|Estell, Richard - Rick|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2006
Publication Date: 8/9/2006
Citation: Utsumi, S.A., Cibils, A.F., Estell, R.E., Soto-Navarro, S. 2006. Sheep and goat grazing as a tool to manage encroachment of one-seed juniper (Juniperus monosperma Englem. Sara.) [abstract]. III Simposium Internacional de Pastizales. Conservacion y Sustentable de Pastizales. August 9-11, 2006, Chihuahua, Mexico. p. 13.
Technical 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 '-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.