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United States Department of Agriculture

Agricultural Research Service

Title: The Effect of Polyethylene Glycol on Intake of Mediterranean Shrubs by Sheep and Goats

Authors
item Rogosic, Jozo -
item Pfister, James
item Provenza, Frederick - UTAH STATE UNIVERSITY
item Pavlicevic, J -

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2008
Publication Date: October 2, 2008
Repository URL: http://www.pprl.ars.usda.gov
Citation: Rogosic, J., Pfister, J.A., Provenza, F.D., Pavlicevic, J. 2008. The Effect of Polyethylene Glycol on Intake of Mediterranean Shrubs by Sheep and Goats. Journal of Animal Science 86:3491-3496. doi:10.2527/jas.2007-0828.

Interpretive Summary: Rangelands in Croatia and throughout the Mediterranean basin are dominated by shrubs. Low nutritional quality and high levels of secondary compounds can result in low consumption of Mediterranean shrubs by goats and sheep. In 4 trials, we examined the effect of polyethylene glycol (PEG) and number of plant species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats (6 PEG vs. 6 controls). In trial 1 (6 shrubs), goats ate more daily total shrub biomass than did sheep (60.7 vs. 45.9 ± 2.6 g/kg body weight [bw], respectively). PEG-supplemented animals consumed more total shrubs than controls (56.7 vs. 50.0 ± 2.6 g/kg bw). In trial 2 (3 shrubs), both species of animals showed a numerical decrease in total shrub intake. Sheep receiving PEG ate more total shrubs than did controls, but no PEG effect was found for goats. In trial 3 (2 shrubs), PEG had a positive effect on total shrub intake for both sheep and goats when offered Arbutus and Pistacia spp.. In trial 4 (1 shrub), PEG had a positive effect on intake of Pistacia lentiscus. PEG-supplemented goats ate more Pistacia (39.6 g/kg) than did PEG-supplemented sheep (28.1 g/kg), whereas control sheep and goats ate similar amounts (12.2 and 15.3 g/kg, respectively). As the number of shrubs in the diet decreased, the impact of PEG on shrub intake increased. PEG alone had a greater influence on sheep than on goats, and it had the most influence on both sheep and goats when only one or two foods were available.

Technical Abstract: Low nutritional quality and high levels of secondary compounds can result in low consumption of Mediterranean shrubs by herbivores. In 4 trials, we examined the effect of polyethylene glycol (PEG) and number of species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats (6 PEG vs. 6 controls). In trial 1 (6 shrubs), goats ate more daily total shrub biomass than did sheep (60.7 vs. 45.9 ± 2.6 g/kg body weight [bw], respectively). There was a trend (P=0.08) towards a positive PEG effect on total shrub intake, with PEG-supplemented animals consuming more total shrubs than controls (56.7 vs. 50.0 ± 2.6 g/kg bw). In trial 2 (3 shrubs), both species of animals showed a numerical decrease in total shrub intake. Sheep receiving PEG ate more (P = 0.002) total shrubs than did controls, but no treatment effect was found for goats. In trial 3 (2 shrubs), PEG had a positive effect (P < 0.001) on total shrub intake for both sheep and goats when offered Arbutus and Pistacia spp.. In trial 4 (1 shrub), PEG had a positive effect (P < 0.001) on intake of Pistacia lentiscus. PEG-supplemented goats ate more (P < 0.05) Pistacia (39.6 g/kg) than did PEG-supplemented sheep (28.1 g/kg), whereas control sheep and goats ate similar amounts (12.2 and 15.3 g/kg, respectively). Our findings suggest that plant biochemical diversity plays an important role in herbivore diet selection, enabling animals to better meet their nutritional needs and avoid toxicity. Further, as the number of shrubs in the diet decreased, the impact of PEG on shrub intake increased. PEG alone had a greater influence on sheep than on goats, and it had the most influence on both sheep and goats when only one or two foods were available.

Last Modified: 7/24/2014
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