Luiz Angelo Damian Pizzuti

Composição física da carcaça e qualidade da carne de novilhos Charolês e Nelore que receberam diferentes proporções de concentrado na dieta

Avaliaram-se a composicao fisica da carcaca e a qualidade da carne de 22 novilhos contemporâneos, com media de idade de 22 meses, das racas Charoles ou Nelore, terminados em confinamento, e que receberam diferentes proporcoes de concentrado na dieta. A fracao volumosa da dieta foi composta pelas silagens de milho e sorgo em partes iguais. Os animais foram distribuidos em tres tratamentos constituidos por 35, 50 ou 65% de concentrado na materia seca. Nao houve efeito (P>0,05) da porcentagem de concentrado na dieta sobre a composicao fisica da carcaca. A proporcao de inclusao do concentrado influenciou (P=0,0013) positivamente a maciez da carne, aumentando em 0,026 pontos a cada ponto percentual de aumento do concentrado. As demais caracteristicas qualitativas da carne nao foram influenciadas (P>0,05) pelo aumento do concentrado na dieta. A carne dos novilhos Charoles apresentou textura mais fina, 4,15 x 3,14 pontos, foi mais macia, 6,85 x 5,71 pontos, mais suculenta, 7,17 x 5,77 pontos, e apresentou menor resistencia das fibras ao cisalhamento, 3,79 x 5,79kgF. A carcaca dos novilhos Charoles apresentou maior deposicao muscular, 65,5 x 61,5%, e a dos novilhos Nelore apresentou maior percentagem de gordura, 23,3 x 20,3%.

Frequências do fornecimento do alimento no desempenho de vacas e novilhas em confinamento

The effect of frequency of supply of forage (V) and concentrate (C) on the performance of cows and heifers in feedlot was studied. The treatments were the following frequencies in the supply: 2 V/C= V and C twice daily; 1 V/C= V and C once daily; 1 V/2C= once V and C twice daily, 1 V/3C= once V and C three times a day, for the cows or heifers. The experimental design was completely randomized in factorial arrangement 4 x 2, with four replications. There was no significant interaction between frequency of supplying and category animal. The dry matter intake (DMI) was superior for the animals fed 1 V/2C or 1 V/3C a day in relation with the supply of 2 V/C and 1 V/C, presenting values of 11.7; 11.4; 10.6 and 10.7 kg, respectively. The average daily gain (ADG) was not influenced by the frequency of supplying. The DMI was higher in cows (12.6 kg) than heifers (9.57 kg), having no difference in the weight gain. Increasing frequency of feeding the concentrate to two or three times a day, provided greater consumption, not influencing the weight gain of cows and heifers confined.

Performance of finishing steers fed different sources of carbohydrates

The objective of this study was to evaluate the effect of carbohydrate sources (corn, soybean hulls or wheat bran) in the diet on performance of feedlot steers in the finishing phase. Twenty-four Charolais × Nellore crossbred steers, aged 22 months and initial weight of 335.0±10.9 kg were used in the experiment. Diets contained 40% sorghum silage and 60% concentrate. The intakes of dry matter (DM; 10.68, 10.16 and 10.34 kg/day) and crude protein (1.66, 1.70 and 1.72 kg/day) were not affected by diets with corn, soybean hulls or wheat bran, respectively. The intakes of neutral and acid detergent fiber were higher for soybean hulls, but the diet containing corn provided higher intake of non-fibrous carbohydrates, total digestible nutrients and digestible energy. Weight gain was higher and better feed conversion for animals fed corn (1.57 kg/day, 6.85 kg DM/kg gain) or soybean hulls (1.58 kg/day and 6.61 kg DM/kg gain) compared with steers receiving wheat bran (1.29 kg/day and 8.14 kg DM/kg gain) in the diet. There was no significant effect of carbohydrate sources on the final body score (3.78 points), energy conversion (28.25 Mcal digestible energy/kg gain), hot carcass yield (57.63 kg/100 kg BW) and fat thickness (3.1 mm). From an economic point of view, soybean hulls can be an alternative source of carbohydrate to corn in diets of finishing steers with 60% concentrate.

Development and reproductive performance of beef heifers supplemented with brown rice meal and/or protected fat on temperate grasslands

The response of energy supplementation was evaluated on the development and reproductive performance of beef heifers on temperate grasslands. Twenty-eight Charolais × Nellore heifers, with initial average age of 18 months and initial live weight of 274.9 kg were utilized. The animals were maintained on oat + ryegrass pasture and distributed in the following treatments: no supplementation (NS): heifers kept exclusively on pasture; MEG: supplementation with protected fat Megalac®; BRM: supplementation with brown rice meal; BRM+MEG: supplementation with BRM + protected fat. The average final weight of the heifers was of 403.4 kg and corresponded to 89.5% of the adult weight. The body condition of heifers increased linearly with daily increase of 0.012 points, correlating positively with the final weight. There was interaction between treatment and period for average daily weight gain. The highest daily weight gain, 1.395 kg, occurred in the first period when the animals were supplemented with BRM+MEG. In the last period, the NS animals presented the lowest daily weight gain, 0.888 kg. Supplementation with brown rice meal and/or protected fat does not interfere in the intake of pasture by heifers or increase the total intake of dry matter, not changing, therefore, the average daily weight gain at the end of the period of grazing. The daily weight gain does not change during supplementation. The use of temperate pasture with and without supplementation promotes the proper development of the structure and reproductive tract of heifers, benefiting the animal performance indexes in the first mating at 25-27 months of age.

Production parameters and forage loss of oat and rye grass pastures managed with beef heifers fed diets with energy supplementation

Production parameters of intercropped pastures of oat and rye grass managed with beef heifers supplemented with brown rice meal and/or protected fat were evaluated. Twenty-eight Charolais × Nellore crossbred heifers at initial average age of 18 months and initial average live weight of 274.9 kg were utilized in the experiment. Animals were kept on oat + rye grass pastures and distributed in the following treatments: no-supplementation (NS): heifers kept only in pastures; Megalac (MEG): supplementation with protected fat; brown rice meal (BRM): supplementation with BRM; BRM + MEG: supplementation with BRM plus protected fat. The greater participation of oat leaf was from July 5th to August 10th, 2009 and of rye grass, from August 30th to September 26th, 2009. The crude protein content increased until the 55th day (225.1 g/kg). Pasture total digestible nutrients presented a cubic behavior, with an average of 722.0 g/kg. The highest supply of leaf blades, 5.17 kg of dry matter/100 kg of live weight, was found in the second period. Pasture intake increased throughout the periods. Forage mass and support capacity of the animal did not differ between treatments, presenting means of 1245.02 kg of dry matter/ha and 882 kg of live weight/ha, respectively. Stoking rate, forage loss and pasture intake were not affected by the treatments. Supplementation of beef heifers with rice meal and/or protected fat did not change production parameters of oat + rye grass pastures or pasture intake. Increase in daily accumulation rate of dry matter and supporting capacity of the animals increases forage losses.

Qualitative characteristics of meat from cull cows of different genotypes and age class slaughter under different finishing systems: a meta-analytic approach

The aim of this study was to evaluate, by meta-analysis, the quality of the meat of the cows according to genotype, termination system and age class slaughter. During an online research were identified 15 articles with information related to meat quality of slaughtered cows. The data were grouped according of the genotype of cows being: zebu or continental defined, crossed zebu x british or zebu x continental; according to termination system: feedlot or grassland; according to age of slaughter, where: up to 4 years old (young), 4-8 years old (adult) or more than 8 years old (old). The meat of the continental crossbred cows was softer than the other genotypes, both panel of evaluators and by Shear. The meat of cows finished in feedlot showed higher marbling degree in relation to meat of females finished on grassland. The reduction of the slaughter age of cows improved the meat color. The cows genotype affects the organoleptic aspects of meat while the finished system and slaughter age affects the sensory aspects of meat.

Behavior pattern of beef heifers supplemented with different energy sources on oat and ryegrass pasture

The objective of this study was to evaluate behavior patterns of heifers grazing on black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.), fed supplementation with brown rice meal and/or protected fat. A total of 28 Charolais × Nellore crossbred heifers at average initial age of 18 months and with initial live weight of 274.9±4.97 kg were used in the experiment. Animals were kept in oat + ryegrass pastures and distributed in the following treatments: no supplementation; Megalac (MEG): protected fat supplementation; supplementation with brown rice meal (BRM); and supplementation with BRM + MEG. The neutral detergent fiber (NDF) intake of pasture either in kg or in percentage of live weight was not changed by supply of supplement, but increased linearly (0.045 kg per day) over grazing periods. Supplementation with BRM and BRM + MEG reduced grazing time, 49.63%, in relation to non-supplemented animals and animals supplemented with MEG, 63.13%. Feeding seasons per minute increased over the experimental period with reduction in time spent in each feeding station. The number of bites per feeding station decreased linearly, with a variation of 34.48% in the late grazing period. Heifers supplemented with BRM and BRM + MEG require less time for grazing and increase their idle time, with no modification in displacement patterns within the paddocks and pasture ingestion. Grazing and idle time does not change in the distinct periods of pasture use, but rumination time increases with days of pasture use and with increase in NDF intake.