The objective of this experiment was to evaluate the effect of supplementing increasing levels of Gliricidia sepium hay (GS) with different levels of inclusion of Buffel grass (BG) hay on digestibility by hair sheep lambs (2.5 to 3.5 months of age). Eight male lambs were used in a replicated 4 × 4 Latin square design with 21-day experimental periods (n = 4). Animals were fed with BG with different levels of GS: 100% BG (T1, control), 90% BG + 10% GS (T2), 80% BG + 20% GS (T3), and 70% BG + 30% GS (T4). Dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) intakes were not affected by treatments. The intake of crude protein (CP), organic matter (OM), and gross energy was higher (P < 0.05) in those lambs fed with T4 diet than control. NDF and ADF digestibilities were higher (P < 0.05) in T1 than in the other treatments. CP digestibility was higher (P < 0.05) in T4 compared to T1, T2, and T3. The study showed that inclusion of GS up to 30% with BG in forage-based diets of sheep does not affect DM and fiber intake nor influence DM and OM digestibilities but it increases CP intake and reduces NDF and ADF digestibilities.

The objective of the study was to evaluate the effect of corn stover silages with two sources of energy (cane molasses or milk whey) and EM (effective microorganisms, 1 mL/kg DM) on the digestibility of nutrients and rumen fermentation. We hypothesized that inoculation with EM (lactobacillus spp and Rhodopseudomona palustris and Saccharomyces cerevisiae) in the silage process of corn stover coud improve the in vivo digestibility and ruminal fermentation in sheep. Six male sheep with cannula in the rumen were used in a 6 x 6 Latin square design. Experimental periods consisted of 11 d for diet adjustment followed by 5 d for collection. The animals were housed in metabolic cages, with a harness to collect faeces individually. Diets consisted of concentrate (corn grain, soybean meal, mineral salt) 55% and corn stover 45% dry basis. The treatments were: CS-AMW= Corn stover with acid milk whey, CS-CM= corn stover with sugar cane molasses, SIL-AMW= corn stover silage with acid milk whey, SIL-CM= corn stover silage with cane molasses, SIL-AMW-EM= corn stover silage with acid milk whey and EMand SIL-CM-EM= Corn stover silage with cane molasses and EM. The results were analyzed with PROC MIXED procedures of SAS. The inoculation of corn stover with EM increased (P &lt; 0.05) the content of CP in SIL-AMW-EM and SIL-CM-EM respect CS-CM (Table 1). SIL-CM-EM increase (P &lt; 0.05) the ruminal N-NH3 and pH (Table 2) but no effect was observed for digestibility (Table 3). However, the SIL-AMW improved (5.8%, P &lt; 0.05) the OM digestion compared with CS-AMW. A diet with 45% corn stover silage with EM was not sufficient to improve in vivo digestibility of nutrients in sheep. This project was supported by UNAM,DGAPA, PAPIIT (IT202120)

Four rumen-cannulated cows (Bos taurus × Bos indicus, 657 ± 92 kg body weight, BW) in a rotational grazing (Urochloa sp.) system were assigned to different canola oil (CO) inclusion levels, 0.0, 0.40, 0.80, and 1.2 g/kg according to shrunk body weight (SBW, BW adjusted for gastrointestinal filling) in a 4 × 4 Latin Square design to evaluate CO on the CH4 emissions and dietary energy intake. CH4 emissions were estimated using an infrared analyzer methodology (Sniffer method). Grass intake and fecal production were estimated using Cr2O3 as an external marker. CO supplementation increased (linear effect, P ≤ 0.05) total dry matter and gross energy intake with a linear increase (P = 0.09) in neutral detergent fiber (NDF) intake. While digestible energy (Mcal/kg) linearly increased with increasing CO supplementation level (linear effect, P < 0.05), total tract digestion of organic matter, NDF, and CP was comparable (P > 0.05) between levels. Maximal CO supplementation (1.2 g/kg SBW) significantly decreased total ruminal protozoa population, acetate:propionate ratio, and enteric methane production (g/kg DMI) by 9, 5.3, and 17.5%, respectively. This study showed that, for cows grazing tropical forages, CO can be supplemented up to 1.2 g/kg SBW (5.8% of the total diet) without negatively affecting intake and nutrient digestion while reducing ruminal fermentation efficiency and enteric methane emission (≤ 17.5%).

An experiment was performed to evaluate the effect of canola oil (CO) supplementation at 4 inclusion rates [CO0=0%, CO2=2%, CO4=4%, and CO6=6% of dry matter intake (DMI)] on digestibility, volatile fat acids (VFA), a mmonia nitrogen (NH3-N), protozoa and methane (CH4) emissions, in cows grazing a tropical grass (Brachiaria sp.). Four cows (Bos taurus × Bos indicus) with rumen cannula (658 ± 92 kg) were randomly assigned to a Latin Square design with 4 treatments and 4 periods (19-d each). Treatments were offered daily at 0600 h and 1500 h together with a commercial concentrate (1% of EBW). Fecal output was measured using an external marker (Cr2O3) dosed once per day for 9 days. Fecal output along with digestibility data were used to estimate DMI. Methane production was monitored twice a day, for 5 consecutive-days, using infrared gas analyzers (Guardian Plus) at the time of CO supplementation. Rumen contents were collected at 0300 h and every 4-h during the last 2-d of each period. Data of digestibility were analyzed as a Latin Square using a mixed model procedure (SAS Inst. Inc., Cary, NC). For ruminal fermentation parameters, collection time was considered a repeated measure. Orthogonal polynomials were performed to evaluate linear and quadratic effects. No effect was observed on fiber digestibility, or any nutrient evaluated with up to 6% CO inclusion. Total protozoa (x104cells/mL), methane emission and acetate molar proportion decreased (P &lt; 0.01) while propionate increased (P &lt; 0.01) with consequent reduction on the acetate:propionate ratio (CO0=3.2, CO2=2.8, CO4=2.6, CO6=2.4; P &lt; 0.01) as the level of CO increased. In conclusion, supplementing CO to animals consuming a tropical forage-based diet, may represent a viable option to reduce CH4 emissions without having a negative effect on the digestibility of the NDF.

Four rumen-cannulated cows (Bos taurus × Bos indicus, 631 ± 88 BW) were assigned in a 4×4 Latin Square design to test the effects of different canola oil inclusion levels (CO; 0.0, 0.40, 0.80 and 1.2 g/kg shrunk body weight, SBW = BW×0.96) on the reduction of CH4 emissions and the energy value of the diet based on Brachiaria sp. under rotational grazing supplemented with a fixed amount of concentrate. The CH4 emission was analysed by an infrared analyser. Grass consumption and faecal production were estimated using Cr2O3 as external marker. The CO supplementation increased (linear effect, P < 0.05) DM (16.6%), organic matter (OM, 18.0%) and gross energy intakes (26.3%) and decreased the total digestibility of neutral detergent fibre (NDF) by 26% (linear effect, P < 0.05); also increased digestible energy value (Mcal/kg) by 7.1%. In the rumen, the maximum oil inclusion level decreased the total protozoa population by 89%, the acetate: propionate ratio by 25% and the enteric methane production by 18.9%, all without negatively affecting any of the other variables of fermentation and digestion evaluated. It is concluded that canola oil at supplementation levels of up to 1.2 g CO/kg SBW (5.3% of the total diet) for cows grazing tropical forages supplemented with concentrates increases the total and energy consumption and the efficiency of ruminal fermentation, thereby reducing the emission of enteric methane by up to 18.9%.