The Black Hills of eastern Wyoming and western South Dakota have a history of serious abortion problems in cattle related to ponderosa pine (Pinus ponderosa). Abortion caused by ingestion of ponderosa pine needles is known to be a major economic problem in the Western U.S. and Western Canada, with losses as high as 50 percent in some herds.
Pregnant cattle who consume ponderosa needles and buds are at risk of abortion and premature birth of calves. Weak calves and retained fetal membranes are often associated with these abortions.
The stage of gestation when pine needles are consumed influences the risk of aborting. Cattle in late gestation (third trimester) have been found to be more severely impacted. Additionally, cattle consuming pine needles at 250 days of gestation or later are at risk of calving weak calves who need immediate attention to survive.
Cattle tend to eat more pine needles during cold weather when grazing in ponderosa-forested areas. Higher snow depth, reduced amounts of grazable forage and cold ambient temperatures are contributing factors in grazing cattle’s consumption of ponderosa pine needles. Therefore, as cattle enter late gestation and we continue to experience cold temperatures, it is important for producers to take measures to prevent consumption of pine needles.
High-protein diets may increase the risk of these losses. Also, note that losses cannot be decreased by straw, mineral, salt or bentonite (chemical binder) supplementation. Therefore, the best prevention method is to avoid exposure to any source of pine needles, whether they are fresh, dry or on fallen trees.
This is a challenge for producers, as fencing ponderosa pine areas off is not economically feasible and is time consuming. However, it is important to understand the issue and manage it to avoid economic loss. One solution may be fencing some areas off only to mitigate the risk. Another solution is to plan ahead and avoid grazing these areas when possible. However, this practice may not be feasible for all producers. — Alex Orozco, UW Extension educator
