17 P. Rodriguez-Santillan H. Bernal-Barragan Ma. Cerrillo-Soto H. Gonzalez-Rodriguez A.S. Juarez-Reyes Guerrero-Cervantes R.G. Ramirez-Lozano Journal of Animal and Plant Sciences JAPS 20142014/12/01 24 6 1629-1635 1018-7081 NA <p>Leaf litter samples from two undisturbed sites in the Tamaulipan Thornscrub vegetation at northeastern Mexico were evaluated monthly, during 2007, for chemical composition, true&nbsp;<em>in vitro</em>&nbsp;organic matter digestibility (IVOMD),&nbsp;<em>in vitro&nbsp;</em>gas production (IVGP, 24 h), metabolizable energy (ME) and microbial protein (MP), in absence or presence of polyethylene glycol (PEG). Neutral detergent fiber (organic matter; mean = 40.8%), acid detergent fiber (ADFom; 28.8%), lignin (20.2%), crude protein (CP; 11.5%), condensed tannins (CT; 0.6%), ether extract (EE; 2.9%) contents, and IVOMD (63.0%) values and the interactions site*month were different between sites and among months. Gas production without (53.2 ml/200mg) and with PEG (59.1), ME (9.9 and 10.9 MJ/kg, respectively) and MP values (11.5 and 13.8, &micro;mol, respectively) were not different between sites, but were different among months. When leaf litter deposition was high (dry months; January-June) in both sites, NDF, lignin and CP were also higher than in other months. The&nbsp;<em>in vitro</em> gas production, ME and MP were higher with the addition of PEG compared with the samples without PEG. Moreover, MP content was higher during the wet months (July-September). Based on chemical composition and fermentation values, litter fall leaves have a high potential to be used as feed resource for range small ruminants.</p> Chemical Composition; In Vitro Gas Production Parameters; Litter Fallen Leaves; Polyethylene Glycol; Tamaulipan Thornscrub Vegetation Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2014-JAPS-233