Flávio Dutra de Resende

Composição físico-química e produção do leite de búfalas da raça Mediterrâneo no oeste do Estado de São Paulo

The objective of this study was to evaluate milk yield and some physico-chemical characteristics of milk from Mediterranean buffalo cows raised in western Sao Paulo. A total of 1438 observations was collected from 152 lactations that occurred from 1985 to 1995, at the Experimental Station of Andradina. The data were analyzed by means of the GLM procedure of SAS. The statistical model for milk production had month and lactation as fixed effects. The model for chemical constituents included milk yield as covariate. All effects were significant. The overall adjusted means were 4.52 kg, 4.13%, 6.59%; 17.01%, 10.47% and 18.98°D for milk production, protein, fat and total solids, solids not fat and titratable acidity, respectively. High nutrient contents were observed, which shows the good quality of the product.

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.

Mastite subclínica causada por Staphylococcus aureus: custo-benefício da antibioticoterapia de vacas em lactação

Economic evaluation of the treatment bovine subclinical mastitis caused by S. aureus was evaluated. Two hundred and seventy udder quarters with or without subclinical mastitis were distributed into four groups, in conformity to lactational stage and treatments. Group 1 included animals treated between 10 and 60 days of lactation; group 2 included animals treated from 61 days of lactation to two months before drying; group 3 included animals no treated between 10 and 60 days of lactation; group 4 included animals no treated from 61 days of lactation to two months before drying. Treatment with gentamicin (150mg) was accomplished by intramammary doses, once a day, after performing sensitivity tests. The mammary quarters were re-evaluated after 30 days. The costs with the treatment were calculated considering a S. aureus prevalence of 5% as well as expenses with antibiotic, milk disposal, tests of drug sensitivity and workload. There was loss of income of 2% and 14% in the groups 1 and 2, respectively, when compared with the values before the treatment. In such case, the treatment of bovine subclinical mastitis caused by S. aureus in the lactation was economically unviable.

Digestão total e parcial de alguns componentes de dietas contendo diferentes níveis de casca de soja e Fontes de nitrogênio, em bovinos

This experiment was conducted to evaluate the effect of two levels of soybean hulls and three sources of protein on the total and partial rumen and intestinal digestion. Six Holstein-Zebu steers averaging twelve months of age and 229 kg BW were fistulated in the rumen and in the abomasum and distributed in a 6x6 Latin square and fed ad libitum individually. The consumption and the total and partial digestibility of the nutrients were evaluated. There was no effect of the source of protein on consumption, amounts of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) in the rumen, abomasum and in the faeces and on the digestibility coefficients of these components. On the other hand, increasing the levels of soybean hulls significantly increased the coefficients of digestibility in the whole digestive tract. However, the levels of soybean hulls did not affect the digestion of CP, NDF and ADF in the intestines. The results indicate that soybean hulls can replace maize, due their degradation similarity, and can partially replace the roughage in rations for ruminants, by having high levels of fiber with great potential and speed of ruminal fermentation. Poultry by-product meal and starea can replace soybean meal without negative effects on the digestion of their nutritive components.

Bovinos mestiços alimentados com diferentes proporções de volumoso:concentrado. 1. Digestibilidade aparente dos nutrientes, ganho de peso e conversão alimentar

The objective of this work was to evaluate the effects of the forage to concentrate ratio on the weight gain and feed: gain, and to determine the apparent digestibility of the nutrients of 25 and 20 crossbred steers averaging 310 kg LW, respectively. Five full fed diets based on tanzaniagrass hay and concentrate, with different forage to concentrate ratio (85:15, 70:30, 55:45; 40:60; and 25:75) were used. The regression analysis of the coefficienties of apparent digestible dry matter, digestible organic matter, neutral detergent fiber, digestible protein and gross energy in function of the concentrate level in the diets presented quadratic effect and the maximum estimated coefficienties were 67.0, 70.0, 51.0 42.0 74.0 and 69.0 %, for the levels of 54, 58, 28, 12, 34 e 77 % of concentrate in the diets, respectively. The average daily gain (ADG) linearly increased with the increase of the concentrate level in the diets. There was an increase of 0.00895 kg/day in the ADG for each percent increase on the concentrate level in the diets, from 15.0 to 75.0 %. In the same range, the feed: gain of DM, CP, and GE increased 0.08; 0.011468; and 0,50646, respectively, for each percent increase on the concentrate level in the diets. The maximum nutrient digestion for the maximum efficiency of nutrient utilization occurred with the intake of neutral detergent fiber ranged from 1.25 to 1.02% LW for crossbred steers

Immunocastration improves carcass traits and beef color attributes in Nellore and Nellore×Aberdeen Angus crossbred animals finished in feedlot.

The objective was to examine the effects of immunocastration on carcass traits and meat quality of Nellore and Nellore×Aberdeen Angus male animals finished in feedlot. Surgically castrated, immunocastrated, and intact animals were finished in feedlot for 90 days. The animals were harvested, and carcass traits were evaluated. Carcasses were chilled, and one 2.5-cm steak was fabricated from Longissimus thoracis muscle. The steaks were individually vacuum packaged and frozen at -18 °C. Frozen steaks were thawed, and pH, instrumental color, cooking loss, and shear force were determined. Immunocastrated animals demonstrated greater (P<0.05) hot dressing percentage and cold dressing percentage than their surgically castrated counterparts. Furthermore, steaks from immunocastrated and surgically castrated animals exhibited greater redness (P<0.05) and lower darkness (P<0.05) than steaks from intact animals, indicating possible advantage in retailing. The results suggested that immunocastration may be utilized to improve carcass traits and beef color in feedlot-finished Nellore and Nellore×Aberdeen Angus males.

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.

Dinâmica fermentativa e microbiológica de silagens dos capins tanzânia e marandu acrescidas de polpa cítrica peletizada

The experiment was carried out to evaluate the fermentative and microbiological dynamics of the tropical grass silages using pelleted citrus pulp (PCP) as an additive. The Tanzania (Panicum maximum cv. Tanzania) and Marandu (Brachiaria brizantha (Hochst. ex. A. RICH) Stapf cv. Marandu) grasses were harvested at 64 and 49 days of regrowth, respectively. The following treatments were evaluated: control (0%), addition of 5% and 10% of pelleted citrus pulp (PCP) in a fresh matter basis, and seven fermentation periods (1, 4, 7, 14, 21, 28, and 56 days) after the ensilage. Experimental PVC silos with Bunsen valve to eliminate gas were used. The forage was compacted to obtain 550 kg/m3 of bulk density. It was used a split-plot arrangement in a complete randomized experimental design, with three replications per treatment. The addition of PCP increased the DM concentration and reduced the pH values of the silages. The concentration of NH3-N (total N) was affected by the PCP addition, and the absence of PCP resulted in silages with high N-ammonia concentration, which characterizes silages with questionable quality. The addition of PCP increased the molar concentration of the acetic and propionic acids. The enterobacteria population was detected only in the first day in the tanzaniagrass silage, and until the tenth eighth day of fermentation on the marandugrass silage. The homofermentative bacteria population was similar to the heterofermentative on the evaluated silages.

Application of the first canonical variable in the evaluation of animal production trials

The objective of this work was to evaluate the inter treatment discrimination according to feed conversion efficiency in several animal performance experiments. The variables investigated were: feed conversion ratio (FCR = intake: production ratio), feed efficiency index (FEI = production: intake ratio) and bio-nutritional index (BNI). The BNI was constructed from the first canonical variable obtained based on the multivariate analysis of variance of the intake and animal production (weight gain or milk production) variables. The results indicated that FCR and FEI reciprocated each other at experimental plot level but did not reciprocate at animal group or treatment level. This fact implicates distortions on the descriptive levels of probability of type I error for hypotheses tests and compromises the statistical and animal production inferences. On the other hand, the BNI index guarantees the maximum discrimination among experimental groups and allows to identify significant differences, which were not observe with FCR or FEI indexes. This fact can be associated to the incorporation of animal production intensity characteristics using BNI.