Guilherme Fernando Alleoni

Efeitos da seleção para peso pós-desmame sobre características de carcaça e rendimento de cortes cárneos comerciais de bovinos

Data from 44 bulls of the genetic groups Selection Nellore (NeS), Control Nellore (NeC) and Caracu (Ca) herds born in 1999 were used to evaluate the effects of selection for post weaning weight on carcass traits and meat cuts yields at 378 days of age (P 378). The animals were randomly distributed into two experimental classes: restricted feeding (AR) and ad libitum feeding (AL) including 8 animals from the NeS and Ca groups and 6 animals from the NeC group. Animals of each class were slaughtered in pairs when the animals AL group reached 4 mm of ultrasonic fat thickness on Longissimus dorsi muscle, between the 12th and 13th ribs. The interaction between genetic group and feeding class was not significant for most of the traits evaluated. The genetic group effect was significant. Animals of the Ca and NeS groups were heavier at slaughter and Ca animals required longer feedlot period to reach the desired fat thickness. Higher slaughter weights of these animals changed their carcass, hindquarter, forequarter and spare ribs weights. The selection for P 378 in the Nellore group resulted in heavier weights at slaughter, heavier carcasses and primary cuts, but lower meat tenderness, although within reasonable values of shear force (below 5.0 kgf).

Evaluation of carcass characteristics of Bos indicus and tropically adapted Bos taurus breeds selected for postweaning weight

Data from 9 studies were compiled to evaluate the effects of 20 yr of selection for postweaning weight (PWW) on carcass characteristics and meat quality in experimental herds of control Nellore (NeC) and selected Nellore (NeS), Caracu (CaS), Guzerah (GuS), and Gir (GiS) breeds. These studies were conducted with animals from a genetic selection program at the Experimental Station of Sertãozinho, São Paulo State, Brazil. After the performance test (168 d postweaning), bulls (n = 490) from the calf crops born between 1992 and 2000 were finished and slaughtered to evaluate carcass traits and meat quality. Treatments were different across studies. A meta-analysis was conducted with a random coefficients model in which herd was considered a fixed effect and treatments within year and year were considered as random effects. Either calculated maturity degree or initial BW was used interchangeably as the covariate, and least squares means were used in the multiple-comparison analysis. The CaS and NeS had heavier (P = 0.002) carcasses than the NeC and GiS; GuS were intermediate. The CaS had the longest carcass (P < 0.001) and heaviest spare ribs (P < 0.001), striploin (P < 0.001), and beef plate (P = 0.013). Although the body, carcass, and quarter weights of NeS were similar to those of CaS, NeS had more edible meat in the leg region than did CaS bulls. Selection for PWW increased rib-eye area in Nellore bulls. Selected Caracu had the lowest (most favorable) shear force values compared with the NeS (P = 0.003), NeC (P = 0.005), GuS (P = 0.003), and GiS (P = 0.008). Selection for PWW increased body, carcass, and meat retail weights in the Nellore without altering dressing percentage and body fat percentage.

Estimation of carcass and empty body composition of zebu bulls using the composition of rib cuts

Determination of body composition is very important in nutritional and growth regulation studies. However, determination of body composition by grinding and analyzing all tissues is unfeasible as an experimental routine. The objective of this study was to test methodologies for body composition estimation. Linear measurements and chemical composition of the 9-10-11th and 10th rib sections were used to estimate chemical composition of 31 Nellore (Zebu) intact males with an average 333.5 kg body weight (range of 180.5 to 496.0) and 16.1% empty body lipid (range of 10.6 to 22.1). Composition of ribs, carcass and empty body were obtained by quantitatively grinding, homogenizing and sampling all body tissues. The 9-10-11th composition was a good estimator of body composition with r2 of 0.99; 0.98; 0.98 and 0.91 for estimates of kg water, lipid, protein, and ash; with low standard errors of the estimate. Results with the 10th rib cut were similar (r2 of 0.98, 0.98, 0.97 and 0.88 for the same regressions). Data are in the range of published results, however coefficients of regression were statistically different from those published for Bos taurus populations. Rib cut composition is a good parameter for the estimation of chemical body composition, but specific equations must be used for Zebu animals.

Características de carcaça de bovinos de diferentes grupos genéticos, castrados e não-castrados, em fase de terminação

The objective of this trial was to investigate the physical characteristics of carcasses and primary cuts of 86 steers and bulls averaging 329 kg of body weight and 20 months of age. Twelve Gir, 20 Nellore, 20 Guzera , and 20 Caracu all from herds that genetically selected for weight gain at 378 days of age and 14 non-genetically improved Nellore (control) were used in this study. Corn silage was used as the forage portion of the diet in a 60:40 (% DM) forage to concentrate ratio. A completely randomized design with a 5 x 2 factorial arrangement of treatments (genetic group and sexual condition) was used. Bulls had carcasses with greater weight, yield, and proportion of muscular tissue but similar subcutaneous fat thickness compared to steers. Caracu showed a slower development but greater muscular tissue deposition and less fat deposition resulting in higher proportion of beef round compared to the remaining breeds. The genetically improved Zebu had heavier carcasses than the non-genetically improved Nellore. The greatest hot carcass weight within Zebu was observed on the genetically improved Nellore (287 kg) and was similar to that found on Caracu (299 kg). Genetically and non-genetically improved Nellore and Gir had the highest yields of hot carcass (57.83, 56.82 and 57.26%, respectively). Caracu showed the greatest carcass length (134 cm) while non-geneticallyimproved Nellore the lowest (118.67 cm). The rib eye area was greater on Caracu than Zebu whereas the opposite was observed for subcutaneous fat thickness with the exception of Gir. Within the genetically improved animals, Nellore had the greatest carcass weight and within sexual condition, bulls showed finishing covering fat that fulfills the market requirements.

Estimativa da composição química corporal de tourinhos Santa Gertrudes a partir da composição química e física das 9-10-11ª costelas

Simple linear regressions to estimate empty body chemical composition of Santa Gertrudis young bulls were obtained, using the physical and chemical composition of the 9-10-11th ribs cut. Fifteen intact males, from nine to fifteen months of age and from 220 to 505 kg of liveweight, were kept confined. They were slaughtered after 18 hours without water and food, and six of them were slaughtered after adaptation period. The content of water, protein, lipid and ash were determined on the ribs cut and on the blood, hide, head + feet, visceras and carcass, and samples were obtained after quantitatively grinding and homogenizing the entire tissue. The physical composition of the ribs was determined by manual separation of bone, lean and fat. Empty body weight was closely related to hot carcass weight (r² = 0.99). Percent water and lipid of the 9-10-11th ribs cut were closely related to the empty body chemical composition, but not to the percent protein and ash, that can be calculated from their proportions on the empty body without fat. The physical composition of the ribs cut was a good estimator of the empty body composition, mainly for the equations using separable ribs fat to estimate the contents of water, ether extract and ash, but not protein content. Despite the good results with the ribs cut physical composition, chemical composition was a more efficient estimator of empty body chemical composition, because the coefficients of determination were higher and the standard errors were lower. As the percentage of water in empty body was closely related to the water percent on 9-10-11th ribs (r² = 0.95) and the percentages of ether extract and water in the empty body (r² = 0.94) were closely related each other, the water in the 9-10-11th ribs cut alone can be used to estimate empty body composition.

Avaliação da silagem de grãos de milho úmido com diferentes volumosos para tourinhos em terminação: desempenho e características de carcaça

O experimento foi realizado com o objetivo de comparar os efeitos do fornecimento de silagem de graos de milho umido com o milho em grao seco, associados a silagem de milho ou ao bagaco in natura de cana-de-acucar, sobre o desempenho e as caracteristicas da carcaca de bovinos em terminacao. Em blocos ao acaso e esquema fatorial 2 × 2, 28 tourinhos Santa Gertrudes (dez meses de idade e peso corporal inicial de 245 kg) foram mantidos em confinamento durante 142 dias. Os animais foram mantidos em baias individuais e receberam dietas com 12 e 20% da MS em forma de bagaco ou silagem, respectivamente. O milho umido foi moido e ensilado quando se encontrava com 30% de umidade. Nao houve interacao significativa tipo de volumoso x tipo de processamento do milho sobre as variaveis estudadas. O bagaco mostrou-se viavel como fonte exclusiva de fibra, apesar de os resultados de ganho de peso, eficiencia alimentar, peso e rendimento de carcaca e espessura de gordura subcutânea terem sido inferiores aos obtidos com a silagem de milho. O ganho diario de peso nos animais alimentados com o bagaco foi em torno de 1,3 kg, enquanto, com a silagem, foi de 1,5 kg. O consumo de MS nao foi influenciado pelo tipo de volumoso ou pelo processamento do milho. O uso da silagem de graos de milho umido melhorou a eficiencia alimentar em 9,7% e reduziu o peso do figado quando comparado ao milho seco, mas nao alterou as demais caracteristicas avaliadas.

Composição corporal e exigências líquidas de proteína e energia de bovinos de quatro grupos genéticos terminados em confinamento

The body composition and protein and energy requirements for growth of steers of four genetic groups finished in feedlot were evaluated in this experiment. comparative slaughter method was used in a completely randomly experimental design, with four treatments: Nellore (NE), ½ Aberdeen Angus + ½ Nellore (AN), ½ Canchim + ½ Nellore (CN) e ½ Simmental + ½ Nellore (SN). Forty-seven steers averaging 310 kg initial shrunk body weight (SBW) and 22 months were fed during 101 days in a feedlot. Diet on feedlot had the following composition: crude protein, 13.34%; rumen degradable protein, 9.35%; and total digestible nutrients, 71.81% (estimated value). Composition of the 9th-10th-11th ribs was used to calculate empty body composition. No significant differences were found between AN (428 kg) and SN (410 kg) in final empty body weight (EBW), and similarly among CN, NE and SN (389, 390 and 410 kg, respectively), but EBW of AN steers was greater than that of CN and NE cattle. AN steers had higher amount of fat percentage on rib cut. However, less proportion of muscle was observed in the AN group and less bone percentage at the rib cut of the Nelore breed. AN and SN groups had the largest concentration of ether extract and the smallest amount of water percentage on the empty body at slaughter. Steers of AN, NE and SN groups were similar in rate of energy deposition (6.06, 5.20 and 5.80 Mcal/day, respectively). There was no difference among AN and CN cattle on ether extract in empty body weight gain. Simmental × Nelore demonstrated the greatest requirements of protein (0.164 kg/kg of EWG), and AN and CN cattle (0.140 and 0.142 kg/kg of EWG, respectively), the smallest. Angus × Nelore animals required the greatest net energy for gain (4.685 Mcal/kg of EWG).

Exigências líquidas de proteína e energia para ganho de peso de tourinhos Brangus e Nelore alimentados com dietas contendo diferentes proporções de concentrado

The energy and protein requirements for gain of Brangus and Nellore bulls were estimated using the comparative slaughter technique, in which the empty body as well as the gain composition were estimated through the 9th -10th -11th rib cut. Twenty-eight animals from each breed were used in this research. At the beginning of the trial four animals from each breed were slaughtered to determine the initial body composition while the remaining bulls had free access to diets containing 20, 40, 60 or 80% of concentrate (dry matter basis) during 145 days. The average initial and final shrunk body weights were 238 and 402 kg for Brangus and 230.7 and 361.9 kg for Nellore, respectively. Animals averaged eight months of age in the beginning of the trial. The final average shrunk body gain, empty body gain, and hot carcass gain differed between breeds and concentrate levels with greater values found for Brangus and 60% of dietary concentrate, respectively. Fat and energy contents in the empty body were greater for Brangus while water, protein, and ash were higher for Nellore bulls. Protein and energy requirements for empty weight gain differed between breeds averaging 0.161 and 0.188 kg of protein and 3.02 and 2.46 Mcal of energy per kg of empty weight gain for Brangus and Nellore, respectively. Although it was observed greater energy requirement for Brangus and greater protein requirement for Nellore, no effect of concentrate level was found probably because the age of the bulls prevented animals to reach a stage of greater fat deposition.

Validação dos sistemas VIÇOSA, CNCPS e NRC para formulação de dietas para bovinos Nelore e Caracu, não-castrados, selecionados em condições brasileiras

Twenty-two animals, eight from genetic improved Nellore breed, six non-improved Nellore and eight from genetic improved Caracu breed, were used to evaluate and to validate the VICOSA, CNCPS (level 1 and 2) and NRC (level 1 and 2) systems, for diet formulations. The animals were confined with average live weight of 404 kg to genetic improved Nellore, 345 kg to non-improved Nellore and 434 kg to genetic improved Caracu breed, all with 18 months of age. The forage used was corn silage in forage to concentrate ratio of 50:50 in the diet. The slaughter criterion was determined by ultra-sound and it was executed when the animals reached an average of four millimeters of subcutaneous fat. The Student t test was used to compare the dry matter intake (DMI) and average daily gain (ADG) observed in the genetic groups and those predicted by the VICOSA, CNCPS and NRC systems. The VICOSA system showed a good estimate for ADG of the animals of genetic improved Nellore and non-improved Nellore breed, but the values were different of observed to improved Caracu. The VICOSA system does not have a good estimate for DMI for none of the three genetic groups. The CNCPS system, level 1 and 2 was efficient to estimate the DMI of the three genetic groups; however the estimative for ADG differed from the observed for both level 1 and level 2 of the system and the values were underestimated. In the NRC system, only the level 2 showed predicted values similar to those observed for both DMI and ADG.

Desempenho e características da carcaça de tourinhos Santa Gertrudes confinados, recebendo dietas com alto concentrado e níveis crescentes de polpa cítrica peletizada

The experiment was developed to evaluate the effect of the replacement of corn grain by dehydrated citrus pulp pellets on the performance and carcass characteristics of Santa Gertrudis young bulls fed high concentrate diets. Twenty-eight bulls, with average age of nine months and an initial weight of 277 kg, were kept in individual pens and fed during 92 days, after 21 days of adaptation. The animals were fed a diet with 20% of the dry matter as corn silage, with 40% of grain. Treatments evaluated included levels of 0, 25, 40 and 55% of dehydrated citrus pulp pellets in the dry matter diet. There was no effect of citrus pulp level on the average daily gain, daily dry matter intake, feed efficiency, carcass dressing, Longissimus muscle area and the kidney, pelvic and inguinal fat. The increasing level of citrus pulp on the diet decreased linearly the backfat thickness and increased linearly the liver weight and carcass weight. The feces pH was similar for all the citrus pulp levels. Liver abscess were not detected, although the diet had high concentrate level. The dehydrated citrus pulp pellets can compound until 55% of dry matter diet, replacing corn grain to finishing young bulls fed high concentrate diets, with a small decrease in subcutaneous fat.