Lipid supplementation may adversely affect rumen fermentation, microbial abundance, nutrient utilization and the duodenal flow of fatty acids (FA). In a 5 × 5 Latin square design, 10 Nellore steers with ruminal and duodenal cannulas (292 ± 28 kg BW) were fed one of the five following dietary lipid sources in the concentrate, as follow: (1) no additional fat (WF); (2) palm oil (PO) derived from the Palmaceae plant Orbignya oleifera; (3) linseed oil (LO); (4) protected fat (PF); and (5) whole soybeans (WS). The dry matter intake (DMI) was greater for the animals supplemented with WF than for those supplemented with PO, PF, and WS. The DM digestibility was 11% greater for the animals in the WF group than for those in the PO group. The animals in the PO group had greater duodenal flows of capric (C10:0), lauric (C12:0) and myristic (C14:0) saturated fatty acids (SFA) than did animals in the other groups. The amount of flows of vaccenic acid and total unsaturated acids (UFA) was greater with LO supplementation. The unsaturated fatty acid (UFA) biohydrogenation ratio was greater in the animals supplemented with WS than in those supplemented with PO, LO, and PF. The acetate: propionate ratio was lower in the animals supplemented with PO and LO, at 2.9 and 3.0, respectively. The ruminal flow of particles and rate of fiber degradation were lower with PO supplementation. The proportion of archaea was reduced with the inclusion of PO, LO and PF. PO supplementation resulted in lower total apparent NDF digestibility than did WF, PF, and WS supplementation. Therefore, LO, PF and WS can be used as dietary supplements for grazing cattle without impairing fermentation. The inclusion of PO in the diets of grazing cattle may reduce the number of methanogens and alter fiber utilization.

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-The objective of this study was to evaluate the effect of lipid sources on voluntary intake, digestibility, performance, and CH 4 emission of Nellore steers grazing Brachiaria brizantha cv. Xaraés forage in the dry season. Forty-five Nellore steers with average weight of 442±34 kg were alloted into one of the five treatments: without additional fat; with palm oil; with linseed oil; with protected fat; and with whole soybeans. The supplements were provided daily and quantities were adjusted to 1% of body weight and diets were formulated in accordance with the Cornell Net Carbohydrate and Protein System. The experimental design was completely randomized with five treatments and two replications. There were no effects on dry matter, organic matter, and neutral detergent fiber intake with the inclusion of lipids in the diet. The neutral detergent fiber showed decreased digestibility in animals receiving linseed oil and palm oil treatments compared with animals receiving the diet without additional fat. The linseed oil treatment reduced CH 4 emissions by 38% when expressed in mg/d/kg BW and tended to reduce the emission in g/d/kg BW 0.75 . Lipid sources did not affect the weight gain of the animals. The intake and performance of grazing Nellore steers supplemented at 1% body weight with lipid sources were not modified. However, fiber digestibility was reduced with palm or linseed oil addition. Linseed oil reduced enteric CH 4 emissions. Linseed oil has the potential to reduce enteric CH 4 emissions in continuous tropical grazing systems based on B. brizantha grass.

The effects of glycerol with fat sources as a feed alternative were investigated in the ration for Nellore steers (Bos indicus). Eight cannulated steers at 30 months of age with initial bodyweight of 554 ± 36.0 kg were used in a double 4 by 4 Latin square design with four consecutive 16-day periods. Treatments were three different diets with lipid sources (soybean, soybean oil and calcium salts of fatty acids) and one diet control without lipid sources. All diets formulated contained 10% crude glycerol and 5% ether extract with a forage:concentrate ratio of 35:65; corn silage was used as forage. The ruminal liquid was sampled for 24 h and ruminal fermentations were monitored by measuring pH, concentrations of ammonia nitrogenand volatile fatty acids in rumen fluid. Urine samples were obtained from the total collection for 24 h for estimation of rumen microbial protein supply using urinary purine derivatives. Our results showed that the use of lipid sources combined with glycerol did not induce significant changes in rumen pH, acetate molar proportion, ruminal microbial protein or dry matter intake. Although the acetate molar proportion was kept constant within normal parameters, the propionate molar proportion was increased by the diet containing lipid sources. Moreover, we found that there was a negative effect of lipid sources on crude protein and neutral detergent fibre corrected for ash and protein intake, and one positive effect on ether extract intake. We believe that association between fat and glycerol may affect rumen fermentation parameters through reducing fibre intake and increasing propionate production and ammonia nitrogen.

Background: Intensification of livestock is a strategy that increases productivity, but the diets used to increase animal production efficiency are composed mainly of corn and soybean, thereby increasing competition between animals and humans for the same food crops. This study evaluated nutrient intake, apparent digestibility of dry matter (DM) and nutrients, kinetics of gas production, and concentration of volatile fatty acids on diets with or without inclusion of biodiesel co-products formulated for feedlot lambs. So, the hypothesis is that replace of traditional ingredients by biodiesel co-products changes rumen parameters and methane emissions.Material, Methods & Results: The experiment was developed in São Paulo State University (Unesp), Jaboticabal/SP, Brazil, in Sheep Production Laboratory, which is owned to Animal Science Department. All trials developed in this study used a feedlot system, where animals were kept in individual pen. Forty Ile de France lambs male non-castrated were used in in vivo trial. To obtain rumen fluid, that was used in in vitro trial, four Santa Inês lambs with rumen cannula were used. The treatments evaluated were four diets: Control diet: roughage + concentrate; PM20: roughage + concentrate with peanut meal (PM) at 20% of DM; CG25: roughage + concentrate with crude glycerin (CG) at 25% of DM; and PMCG: roughage + concentrate with PM at 10% of DM and CG at 12.5% of DM. The roughage:concentrate ratio was 40:60 for all these diets. The parameters of the in vitro and in vivo experiments used were completely randomized with four treatments. When significant, the means between treatments were compared using Tukey test (P < 0.05). There was no effect of co-product inclusion on intake, except ether extract and neutral detergent fiber, which were higher for PM20 compared with CG25 diet. Apparent digestibility of dry matter (79.87%) and some nutrients (organic matter, crude protein, and neutral detergent fiber) was higher (P < 0.05) with CG25 diet. In vitro cumulative gas production was greater in CG25 and PMCG compared to the other diets, at early measurement points (2, 4, 6, and 10 h). The concentrations of methane, volatile fatty acids, and acetate:propionate ratio in vitro did not differ (P > 0.05) among diets.Discussion: Probably the high quality of the glycerin used (83.9% glycerol, 12.01% humidity, 3.79% salts, and 0.28% organic matter, no fat, as described by the manufacturer) may explain the low EE concentration observed in the diet using only crude glycerin and the observed lack of DMI effects in all diets. About apparent digestibility, the greater values measured for crude protein can be explained by superior synchronism during fermentation of the proteins and carbohydrates in the diet. The data showed that treatment CG25 obtained higher initial gas production, followed by treatment PMCG which contained 12.5% crude glycerin. Probably these results were caused by the greater apparent digestibility of DM in treatments that included crude glycerin. Our results of volatile fatty acid concentration are different from the decrease in molar proportion of acetic acid and increase of propionic acid described by several authors, with the inclusion of glycerin in the diet. However, the absence of effect by co-product inclusion on the molar proportion of acetic, propionic, and butyric acids measured in this trial reinforce the report from other authors that affirmed the same situation. Hence, the inclusion of PM at 20% of DM and CG at 25% of DM could successfully replace the traditional diets of feedlot lambs such as soybean and corn, respectively, without damages to intake and ruminal parameters in vitro.

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The objectives were to evaluate the effects of monensin and virginiamycin, alone or combined, on supplemented Nellore cattle grazing tropical grass during the rainy season. Two experiments were conducted simultaneously to evaluate intake, digestibility, CH 4 emissions, blood parameters, performance, and carcass characteristics (Exp. 1), and ruminal fermentation and relative abundance of ruminal microorganisms (Exp. 2). Animals (n = 92 Exp. 1 and n = 12 Exp. 2) were distributed in a completely randomized design and allocated in twelve paddocks composed of Urochloa brizantha (A. Rich.) Stapf. cv. Xaraés. A protein-energetic supplementation of 3 g/kg of BW per day was provided to all animals. Supplements were: without additives (WA), monensin alone at 80 mg/kg of product (MN), virginiamycin alone at 150 mg/kg of product (VM), and monensin (80 mg/kg of product) combined with virginiamycin (150 mg/kg of product; MNVM). Treatments did not affect intakes of total dry matter (DM), supplement DM, and nutrients. However, the intakes of forage DM and crude protein decreased in cattle fed MNVM compared with animals fed WA, MN, and VM. Total volatile fatty acids increased in animals fed VM. Ruminal NH 3 -N decreased, and pH increased in animals fed MN, VM, and MNVM. Relative abundance of total F. succinogenes and S. ruminantium decreased and R. flavefaciens increased in animals fed MN and VM at d 118. Treatments had no effect on enteric CH 4 emissions. The average daily gain (ADG) and total gain were greater in cattle fed MNVM than in cattle fed MN. Combination of monensin and virginiamycin altered the rumen microbial populations but did not decrease enteric CH 4 emissions. However, it decreased forage dry matter intake without altering the ADG and total weight gain, leading to an increase in feed efficiency. Results from this study indicate an advantage in including feed additives combined in the diet of supplemented Nellore cattle grazing tropical grass during the rainy season.

This study evaluated the effect of phosphorus (P) supplementation on the intake, digestibility, and quality of aged meat from Nellore young bulls fed on high-grain diets finished in feedlot. Forty young bulls (30 months old) with an initial body weight (IBW) of 296 ± 25 kg were used. It was distributed in a completely randomized experimental design. The treatments were: without P supplementation (CO), commercial mineral supplement (CM), and supplementation with dicalcium phosphate (DP) with 2.4, 4.2, or 5.0 g of P per kg of dry matter (DM), respectively. Diets were composed of sugarcane bagasse (200 g kg-1) plus concentrate (800 g kg-1) on a dry matter (DM) basis. The meat quality parameters analyzed were pH, color, cooking losses, shear force, and water-holding capacity. P supplementation did not affect the intake and digestibility of nutrients There was no interaction (p > 0.05%) between diets and the aging time for the meat quality parameters. However, bulls fed with DP exhibited lower pH (5.98) compared to CO and CM (6.19 and 6.14, respectively). The longer aging time increased the cooking losses and intensity of yellow (b*). Under Brazilian conditions, feedlot Nellore cattle fed with high-grain diets do not require additional mineral supplements.