@proceedings {JRN53998, title = {Relationship between one-seed juniper terpene concentration and herbivory by small ruminants}, volume = {91}, year = {2013}, month = {07/2013}, pages = {553}, publisher = {Journal of Animal Science}, address = {Indianapolis, IN}, abstract = {

Plant secondary metabolite affect the amount of use by herbivores for serveral woody species.\  We examined the relationship between terpenoid concentrations and Juniperus monosperma herbivory by small ruminants.\  The study was part of a larger effort in which goats (n = 10) or mixed species (5 goats and 4 sheep) were allotted to 16 plots (20 \× 30 m) containing one-seed juniper for 6 d during 2 seasons at 2 stocking rates. Juniper leaves were sampled from 311 saplings on the same day they were browsed. Saplings were categorized by size (small [\<0.5 m], medium [0.5-1.0 m] or tall [\>1.0 m]) and browsing intensity (low [\<33\%], moderate [33-66\%] or heavy [\>66\%] herbivory). Juniper bark was also collected from 12 saplings during spring. Leaves and bark were analyzed for terpenoids with gas chromatography-mass spectrometry. Terpene data were pooled across species and stocking rate and ANOVA was conducted for season, sapling size, and herbivory level. The volatile profile of one-seed juniper leaves and bark consisted of 65 and 55 compounds, respectively. Total estimated terpenoid concentrations in leaves and bark were 18.3 \± 0.3 and 8.9 \± 0.8 mg/g, respectively, and the dominant terpene in both tissues was \α-pinene (11.1 \± 0.2 and 7.6 \± 0.7 mg/g, respectively). Total terpenoid concentration was greater (P \< 0.001) in spring than summer (20.6 \± 0.5 vs. 16.7 \± 0.3 mg/g, respectively) and lower (P \< 0.001) in small saplings than medium or tall saplings (16.5 \± 0.6 vs. 19.8 \± 0.4 and 19.5 \± 0.4 mg/g, respectively). Total concentration also differed (P \< 0.001) among all 3 browsing categories (16.1 \± 0.4, 18.7 \± 0.5, and 21.2 \± 0.6 mg/g for heavy, moderate, and light herbivory, respectively). Approximately 42\% of the variation in browsing intensity could be explained (P \< 0.001) by 12 compounds ([E]-\β-farnesene, cis-sabinene hydrate, bornyl acetate, \γ-eudesmol, germacrene A, \γ-cadinene, \α-pinene, [Z]-\β-ocimene, terpin-4-ol, cispiperitol, cis-p-menth-2-en-1-ol, and camphene hydrate). Our results indicate that the terpene profile of one-seed juniper is related to sapling size, season, and degree of use by sheep and goats.

}, keywords = {goat, sheep, terpene}, author = {Richard E. Estell and S. A. Utsumi and Andr{\'e}s F. Cibils and D.M. Anderson} } @conference {50511, title = {Sheep and goat grazing as a tool to mange encroachment of one-seed juniper (Juniperus monosperma Engelm. Sarg.)}, booktitle = {III Simposium Internacional de Pastizales}, year = {2006}, month = {August 9-11, 200}, pages = {13}, address = {Chihuahua, Mexico}, abstract = {The efficacy of using prescribed grazing by sheep and goats to suppress one-seed juniper re-invasion could be improved by providing adequate nutrients to help animals detoxify plant terpenes. We analyzed the terpenoid chemistry of one-seed juniper leaves and conducted feeding trials with 12 Ramboullet ewes and 12 Boer-Spanish nannies to determine if juniper intake (JI) varied seasonally (summer, fall or winter) or was affected by the amount and kind of crude protein (CP) available to detoxify terpenes. Diets were a sudangrass (Sorghum sudanensis) hay with either no protein added (Control diet: 5\% CP), or with soybean meal (degradable CP: DCP; 12.5\% CP) or fishmeal (by-pass CP: BPCP; 12.5\% CP). Juniper trials were conducted for 10 days in each season and consisted of a 30 min feeding bout on juniper branches (175g) attached to wooden stands (0.8 m height). Juniper leaves contained 51 terpenoids, 14 represented 95 \% of the total terpenoid amount, and {\'a}-pinene was the most abundant terpene (65\%). Juniper intake was greater for goats (0.54g kgBW-1) than Sheep (0.23g kgBW-1), and was higher for animals receiving the DCP (0.5g kgBW-1) and BPCP (0.41g kgBW-1) supplements than for control animals (0.25g kgBW-1). JI also varied among seasons (winter: 0.54g kgBW-1; summer: 0.38g kgBW-1; fall: 0.23g kgBW-1). Sheep and, especially, goats could be used in prescribed grazing programs to suppress juniper re-invasion. Greater suppression could be expected from goats browsing during winter, provided that protein levels are sufficient to allow them to detoxify terpenes efficiently.}, keywords = {goat, sheep, uniper}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro} }