The effect of Saccharomyces cerevisiae as live cells (LC) or cells extract (CE) on in vitro gas production (GP) kinetics and ruminal fermentation parameters of a total mixed ration (TMR) consisting of commercial concentrate and alfalfa hay [1:1 dry matter (DM)] as a substrate was studied. The TMR was incubated with CE at 1, 2 and 4 mg/g or LC at 0.3, 0.6 and 0.9 mg/g DM for 96 h. Rumen GP was recorded after 6, 12, 19, 24, 48, 72 and 96 h of incubation. Interaction effects were observed (P<0.01) between treatment type and yeast dose for the asymptotic GP and methane (CH4) production. Incubation of yeast CE improved (P<0.01) the asymptotic GP compared to control and LC with greater effects (P<0.01) for the low and the intermediate doses. Yeast CE treatment was more effective (P<0.01) in GP than both of LC and control treatments with greater effect (P<0.01) for the low and the intermediate doses. Treatment type and yeast dose affected (P<0.01) CH4 production, metabolisable energy (ME), and short chain fatty acids (SCFA) without affecting in vitro DM degradability (IVDMD). Higher values (P<0.01) of CH4, ME, SCFA and IVDMD were observed for the yeast CE treatment. It could be concluded that adding yeast S. cerevisiae (CE and LC extract) improved GP and ruminal fermentation parameters, where CE at 0.3 and 0.6 mg/g DM was more effective than the yeast LC.

The aim of this study was to determine the effects of increasing levels of two feed additives composed of Salix babylonica (SB) extract and minerals mixture (MM) or their combination on in vitro gas production (GP) and dry matter (DM) degradability of total mixed ration (TMR; 50 concentrate: 50 corn silage, on DM basis). Combinations of four levels of SB extract (0, 0.6, 1.2 and 1.8 mL/g DM) with four levels of MM (0, 0.5, 1.5 and 2.5 g/100 g DM) were evaluated in a completely random design. Samples of TMR (1 g) were weighed in 120 mL serum bottles with addition of SB extract and/or MM. Then, 10 mL of particle free ruminal fluid were added followed by 40 mL of the buffer solution. The GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Addition of SB extract, without MM, increased (P<0.05) asymptotic GP (mL/g DM), the rate of GP (/h), GP and DM degradability (DMD). Addition of MM, without SB, increased (P<0.05) b and decreased c and ruminal pH. Increasing the levels of SB increased (P<0.05) b, c, L, and GP in addition to linearly increase (P<0.001) DMD. Increasing levels of MM increased (P<0.05) b and c while decreased pH. An interaction occurred between different SB extract and MM levels: the most effective levels of SB extract and MM on ruminal fermentation and kinetics were 1.8 mL SB extract/g DM and 2.5 g MM/100 g DM.

In a block randomized design, fifty-one Barki ewes weighing 38.0 kg in average and 2-4 years old, were used to study the effect of pre-and post-lambing dietary crude protein level (CP) of concentrates on the milk yield, milk composition and weight of ewes, and performance of their lambs. The treatments comprised supplementary concentrate containing (g/kg dry matter (DM)): (1) 110 CP (low), (2) 130 CP (medium) and (3) 150 CP (high), while Egyptian berseem hay (Trifiolium alexandrinum) was the basal diet. Ewes were weighed individually biweekly, and the number of lambs dropped and nursed by ewes was recorded within 24 h after birth and biweekly subsequently. Newborn lambs were left to suckle their dams freely, except for the period when milk yield was recorded by weighing lambs before and after suckling. Milk yield was estimated once a week. Ewes were fed the experimental diets during the last two months of pregnancy and throughout the lactation period. Ewes fed 110 g CP/kg DM attained peak of milk yield earlier than those fed 130 and 150 g CP/kg DM. Total milk yield, milk fat and milk total solids, and weaning weight, average daily gain and relative growth rate of lambs were higher (P < 0.05) for ewes fed medium and high protein levels compared to those fed low protein level. Suckled milk was affected by protein level (P < 0.05); the rank order was: 110 CP < 130 CP < 150 CP. Milk protein and extractable milk were higher (P < 0.05) for high protein level compared to low protein level but solids-not-fat (SNF) and lamb birth weight were not affected (P > 0.05) by protein level. Lamb sex, and parity and weight at lambing of ewes had no effect (P > 0.05) on suckled milk, extractable milk and milk yield. Whereas lamb sex and parity of ewe had no effect (P > 0.05) on milk composition, ewe lambing weight affected (P < 0.05) milk fat and SNF but not milk protein and total solids (P > 0.05). Weights of ewes during gestation, after lambing (post-partum weight loss) and during lactation were not affected (P > 0.05) by protein level, except at the 3rd month of lactation. Lamb sex, parity and lambing weight had pronounced (P < 0.05) effects on lamb birth weight and weaning weight. It is concluded that 150 g CP/kg DM level pre-and post-partum could be used for improved performance of ewes and their lambs while parity and weight of ewe at lambing should also be given consideration.

The object of this study was to determine the physicochemical and sensory quality of national and imported from New Zealand mutton sold in the highest mutton-selling region in Mexico (Capulhuac, Estado de Mexico). Samples were obtained from 6 wholesale points. In each outlet a piece of longissimus dorsi muscle was bought. The factors evaluated were moisture, protein, fat, objective color (L*, a* y b*) subjective color and shear force. There were differences (P < 0.05) in variables L*, a*, b*, moisture and protein between national and imported meat. There were also differences in the percentage of protein (national 21.27%; imported 20.27%) of fat (national 2.07%; imported 3.37%), and in shear force (national 3.73 kg; imported 2.09 kg). The sensory evaluation was done by 49 consumer judges. Results showed that consumers prefer imported meat over national meat.

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