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This Article Full Text (PDF) All Versions of this Article: jas.2007-0828v1 86/12/3491    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rogosic, J. Articles by Pavlicevic, J. Search for Related Content PubMed PubMed Citation Articles by Rogosic, J. Articles by Pavlicevic, J.

The effect of polyethylene glycol on intake of Mediterranean shrubs by sheep and goats

¹ Department of Ecology, Agronomy and Aquaculture, University of Zadar, Mihovila Pavlinovica bb, 23000 Zadar, Croatia , ² Poisonous Plant Research Laboratory, ARS, USDA, Logan, UT 84341 , ³ Department of Forestry, Range, and Wildlife Sciences, Utah State University, Logan UT 84322-5230 ⁴ Department of Animal Nutrition, Faculty of Agronomy, University of Mostar, Biskupa Cule 10, 88000 Mostar, Bosnia and Herzegovin

jrogosic{at}unizd.hr

Abstract

Low nutritional quality and high levels of secondary compounds can reduce consumption of Mediterranean shrubs by herbivores. In 2 sequential trials, we examined the effect of polyethylene glycol (PEG) and number of shrub species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats. The PEG (25 g) was fed to experimental animals with barley. In trial 1 (6 shrubs), goats ate more (P = 0.0008) daily total shrub biomass than did sheep (60.7 vs. 45.9 ± 2.6 g/kg BW). 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). Trial 2 (using 3 shrubs) was a continuation of Trial 1, except that animals were given less barley and treatment animals were given more PEG (50 g). Both sheep and goats showed a numerical decrease in total shrub intake from Trial 1 to Trial 2. Sheep receiving PEG ate more (P = 0.002) total shrubs than did controls, but no PEG effect was found for goats. Thus, PEG had a greater influence on sheep than goats when only 3 shrubs were offered, a result that may be related to the fact that fewer shrubs with complementary secondary compounds were offered, and that goats appear to have a greater ability to consume and detoxify secondary compounds from Mediterranean shrubs. Overall, as the number and diversity of shrubs offered increased, supplemental PEG had less effect on increasing intake for both goats and sheep.

Key Words: Chaparral • Diet selection • Maquis • Shrubland • Secondary compounds • Tannins