion is caused by hormonal effects on the cow, the fetus sill appear quite normal.
Prevention of pine needle abortion is difficult as it centers around the weather. Hay or other feed reserves can become academic if severe storms prevent distributing the feed.