Effects of four mono- and sesquiterpenes on the consumption of alfalfa pellets by sheep

Effects of individual terpenes on alfalfa pellet intake by lambs were examined in four experiments. Forty-five lambs (nine 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, 0.5, 1, 2, and 10x) were multiples of the concentration (x) of a specific terpene in tarbush. Terpenes were applied to alfalfa pellets (0.64 kg x lamb(-1) x d(-1), DM basis), and consumption was 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), whereas myrcene and beta-pinene exerted no effect on the consumption of alfalfa pellets by lambs. Camphene and caryophyllene oxide may be involved in the differential herbivory of individual tarbush plants by livestock.