January 5, 2003                                                                                     Ralph Phillips, Farm Advisor

                                                                                             Range/Natural Resources and Livestock

Several months ago a rancher contacted me about the possibility of having pine needle abortion problems in his herd.  I was not aware of any problem in the county so I contacted the poisonous plant research laboratory, USDA, Logan, Utah.  The people at the lab said that there was a possibility that junipers could be causing the problem.  They said that we should identify the type of juniper and send them samples to be analyzed for the compound in pine and juniper that can cause abortion.  We have identified the type of juniper and had it analyzed.

Before we talk about the analysis it would be appropriate to discuss the history of pine needle abortion and how the toxin compound caused abortion.  It was first reported in the 1920s that pine needles could be the cause of abortion in cattle.  By 1952 research had proved that Ponderosa or yellow pine could cause abortion.  It was in the mid 1990s that the abortion causing compound was isolated and identified, isocupressic acid (ICA).  Further research showed that ICA caused late term (last trimester) abortion.  The toxicity of ICA is dose dependent and large doses of the compound could cause the cow to abort sooner than low doses.  So, it is difficult to say exactly how many pounds of pine or juniper a cow needs to eat before she aborts.  In some cases cows will need to eat 10 - 15 pounds a day for several days before they will abort, but as little as 4 or 5 pounds can cause cows to abort.

ICA restricts the blood flow to the placenta and the calf basically starves to death in the cow's uterus.  Smaller amounts of ICA will take longer for the calf to starve to death and larger amounts will starve the calf to death in a very short time.  Also, the larger the calf, the quicker ICA can cause abortion.  Larger calves require more nutrients from the cow, thus taking a shorter time to die.  One of the signs of ICA abortion is a large percent of the cows that abort late term will have a retained placenta.

Kern County is known to have three species that have caused abortion; Ponderosa pine, Jeffery pine and California juniper.  All of these species have high levels of ICA.  Before becoming too concerned, remember that cows must eat the needles during the last trimester of pregnancy and there also must be an ample supply of trees to graze and the cow must get enough pine needles to cause abortion.  Just because these types of trees are on your range does not mean ICA is the problem.  However, if you have unexplained abortions, ICA could be the cause.