Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/3/2002
Publication Date: 12/1/2002
Citation: ESTELL, R.E., FREDRICKSON, E.L., ANDERSON, D.M., HAVSTAD, K.M., REMMENGA, M.D. EFFECTS OF FOUR MONO- AND SESQUITERPENES ON CONSUMPTION OF ALFALFA PELLETS BY SHEEP. JOURNAL OF ANIMAL SCIENCE. 2002. V. 80(12). P. 3301-3306. Interpretive Summary: The encroachment of shrubs into arid grasslands is a serious problem. These shrubs often contain chemicals causing them to be unpalatable for livestock and wildlife. We are studying the role of plant chemicals in regulating shrub consumption by livestock. Our early work showed livestock preference for tarbush varied greatly from plant to plant and chemicals on the leaf surface were partly responsible for the variability. Volatile chemicals that were related to tarbush consumption in previous studies were applied to alfalfa pellets and fed to lambs to determine if these terpenes controlled intake when applied individually. Two of the four compounds tested (camphene and caryophyllene oxide) reduced intake while myrcene and Beta-pinene did not affect intake. Camphene and caryophyllene oxide may be involved in the avoidance of shrubs by livestock. This information may ultimately help us find ways to alter the amount of a particular plant species eaten by livestock.
Technical Abstract: Effects of individual terpenes on alfalfa pellet intake by lambs were examined in four experiments. Forty-five lambs (9 lambs/treatment) were individually fed alfalfa pellets sprayed with either camphene, myrcene, caryophyllene oxide, or beta-pinene at one of five concentrations (one terpene per experiment). Treatments (0, .5, 1, 2, and 10X) were multiples of the concentration (X) of a specific terpene in tarbush. Terpenes were applied to alfalfa pellets (.64 kg.lamb-1.d-1, DM basis) and consumption wa measured during a 20-min interval for 5 d. Lambs were maintained and fed alfalfa pellets in one group (except during 20-min tests) at a mean total daily intake of 4.7% of BW (DM basis). Camphene and caryophyllene oxide tended to decrease intake (linear contrasts were P = .0651 and P = .0504, respectively), while myrcene and beta-pinene exerted no effect on consumption of alfalfa pellets by lambs during the 20-min interval. Camphene and caryophyllene oxide may be involved in the differential herbivory of individual tarbush plants by livestock.