Alexandre Vaz Pires

Desempenho e características da carcaça de cordeiros confinados alimentados com grãos de soja

The objective of this work was to evaluate the effects of raw soybean on lamb performance, carcass yield and lamb cuts. Raw soybean was added at 0, 7, 14 and 21% of the diet dry matter (isonitrogenous). Sixty-four Santa Ines lambs (initial body weight 19.5±0.19 kg and 75±2 days old) were assigned to a complete randomized block design according to body weight and age at beginning of the trial. Dry matter intake (1.1, 1.0, 0.9 and 0.9 kg per day), crude protein intake (199.2, 181.5, 179.0 and 175.2 g per day) and average daily gain (298, 275, 280, 255 g per day) decreased linearly, and ether extract intake (43.8, 49.7, 57.2 and 66.0 g per day) increased linearly, as levels of raw soybean increased. Feed conversion, carcass yield and lamb cuts were not affected by raw soybean inclusion in the diet. The inclusion of raw soybean in high concentrate diets provides satisfactory feedlot lamb performance.

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay.

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P < 0.01), which was associated with a greater partial efficiency of energy retention as fat (P < 0.01). This increased nutritional efficiency, however, should be viewed with caution because it is related to visceral fat deposition, a nonedible tissue.

Comportamento ingestivo de ovinos e digestibilidade aparente dos nutrientes de dietas contendo casca de soja

Twoxa0trials were performed to evaluate the effects of replacing coastcross hay by soybean hulls on ewe lambs ingestive behavior and diet digestibility. In the first trial, forty-eight ewe lambs (23.1xa0kg initial BW and 124xa0days old) were assigned to a randomized block design. The control diet contained 50% coarsely chopped coastcross hay and no soybean hulls. In the remaining treatments, soybean hulls replaced hay by 12.5%, 25% or 37.5% on dry matter (DM) basis. Eating and ruminating times were determined every five min during 24xa0hours. There was a decreased linear effect for ingestive (eating, ruminating and total chewing) behavior as soybean hulls were added to the diet. In the second trial, four Santa Ines ram lambs were arranged in a 4x4 latin square design and fed the same treatments as in the first trial. There was an increased linear effect of soybean hulls on DM, organic matter (OM), NDF and hemicellulose intake and digestibilities. ADF intake also increased linearly. Soybean hulls contains lower NDF physical effectiveness as compared to coastcross hay and its addition up to 37.5% of the diet DM improved OM and DM digestibilities.

Growth, feed intake, carcass characteristics, and eating behavior of feedlot lambs fed high-concentrate diets containing soybean hulls.

The objectives of this experiment were to determine the effects of replacing ground corn with soybean hulls (SH) in high-concentrate diets on the growth (56-d period), carcass characteristics, and eating behavior of feedlot lambs. Sixty-four Santa Inês ram lambs (18.3 ± 2.8 kg of BW and 69 ± 5 d of age) were assigned to a randomized complete block design experiment with 8 blocks and 4 diets. The control diet contained 10% coastcross (Cynodon sp.) hay, 70% corn, and no SH (SH0) in the dietary DM. In the remaining diets, SH replaced corn at the rate of 15 (SH15), 30 (SH30), or 45% (SH45) of the original corn concentration, resulting in 0, 10.5, 21.0, or 31.4% SH in the dietary DM. Dry matter intake increased linearly (P < 0.01) when SH replaced ground corn (1.0, 1.0, 1.1, and 1.1 kg/d for SH0, SH15, SH30, and SH45, respectively). There was no effect on ADG of lambs, with values of 276, 278, 282, and 287 g for SH0, SH15, SH30, and SH45, respectively. Feed efficiency decreased linearly (P < 0.01) with SH inclusion. Carcass measures were not affected by SH as a replacement for ground corn. Eating time, expressed as minutes per day and minutes per gram of NDF, showed a quadratic effect (P < 0.05), whereas no effect was observed when expressed as minutes per gram of DM. Rumination, in minutes per day, was not influenced by dietary SH inclusion, but a linear decrease (P < 0.01) was observed when this variable was expressed as minutes per gram of NDF. Soybean hulls can replace up to 45% of the ground corn (31.4% of SH in the dietary DM) in high-concentrate diets fed to feedlot lambs without negative effects on ADG and carcass measures. The linear decrease in feed efficiency (11.6% reduction from SH0 to SH45) suggests that optimal dietary SH inclusion rates should be dictated by the relative costs of SH and corn.

Desempenho de cordeiros e estimativa da digestibilidade do amido de dietas com diferentes fontes protéicas

Oxa0objetivo deste trabalho foi avaliar a influencia de fontes proteicas sobre desempenho, caracteristicas da carcaca e da carne de cordeiros confinados, e estimar a digestibilidade do amido de racoes com alta proporcao de graos. Foram distribuidos 28xa0cordeiros Santa Ines, em blocos completos ao acaso, de acordo com o peso vivo e a idade, no inicio do experimento. Asxa0fontes proteicas foram os farelos de: soja, amendoim, canola e algodao, em dietas isonitrogenadas com 90% de concentrado e 10% de volumoso (feno de coast-cross). Naxa0determinacao da digestibilidade, foram utilizados quatro borregos em delineamento experimental em quadrado latino 4x4, e a digestibilidade do amido foi estimada a partir do teor de amido fecal. Nao houve diferencas (p>0,05) quanto ao consumo de materia seca, ganho de peso vivo medio, conversao alimentar, caracteristicas da carcaca e da carne, entre as fontes proteicas avaliadas. Axa0digestibilidade do amido apresentou coeficiente de determinacao de 93%. Independentemente da fonte proteica utilizada, o teor de amido nas fezes e um indicador eficiente na estimativa da digestibilidade do amido de dietas com alta proporcao de concentrado para cordeiros.

Substituição do farelo de soja por uréia ou amiréia na dieta de bovinos de corte confinados

The objective of this work was to evaluate the effects of replacing soybean meal by urea or starea on feedlot cattle performance. Eighty-one yearling intact males (27 Nellore, 27 Canchim and 27 Holstein) were used, with initial body weight of 250xa0kg. Animals were assigned to a completely random block design according to initial weight and breed. There were nine pen/treatment with three animals/pen. Experimental treatments were: 1) soybean meal, 2) urea and 3) starea. Diets contained 13% CP and were composed of 80% concentrate and 20% raw sugarcane bagasse. DMI was 6.56, 7.18 and 6.97xa0kg/day, average daily gain was 0.889, 1.114 and 1.088xa0kg/day and feed conversion was 7.3, 6.5 and 6.7xa0kg DM/kg gain for soybean meal, urea and starea, respectively. Soybean meal reduced (P 0.05) between urea and starea treatments.

Fontes protéicas e de amido com diferentes degradabilidades ruminais para alimentar vacas leiteiras

The objective of this work was to evaluate starch sources (fine ground x popped corn) and protein sources (soybean meal x fish meal x urea) varying in rumen degradability in order to feed dairy cows. Fifty-six Holstein cows averaging 112 days in milk were used. The treatments were: MFS (fine ground corn + soybean meal); PFS (popped corn + soybean meal); PFP (popped corn + soybean meal + fishmeal) and PU (popped corn + soybean meal + urea). The treatment PFS did not affect milk yield, but it decreased milk fat content, milk fat yield and milk protein content, compared to MFS. Milk yield was higher for PFS than for PFP or PU. Treatment with fishmeal (PFP) decreased milk fat content, milk fat yield and 3.5% FCM yield, but increased milk protein content.

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

The objective of this study was to evaluate the characteristics of ruminal fermentation and enteric methane production in beef cattle subjected to different supplementation frequencies while grazing on Brachiaria brizanthacv. Marandu pastures. Nine cattle (325±65.7 kg BW) fitted with ruminal and duodenal cannulas were used in the ruminal fermentation study, and 12 cattle (399±32.6 kg BW) were used in the enteric methane production study. The treatments included supplementation once daily, supplementation once daily except Saturdays and Sundays, or supplementation on alternate days. The supplementation was equivalent to 10 g kg−1 BW day−1 for all treatments. The design employed was completely randomized with three treatments and three replications. When all supplements were provided (day 1), no effects of supplementation frequency were observed on ruminal pH; concentration of NH3-N; concentration of acetic, propionic, or butyric acids; or total volatile fatty acids (VFA), but there were month effects. During the day on which only daily supplements were provided (day 2), significant differences were observed only on the molar concentration of acetic acid and total VFA; and month effects were noted on all variables. No significant differences were observed in ruminal fluid volume, dilution rate, N intake, bacterial N synthesis and enteric methane production among the studied supplementation frequencies. Differences were observed in the enteric methane production in the different months, with 85 g kg−1 of gross energy intake observed in September and 123 g kg−1 of gross energy intake observed in November. Lower supplementation frequency is a good option to lower labor costs with little or no consequences on ruminal fermentation characteristics and enteric methane production.

Apparent digestibility, nitrogen balance, and ruminal constituents in ram lambs fed high-concentrate diets containing soybean hulls

Corn often constitutes the main portion of high-concentrate diets fed to feedlot lambs. However, soybean hulls (SH) may be used to replace corn, and may reduce feed costs and the risk of acidosis. The objective of this experiment was to determine the effect of SH inclusion rate in high-concentrate diets on DMI, apparent digestibility of nutrients, N balance, and some rumen constituents. Sixteen ruminally fistulated Santa Inês ram lambs (44.3 ± 5 kg of BW and 6 mo old) were housed in suspended metabolism crates. A randomized complete block design experiment with 4 diets and 4 blocks was used. Blocks were defined by BW, and diets were allotted randomly within block. The control diet contained 70% corn and 0% SH. In the remaining diets, SH replaced corn at the rate of 15, 30, or 45% of the original corn concentration, which resulted in 0, 10.5, 21.0, and 31.4% of SH in the dietary DM. The DMI (kg/d) increased linearly (P < 0.01) with increasing dietary SH inclusion. A trend was observed for linear decreases (P = 0.10) in apparent DM, OM, and nonfiber carbohydrate digestibility, and a trend was observed for an increase (P = 0.08) in NDF digestibility with increasing dietary SH addition. Apparent digestibilities of CP and ether extract and ADF digestibility were not affected by SH inclusion rate. Total ruminal concentration of short-chain fatty acids was affected quadratically (P = 0.03) by diet; acetate concentration increased linearly (P < 0.01), whereas quadratic effects were observed on propionate concentration (P = 0.03) and acetate-to-propionate ratio (P < 0.01) with increasing dietary SH. Ruminal pH increased linearly (P < 0.01) as corn was replaced by SH. Nitrogen retention was not affected by the addition of SH, in spite of a linear increase in urinary N (P < 0.01). The replacement of corn grain with up to 45% SH (31.4% of SH in the dietary DM) resulted in a trend to decrease apparent digestibility of DM and to increase NDF digestibility, presenting a fermentation pattern that would reduce the risk of acidosis.