Luiz Fernando Costa e Silva

The effects of dietary supplementation with enzymatic complexes and plant extracts on weaned piglets were evaluated. Sixty piglets (28 days old) were assigned to six treatments: Control diet (CD); CD with 125 g/ton of Yucca schidigera extract (CDY); CD with 200 g/ton of enzymatic complex (CDE); CD with 400 g/ton of multi-enzymatic complex with emulsifier (CDME); CDE + 125 g/ton YSE (CDE+Y1) and CDE + 250 g/ton YSE (CDE+Y2). Piglets on the CDE+Y1 diet had better feed conversion ratio [...] ABSTRACT The effects of dietary supplementation with enzymatic complexes and plant extracts on weaned piglets were evaluated. Sixty piglets (28 days old) were assigned to six treatments: Control diet (CD); CD with 125 g/ton of Yucca schidigera extract (CDY); CD with 200 g/ton of enzymatic complex (CDE); CD with 400 g/ton of multi-enzymatic complex with emulsifier (CDME); CDE + 125 g/ton YSE (CDE+Y1) and CDE + 250 g/ton YSE (CDE+Y2). Piglets on the CDE+Y1 diet had better feed conversion ratio

This study was realized to evaluate the influence of monensin, virginiamycin,trace minerals and yeast combination on animal performance, feed efficiency, in situ digestibility, feeding behavior, and carcass and meat characteristics from bulls finished in feedlot fed high-grain diet. A total of 36 (European vs. Nellore) bulls at 24 ± 3.2 months of age and with a body weight (BW) of 385.5 ± 3.84 kg were used in a completely randomized design. The four experimental diets were: CONT – without additives; MONE – inclusion of 30 mg of monensin/kg of DM; MOVI – inclusion of 30 mg of monensin + 30 mg of virginiamycin/kg of DM; MOMY – inclusion of 30 mg of monensin/kg of DM + 0.3 g/kg of BW of trace minerals and yeast. Final body weight was higher (P < 0.05) for the bulls fed MOVI (558.7 kg) and MOMY (554.6 kg) diets, intermediate for bulls fed MONE (529.3 kg) diet, and lower for bulls fed CONT (514.6 kg) diet. Likewise, the average daily gain was higher (P < 0.01) for bulls fed MOVI and MOMY (2.02 kg/d), intermediate for bulls fed MONE (1.72 kg/d), diet and lower for bulls fed CONT (1.57 kg/d) diets. Dry matter intake and other nutrients were similar (P > 0.05) among treatments. However, feed conversion improved (P < 0.05) for bulls fed MOVI and MOMY diets. Animals fed MOVI and MOMY spent more time ruminating compared to animals fed CONT and MONE (P = 0.034) diets. The carcass weights, carcass dressing and backfat thickness were greater (P < 0.05) for the bulls fed MOVI and MOMY diets. In conclusion, the inclusion of monensin or a combination of monensin + virginiamycin or monensin + trace minerals and yeast resulted in higher animal performance and improved feed efficiency.

This study assessed carcass characteristics and meat quality of bulls finished in individual pens and fed with different diets. A completely randomized design determined how to feed 24 crossbred bulls (European × Nellore) with four diets over 84 days: CONT) without additives; MONE) inclusion of 30 mg of monensin/kg DM; MO + VI) inclusion of 30 mg of monensin + 30 mg of virginiamycin/kg DM; and MO+AD) inclusion of 30 mg of monensin/kg DM + 1.57 g of a blend of organic trace minerals, live yeast, beta-glucan, and mannans per kg DM (Advantage-Confinamento). MO+VI resulted in lower pH (P < 0.05) and lighter meat (P < 0.05) compared with other treatments. Cooking loss was less (P < 0.05) with MO+AD at 14 days of aging time. At 14 days, Warner-Bratzler shear force was higher for meat from bulls fed with CONT and MONE diets and slower (P < 0.05) for meat from bulls fed with MO+VI and MO+AD diets. In conclusion, including monensin combined with virginiamycin and monensin combined with a blend of organic trace minerals and yeast in the diets of bulls finished in individual pens can improve the color, Warner-Bratzler shear force of meat, and lower cooking losses.

Objective: Objectives were to estimate energy and protein requirements of dairy crossbred steers, as well as to evaluate equations previously described in the literature (HH46 and CS16) to predict the carcass and empty body chemical composition of crossbred dairy cattle.Methods: Thirty-three Holstein × Zebu steers, aged 19 ± 1 months old, with an initial shrunk body weight of 324 ± 7.7 kg, were randomly divided into three groups: reference group (n = 5), maintenance level (1.17% BW; n = 4), and the remaining 24 steers were randomly allocated to 1 of 4 treatments. Treatments were: intake restricted to 85% of ad libitum feed intake for either 0, 28, 42, or 84 d of an 84-d finishing period.Results: The net energy and the metabolizable protein requirements for maintenance were 0.083 Mcal/EBW0.75/d and 4.40 g/EBW0.75, respectively. The net energy (NEG) and protein (NPG) requirements for growth can be estimated with the following equations: NEG (Mcal/kg EBG) = 0.2973(± 0.1212) × EBW0.4336(± 0.1002) and NPG (g/d) = 183.6(± 22.5333) × EBG – 2.0693(± 4.7254) × RE, where EBW = empty body weight, EBG = empty body gain, and RE = retained energy. Crude protein (CP) and ether extract (EE) chemical contents in carcass, and all the chemical components in the empty body were precisely and accurately estimated by CS16 equations. However, water content in carcass was better predicted by HH46 equation.Conclusion: The equations proposed in this study can be used for estimating the energy and protein requirements of crossbred dairy steers. The CS16 equations were the best estimator for CP and EE chemical contents in carcass, and all chemical components in the empty body of crossbred dairy steers, whereas water in carcass was better estimated using the HH46 equations.

Este trabalho foi realizado para avaliar o efeito da combinação da monensina, virginiamicina e micros minerais + leveduras (Avantage-Confinamento®) sobre o hemograma, estresse oxidativo e atividade antioxidante no plasma sanguíneo, fígado e músculo de bovinos alimentados com dieta alto grão. Um total de 36 touros (Europeu vs. Nelore), com idade média de 24 ± 3,2 meses e peso vivo médio inicial de 385,5 ± 3,84 kg foram distribuídos em um delineamento inteiramente casualizado, com quatro dietas e nove repetições por dieta. A dieta basal foi composta por 850 g/kg de MS de concentrado e 150 g/kg de MS de silagem de milho, fornecida ad libitum por 84 dias. A composição da dieta foi a mesma para todos os animais. As quarto dietas foram: CONT – dieta basal; MONE – dieta basal e inclusão de 30 mg/kg de matéria seca de monensina; MO+VI – dieta basal e inclusão de 30 mg/kg de monensina + 30 mg/kg da matéria seca de virginiamicina; MO+AD – dieta basal e inclusão de 30 mg/kg de monensina + 3,0 g/kg da matéria seca de micros minerais e Saccharomyces cerevisiae (Advantage™ Confinamento). Dentre as variáveis relacionadas ao perfil bioquímico, houve alteração no volume corpuscular médio, creatinina e ureia ao longo dos dias de confinamento. Os parâmetros de avaliação do fígado, avaliado por marcador oxidativo e antioxidante não foram influenciados pelas dietas experimentais. Para os parâmetros de avalição do estado oxidativo na carne, observou-se que inclusão dos aditivos reduziu o dano oxidativo, descarbonilação da proteína muscular, e que os bovinos alimentados com dietas suplementadas com monensina + virginiamicina ou monensina associada com microminerais + leveduras aumentaram a concentração muscular de GSH, em comparação a dieta CONT e MONE.

International committees that have published nutrient requirements for dairy cattle have used data from mineral studies conducted in the 1920s to 1970s, and no study has reported data from animals less than 100 kg; therefore, there is a need to update mineral requirements for preweaned dairy calves. Thus, a meta-analysis was performed to estimate the mineral requirements of Ca, P, K, Mg, and Na for Holstein and Holstein × Gyr crossbred preweaned dairy calves using data from 5 studies developed at the Universidade Federal de Viçosa (Viçosa, MG, Brazil). A total of 210 calves were separated into 2 breeds: purebred Holstein calves (animals with a Holstein pedigree higher than 87.5%) and Holstein × Gyr crossbred calves (animals with a Holstein pedigree lower than 87.5%). The comparative slaughter technique was used to estimate animal body composition and empty body weight (EBW). Mineral requirements for maintenance were estimated by the regression between retained mineral and mineral intake, whereas mineral requirements for gain were obtained from the first derivative of the mineral content in the animal's body. In addition, breed effect was tested on the intercept and slope of the models. The effect of breed was not observed for all analyzed variables. Thus, net requirements for maintenance were 12.73, 11.81, 20.28, 3.50, and 6.37 mg/kg of EBW per day for Ca, P, K, Mg, and Na, respectively. Retention coefficients were 73.18, 65.20, 13.16, 29.55, and 24.28% for Ca, P, K, Mg, and Na, respectively. The following equations were determined to estimate net requirements for gain (NRG, g/d): NRG for Ca = 14.402 × EBW^-0.139 × empty body gain (EBG); NRG for P = 5.849 × EBW^-0.027 × EBG; NRG for K = 1.140 × EBW^-0.048 × EBG; NRG for Mg = 0.603 × EBW^-0.036 × EBG; and NRG for Na = 1.508 × EBW^-0.045 × EBG. Due to the high variation between the data found in this study and in the available literature, we suggest that further studies should be conducted to evaluate the estimates of this study.

Water is the most important nutrient in animal nutrition; however, water intake is rarely measured. The objective of this study was to determine whether previously published water intake (WI) equations for beef cattle would accurately predict WI from four experiments conducted under tropical conditions. The experiments were conducted from 2013 to 2015. Nellore (Bos indicus) growing bulls (Exps. 1, 2, and 3) and heifers (Exp. 4) were used in the feedlot trials. In all experiments, animals were fed for ad libitum DMI. The WI, animal performance, diet composition, and environmental data were collected. The prediction of WI using the current published WI equations was evaluated by regressing predicted and measured WI values. The regression was evaluated using the two-hypothesis test: H0: β0 = 0 and H0: β1 = 1 and Ha: not H0. If both null hypotheses were not rejected, it was concluded that the tested equation accurately estimated WI. To develop a WI prediction equation based on the input variables, a leave-one-out cross-validation method was proposed. The proposed equation was evaluated using similar methodology described above. All previously published eight equations overestimated WI of cattle used in the four experiments conducted in southeast Brazil. A possible explanation for the overestimate of WI is that previously published WI equations were generated from data collected from predominantly Bos taurus cattle raised under temperate climates. From the data collected from experiments conducted with Nellore cattle in southeast Brazil, the proposed equation (WI = 9.449 + 0.190 × MBW + 0.271 × T_MAX −0.259 × HU + 0.489 × DMI, where the MBW is the metabolic BW (kg^0.75), T_MAX is the maximum temperature (°C), HU is the humidity (%) and DMI in kg/d), more accurately to predicts WI of cattle raised under tropical conditions.

The aim of this study was to compare the in vitro digestibility of dry matter (IVDMD) and neutral detergent fiber (IVNDFD) using 2 buffer solutions with or without urea addition. The study was comprised of 2 separate experiments. In both experiments, the treatments were composed of Kansas or McDougall’s buffer solutions with or without urea addition, according to a 2 × 2 factorial arrangement. In Exp. I, the IVDMD and IVNDFD of 25 forages and 25 concentrates were evaluated. Samples were incubated for 48 h using an artificial fermenter and nonwoven textile filter bags (100 g/m²). In this experiment, the repeatability and discriminatory power among samples were calculated within forage or concentrate samples, for each treatment. In Exp. II, Tifton hay and ground corn samples were incubated for 48 h. The pH and ammonia nitrogen (NH₃-N) concentration were measured after 0, 3, 6, 12, 18, 24, and 48 h of incubation. In Exp. I, the interaction between buffer solution and urea addition impacted the IVDMD and IVNDFD of forages (P < 0.05), with greater values being exhibited when using McDougall’s buffer with urea (P < 0.05). For concentrates, the effect of buffer and urea interaction did not affect IVDMD and IVNDFD (P > 0.05). However, greater IVDMD and IVNDFD were observed for McDougall’s buffer (P < 0.05), while urea addition increased IVDMD and IVFDFD estimates (P < 0.05) regardless of buffer solution used. In general, repeatability of the digestibility was better using McDougall’s buffer and improved when urea was added. Urea addition also decreased the discriminatory power among samples for both buffers. In Exp. II, a buffer solution × urea addition × incubation time interaction was detected (P < 0.05) for pH and NH₃-N in both Tifton hay and ground corn. Kansas buffer exhibited lower pH values with a greater decrease observed throughout incubation time when compared to McDougall’s buffer. The use of Kansas buffer with urea addition was the only treatment exhibiting NH₃-N accumulation throughout incubation. In conclusion, McDougall’s buffer provides both better conditions for in vitro fiber digestion and greater precision in digestibility estimates, and is recommended over Kansas buffer. In spite of urea addition increases the precision of in vitro digestibility estimates, it decreases discriminatory power among samples.

SUMMARY: The objective of the current study was to quantify the dry matter (DM) digestibility, and total ash (TA) and mineral release from 12 concentrate and 12 forage feedstuffs commonly fed to cattle usingin situandin vitromethods. Concentrate and forage feedstuffs were incubated in the rumen of ruminally cannulated beef bulls at eight different time points. Two different trials were conducted for concentrates and forages, with maximum incubation time of 72 and 120 h, respectively. The residue from samples incubated for 24 h were treated with pepsin and hydrochloric acid to simulate abomasum digestionin vitro. The initial and residual samples afterin situandin vitroincubations were measured. An asymptotic model was adopted for estimating solubility of minerals, disappearance rate of DM, and TA. Correlations between feedstuff contents and mineral release were evaluated. Residual samples from rumen fermentation after 24 h were incubated in simulated abomasal conditions and mineral release was measured. Cluster analysis was performed to group feedstuffs in relation to TA release. Large variability was observed between concentrate and forage feedstuffs for all constituents analysed. Large variability was observed for the effective ruminal degradation of TA and individual mineral release. When feedstuffs were clustered according to the immediately soluble fraction (‘a’), the insoluble by potentially releasable fraction (‘b’) and the release rate of ‘b’ (‘kd’,/h) estimates of TA ruminal release, four groups were identified. From group ‘1’ to group ‘4’, an increase in the soluble fraction and a reduction in both moderate releasable fraction and release rate was observed. Neutral detergent fibre content had a negative correlation with mineral release in the rumen, while mineral content had a positive correlation. These results demonstrate that mineral solubilization in the digestive tract is not the limiting factor for mineral absorption from the feedstuffs tested.

Summary: There is little information regarding the nutritional requirements for dairy heifers, leading the majority of nutrient requirement systems to consider dairy heifers to be similar to beef heifers. Therefore, we evaluated the muscle protein metabolism and physical and chemical body composition of growing Holstein × Gyr heifers and estimated the energy and protein requirements. We performed a comparative slaughter experiment with 20 Holstein × Gyr heifers at an initial body weight of 218 ± 36.5 kg and an average age of 12 ± 1.0 months. Four heifers were designated as the reference group, and the 16 remaining heifers were fedad libitum. The 16 heifers were distributed using a completely randomized design in a 2 × 2 factorial arrangement with two roughages (corn silage or sugarcane) and two concentrate levels (30 or 50%) for 112 days. Greater (p < 0.05) values for fractional rates of muscle protein synthesis, degradation and accretion were observed for heifers that were fed 50% concentrate. The following equations were obtained to estimate the net energy for gain (NE_g) and net protein for gain (NP_g):NE_g(Mcal/day) = 0.0685 × EBW^0.75 × EBWG^1.095andNP_g(g/day) = 203.8 ×EBWG − 14.80 × RE, respectively, in whichEBWis the empty body weight,EBWGis the empty body weight gain andREis the retained energy. We concluded that increased rates of proteinturnoverare achieved when a greater quality diet is provided. In the future, these results can be used to calculate the nutritional requirements for growth of Holstein × Gyr heifers after equation validation rather than using the recommendations provided by other systems, which use values developed from beef heifers, to determine the nutritional requirements of dairy cattle.