Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Popular Publication
Publication Acceptance Date: 10/1/2002
Publication Date: 1/15/2003
Citation: SHORT, R.E., GRINGS, E.E., MACNEIL, M.D. A MODEL FOR DETERMINING RISK OF PINE NEEDLE ABORTION IN CATTLE CALVING AT DIFFERENT TIMES OF THE YEAR. RESEARCH UPDATE FOR FORT KEOGH LIVESTOCK AND RANGE RESEARCH LABORATORY. p. 52-53. 2003. Interpretive Summary: Consumption of needles from Ponderosa pine trees (Pinus ponderosa) cause cattle to abort. Loses due to pine needle abortions are a multimillion dollar problem for cattle producers in the Western United States. In order to decrease these loses, producers need to be able to manage risk which is determined by the risk of consumption and the risk of an abortion once pine needles are consumed. The risk of consumption is primarily related to cold weather and storms. The risk of an abortion after consumption of pine needles is determined by the amount of needles consumed and stage of pregnancy. We found that pine needle-induced abortions did not occur during the first half of pregnancy, but the effect increased markedly during the second half of pregnancy with most cows aborting when pine needles were consumed after 250 days of pregnancy. In order to objectively assess the potential role of calving date in pine needle abortion risk, a model was developed to combine the risk of consumption of pine needles and the risk of an effect once needles are consumed. That model was then used to assess the role of calving date in pine needle abortion risk.
Technical Abstract: Cow-calf producers in areas with Ponderosa pine trees are at risk of production loses due to pine needle induced abortions. The level of risk is determined by a combination of the risk of cows eating pine needles and the risk of an effect once pine needles are eaten. Little can be done to alter the risk of an effect once needles are eaten, but producers can minimize risk of consumption by changing season of calving. Calving in summer or fall will have little risk of pine needle abortion. For producers in areas with similar cold temperature profiles as at Miles City, MT, risk of abortions is highest for cows calving from January 15 through May 1. Locations with a lower risk of cold temperature will have a lower risk of abortions and a shorter time period where calving season has a high risk.