The effect of western juniper on the estrous cycle in beef cattle

Authors: Welch, Kevin; Stonecipher, Clinton - Clint; Gardner, Dale; Panter, Kip; PARSONS, CORY - Oregon State University; DEBOODT, TIM - Oregon State University; JOHNSON, BRYAN - Volunteer

Submitted to: Research in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2014
Publication Date: 2/1/2015
Publication URL: http://handle.nal.usda.gov/10113/62771
Citation: Welch, K.D., Stonecipher, C.A., Gardner, D.R., Panter, K.E., Parsons, C., Deboodt, T., Johnson, B. 2015. The effect of western juniper on the estrous cycle in beef cattle. Research in Veterinary Science. 98:16-18.

Interpretive Summary: Numerous evergreen trees and shrubs contain labdane acids, including isocupressic acid, which can cause late-term abortions in cattle. Recent research has shown that the bark from western juniper trees (Juniperus occidentalis) can also cause late-term abortions in cattle. Analysis of the bark, needles, and berries from western juniper trees determined that all contain labdane acids similar to those found in ponderosa pine needles, albeit in lower concentrations. Several livestock producers in Oregon have also reported irregular estrous cycles and lower reproductive rates in cattle that utilize juniper-infested summer rangelands. There are numerous plants that are known to adversely affect the estrous cycle of cattle including several phytoestrogen containing plants (soybeans and clovers) and locoweeds. Consequently, exposure to these plants during the breeding season could effectively prevent the cattle from becoming pregnant, delaying pregnancy, or resulting in an inability to maintain pregnancy. Therefore, the objective of this study was to determine if consumption of western juniper alters the estrous cycle of beef cows and therefore could extend the calving interval or reduce conception rates. The data presented in this study indicate that exposure of cattle to western juniper, at the dose administered in this study, will not adversely affect estrus or the estrous cycle in cattle, their ability to become pregnant, or their ability to maintain pregnancy during the first trimester. However, cattle producers should still be cognizant of the potential of western juniper trees to cause late-term abortions in cattle.

Technical Abstract: Numerous evergreen trees and shrubs contain labdane acids, including isocupressic acid, which can cause late-term abortions in cattle. Recent research has shown that the bark from western juniper trees can also cause late-term abortions in cattle. Additionally, ranchers have observed that cattle in western juniper-infested rangelands tend to have decreased conception rates. The objective of this study was to determine if western juniper alters the estrous cycle of cattle. Fourteen heifers (10 treated and 4 control) were monitored for 74 days for signs of normal estrous behavior, with a 21 day feeding trial with western juniper bark from days 28-48, after which the cattle were bred naturally with a bull. The cattle were checked for pregnancy 30 days after all cattle had been bred. The data from this study indicate that exposure to western juniper bark does not affect normal estrus, estrous cycle or conception rates of cattle.