The use of ensiled sugarcane has been increased lately in Brazil due to the benefits that this technique represents. The objective of this study was to evaluate the effects of chemical additives on the nutritive value of sugarcane silages. The trial was carried out in a completely randomized experimental design with four replicates per treatment. The following additives were applied onto the fresh forage before ensiling: L. buchneri, lime or limestone, 1.0 and 1.5% (wet basis) each, and gypsum 1.0% (wet basis), all of them diluted into 40 L of water per ton of fresh weight of forage. The analyzed variables were: ash, crude protein, neutral detergent fiber, acid detergent fiber and organic and dry matter digestibility. The addition of lime or limestone before ensiling produced silages with higher nutritive value compared to all other treatments, due to the increase of the ash content and dry matter and organic digestibility, and also by reducing the fiber content. The crude protein content range was similar to the values observed in the fresh forage. The treatments containing L. buchneri or gypsum were ineffective in improving the nutritive value of sugarcane silages and became similar to the control silages. Treatment containing lime or limestone improved the nutritive value of the sugarcane silage. Key words: calcium carbonate, calcium oxide, calcium sulfate VALOR NUTRITIVO DA SILAGEM DE CANA-DE-AÇÚCAR TRATADA COM ADITIVOS QUÍMICOSRESUMO: A utilização da cana-de-açúcar na forma de silagem constitui-se em um tema que vem se destacando nos últimos anos, e que desperta o interesse de produtores e pesquisadores em função dos benefícios que essa técnica representa. O objetivo do presente trabalho foi avaliar o efeito de aditivos químicos no valor nutritivo da silagem de cana-de-açúcar. O experimento foi desenvolvido em delineamento inteiramente casualizado com quatro repetições por tratamento. Os seguintes aditivos foram utilizados para a confecção das silagens: L. buchneri, cal virgem ou calcário em doses de 1,0 e 1,5% da MV e gesso agrícola a 1,0% da MV, diluídos em 40 litros de água por tonelada de forragem. As variáveis analisadas foram: matéria mineral, proteína bruta, digestibilidade da matéria seca e orgânica, fibra em detergente neutro e fibra em detergente ácido. Para as variáveis de valor nutritivo, as silagens tratadas com cal virgem ou calcário apresentaram, no momento da abertura, maior teor de cinzas, menor concentração de componentes fibrosos e maiores coeficientes digestibilidade da matéria seca e orgânica. O teor de proteína bruta encontrado para esses tratamentos está dentro da amplitude preconizada para a forragem fresca. A ensilagem

Effects of organic and inorganic sources of S on intake, intake pattern, ruminal pH, VFA profile, and ruminal H2S gas concentration ([H2S]) were evaluated, which lead to development of a procedure to measure ruminal S availability for reduction [ruminal available S (RAS)] as well as compare with an estimated number [adjusted ruminal protein S (ARPS)]. Ruminally cannulated crossbred beef steers (n = 5; BW = 548 ± 46 kg) were assigned to 1 of 5 diets in a 5×5 Latin square design and fed ad libitum in five 21-d periods. Steers were fed a dry-rolled corn diet (CON), inorganic S source (ammonium sulfate; INORG), organic S source (corn gluten meal) fed at 9.8 (ORG-L) or 23% of diet DM (ORG-H), or wet distillers grains with solubles (WDGS) fed at 50% of diet DM. For the laboratory procedure, individual ingredients were incubated with ruminal fluid from heifers fed 60% corn-based diets (n = 2) and McDougall's buffer. Bottles were cooled in ice, centrifuged, and decanted, and the precipitate was analyzed for S. Steers fed INORG tended (P = 0.12) to consume 12% less DM. Total S intake was greater (P < 0.01) for steers fed WDGS (60 g/d) followed by ORG-H, and the lowest S intake was observed for CON (22 g/d). Intakes of ARPS and RAS were greater (P < 0.01) for steers fed WDGS followed by INORG, ORG-H, ORG-L, and CON diets. Steers fed WDGS and INORG diets spent 13% more time eating (P < 0.01) compared with other treatments. There was an interaction (P = 0.05) between treatment and time for ruminal [H2S]. Similar [H2S] were observed for steers fed INORG and WDGS diets (P = 0.28), which were greater (P ≤ 0.05) than other treatments. Greater ruminal [H2S] at 8 h compared with 13 h postfeeding was observed for steers fed ORG-H, ORG-L, and CON diets (P ≤ 0.04). Nearly 65% of ruminal [H2S] variation was explained (linear; P < 0.01) by RAS intake, ARPS explained 58% (linear; P < 0.01), S intake explained 29% (quadratic; P < 0.01), average ruminal pH explained 12% (linear; P < 0.01), and area below ruminal pH 5.6 explained 16% (linear, P < 0.01) of the variation. A 6% decrease in acetate (P = 0.01), 20% increase in propionate molar proportions (P = 0.02), and a lower acetate:proprionate ratio (P = 0.02) were observed for steers fed INORG compared with CON diet. The RAS concept is important for predicting ruminal [H2S] rather than just total S in the diet. Coefficients of RAS for individual ingredients can be predicted using in vitro procedures. Ruminal [H2S] may also modulate intake pattern.

Effects of live yeast (Saccharomyces cerevisiae) in steam-flaked corn-based diets fed to natural-program beef cattle on growth performance, total tract apparent digestibility, carcass characteristics, and feeding behavior were evaluated in a randomized block design experiment. Steers (n = 144; 341 ± 7.03 kg) were blocked by initial BW and assigned randomly to 1 of the 3 treatments (n = 12 pens per treatment with 4 steers per pen). Treatments included the following: 1) control (CTL; no yeast); 2) low yeast (LY; 1.5 g/animal daily [3 × 1010 CFU]); and 3) high yeast (HY; 3.0 g/animal daily [6 × 1010 CFU]). Technologies such as implants, ionophores, and antibiotics were not used, and the steam-flaked corn-based finishing diets were fed to provide ad libitum access to feed. Yeast was included in a cottonseed meal-based premix as 1% of the dietary DM. Spot fecal samples (twice daily for 5 consecutive days) and diets were composited by pen and analyzed for acid insoluble ash to estimate apparent total tract digestibility of nutrients. Cattle were slaughtered on days 183 (4 blocks) and 204 (8 blocks). Dry matter intake (P ≥ 0.29), ADG (P ≥ 0.17), and G:F (P ≥ 0.33) did not differ among treatments. The percentage of Premium Choice (P < 0.01) carcasses increased linearly with increasing yeast inclusion in the diet. A quadratic response was observed for total tract apparent digestibility, in which steers fed LY had greater digestibility (P < 0.01) of DM by 5.4%, OM by 4.8%, NDF by 15.2%, ADF by 20.2%, CP by 6.2%, and ether extract (EE) by 2.5% compared with steers fed CTL. Feeding behavior was not affected (P = 0.28) by treatments. Live yeast improved digestibility of DM, OM, CP, EE, and fiber, without changing feeding behavior and growth performance of natural-program steers fed steam-flaked corn-based finishing diets.

Information on the water footprint of pasture‐based beef production is useful for optimizing the allocation of groundwater to crop and livestock production. The objective of this research was to determine the effect of including legumes on three water footprints of grass‐based, beef stocker grazing systems with respect to observed and total (observed plus predicted from hay production) liveweight gain (LWG). Water inputs for the calculations included total or effective rainfall, total or corrected drip irrigation, and water directly consumed by the steers. When including rainfall in the calculation, water footprints were 16.2 to 40.5 vs. 1.7 to 8.6 m3 kg−1 LWG when including groundwater only. Inclusion of legumes into the system reduced each water footprint with respect to observed LWG in all years (P ≤ 0.01). When total LWG was considered, the water footprint was lower in the grass‐legume system if rainfall (total or effective) was included (P < 0.01) but greater if the evaluation was restricted to irrigation and drinking water as inputs (P < 0.01). Overall, including legumes reduced the water footprint of beef LWG, largely because of greater rates of gain from the greater quality forages. Quantifying water use in the stocker phase adds a missing component in evaluating limited resources in the beef production life cycle. Managing legumes in mixture with warm‐season grasses and as a protein bank can increase the efficiency of beef grazing systems, resulting in an overall lower water footprint for animal weight gain.

Forty-seven Zebu calves were used to determine the effects of class (bull or steer), supplementation (SUPPL, a poultry litter-based supplement or mineral supplementation), and implant (20 mg estradiol combined with 120 mg of trenbolone acetate or no implant) on growth and carcass performance and beef eating quality. The average daily gain (ADG) of implanted cattle significantly increased for steers, but not for bulls. The SUPPL treatment increased ADG by 8.63% from day 0 to end, and shortened in 73.3 d the time to reach 480 kg BW (p < 0.01). Compared to bulls, the steer carcasses exhibited more desirable maturity and finish scores, thicker back fat (p < 0.05), and yielded greater (p < 0.01) percentages of high-value boneless subprimals (HVBLS) (+1.64%) and total cuts (1.35%). The SUPPL bulls dressed 2.63 and 1.63% greater than non-supplemented bulls and SUPPL steers, respectively (p < 0.05). Meat sensory quality was subtly affected (p < 0.05) by sex class or supplementation. The implant did not affect (p > 0.05) shear force or sensory ratings. The supplementation improved key growth performance traits while it adversely affected tenderness-related sensory traits. The implant enhanced the rate of gain of steers only, without improving cut-out yields or inducing adverse effects on palatability traits in both steers and bulls.