Eduardo Castro da Costa

Carcass Traits of Young Red Angus Steers Slaughtered with Different Weights

The carcass quantitative characteristics of feedlot finished Red Angus steers, with initial age of eight months and 189 kg, slaughtered with 340, 370, 400 or 430 kg (SW), were evaluated. The number of days to reach the respective weight was 114, 144, 173 and 213 days. The diet contained 13.13% crude protein, 2.7 Mcal digestible energy/kg DM and a roughage:concentrate ratio of 56:44. Carcass dressing percentage and conformation were not affected by the slaughter weight. The saw cut weight although increasing linearly in weight (91.73; 103.26; 106.20 and 116.66 kg) as the slaughter weight increased, declined linearly when expressed in relation to cold carcass weight. Side cut percentage showed the highest increase (23.36; 25.40; 28.50 and 35%) as the slaughter weight increased, following the increase of subcutaneous fat thickness (3.91; 6.16; 6.16 and 9.58 mm). The Longissimus dorsi muscle (LMA) increased linearly as the slaughter weight increased (LMA = 27.48 + 0.083SW) while the LMA/100 kg of cold carcass weight declined linearly (LMA/100 kg carc. = 45.14 - 0.0425SW). According to the regression equation the minimum subcutaneous fat thickness required by the slaughter weights (3 mm) would be reached at 327 kg of live weight. Considering the minimum carcass weight of 180 kg, it would be reached with the slaughter weight of 337 kg. Using Red Angus breed to produce steers to be slaughtered at young age the slaughter weight should not surpass 400 kg, in order to not exceed the 6 mm of subcutaneous fat thickness, to avoid the carcass trimming for fat excess.

Composição Física da Carcaça, Qualidade da Carne e Conteúdo de Colesterol no Músculo Longissimus dorsi de Novilhos Red Angus Superprecoces, Terminados em Confinamento e Abatidos com Diferentes Pesos

The carcass physical composition, meat quality and cholesterol content in the Longissimus dorsi muscle of 24 Red Angus steers finished in feedlot with different weights were evaluated. Steers average age and weight at the beginning of the feedlot were, respectively, eight months and 189 kg. The number of days on feed was 114, 144, 173 and 213 days to reach the slaughter weight (PA) of 340, 373, 400.6 or 433.6 kg. The carcass composition was affected by the slaugther weight, with a quadratic response for bone percentage (%bone= 92.81 ¾ 0.402PA + 0.0005PA2), being the minimum value of 12% at a PA of 402 kg. The muscle percentage decreased linearly (%musc.= 78.38 ¾ 0.042PA) while the fat percent increased (%fat= 3.92 + 0.052PA). The edible portion:bone ratio showed a quadratic relation with slaughter weight (EP:B= -31.88 + 0.194PA ¾ 0.0002PA2) showing the maximun value of 6.47 for the carcasses produced by animals slaughtered with 395 kg. Muscle:bone ratio did not change with slaughter weight, being the average of 4.4 for all slaughter weights. Meat color and texture were not affected by slaughter weight, while marbling score increased linearly (Marb.= -13.35 + 0.051667PA). Increasing the slaughter weight resulted in lower thawing losses and higher cooking losses. The meat tenderness was not affected by slaughter weight and was classified as tender and very tender. Meat juiciness and palatability were sligthtly above average. The Longissimus dorsi ether extract concentration and cholesterol content were not affected by slaughter weight being 2.35% and 43.07 mg of cholesterol/100 g of muscle, respectively.

Desempenho de Novilhos Red Angus Superprecoces, Confinados e Abatidos com Diferentes Pesos

The feedlot performance of Red Angus steers, with initial age of eight months and 189 kg of initial live weight, fed to reach the slaughter weight (SW) of 340, 370, 400 or 430 kg, was evaluated. The number of days to reach the respective weight was 114, 144, 168 and 209 days, with 12, 13, 14 and 15 months of age. The animals were fed with a 13.13% crude protein diet, and roughage:concentrate ratio of 56:44. The average daily gain was 1.32, 1.27, 1.23 and 1.15 kg, respectively. Dry matter intake (DMI) expressed in kg/day/animal and metabolic weight, did not show significant relation with slaughter weight. When DMI was expressed per 100 kg of live weight a linear decline occurred (DMI/100 kg W= 3.599 - 0.003152SW) as the final weight increased. Body condition improved linearly with the final weight (Body condtion = 0.159 + 0.0103SW), while feed conversion worsen (FCDM = 1.585 + 0.01019SW), however it can be considered satisfactory, being respectively 5.09, 5.35, 5.55 and 6.04 kg of DM/kg of weight gain. In order to reach the minimum carcass weight and subcutaneous fat thickness required, the regression equation estimation showed that slaughter weight should be of 337 and 327 kg, respectively.

Apreciação econômica da terminação em confinamento de novilhos Red Angus superjovens abatidos com diferentes pesos

The objective of this experiment was to conduct an economic evaluation of feedlot finished Red Angus young steers fed to reach slaughter weights (SW) of 340, 370, 400 and 430 kg (actual SW of: 340, 373, 401 and 434 kg). Animals spent 114, 144, 168 and 209 days to reach the target SW at 12, 13, 14 and 15 months of age, respectively. Animals were fed a diet containing 13.26% crude protein and a forage (corn silage) to concentrate ratio of 56:44 (dry matter basis). The most representative operational costs (total costs/ha) for crop establishment and management were: crop fertilization (21.21%), top spreading fertilization (12.86%), seeds (11.40%), and weeds (5.78%) and insect control (4.52%). Feed (forage plus concentrate) represented 77.2% of the production cost when animal acquisition was not included in the calculation with concentrate accounting for 58.3% of these costs. The cost/kg of weight gain increased linearly from 1.94 to 2.34 R

Taxa de prenhez de vacas Nelore x Hereford em ambiente subtropical sob restrição alimentar

/kg when SW was increased from 340 to 434 kg. Increasing SW from 340 to 434 kg reduced the profitability of feedlot finished Red Angus young steers.

Macrominerais para bovinos de corte nas pastagens nativas dos Campos de Cima da Serra - RS

This experiment was conducted to evaluate factors affecting pregnancy rate of 117 crossbred Nelore x Hereford beef cows with age varying from 2 to 20 years, different gene proportion from Nellore breed (25.0, 37.5, 50.0, and 100.0%), calved between 08/11/03 and 12/23/03 and bred by natural service, between 12/10/03 and 03/12/04. The effects of July calving date (JCD), birth weight (BW) and calf sex (S) from previous calving, parity order (PO), hip height (H), weight (WM) and body condition score at the beginning of the mating season (BCS), daily gain during the mating season (DGM), gene proportion from Nellore (GPN) and calf 205-d weight (WW205) from previous calving were all investigated on the probabilities of pregnancy and conception. Data were analyzed by Logistic Regression using SAS to identify the effects of each variable. The average pregnancy rate was 43.2%. The probability of pregnancy and conception were affected by changes on JCD, WM, BCS and DGM. The pregnancy odd changing to each increase on the variable were based on the odds ratio estimative by OR = exp (bk), considering that odd is ratio between the probability of the event occur and not occur. No significant effects of BW, S, PO, H, GFN and WW205 were observed. Pregnancy rate in beef cows can be increased by improving body condition score at the beginning of breeding season and weight gain during the breeding season. Both can be achieved by pre and postpartum nutritional management.

Ganho de peso na recria e desempenho reprodutivo de novilhas acasaladas com sobreano

The present study was conducted to determine the mineral status of natural range pastures of the Campos de Cima da Serra region, State of Rio Grande do Sul, Brazil, in different months of the year, to compare them to beef cattle requirements (NRC, 1996). The project was carried out in twenty private farms, in Cambara do Sul county, on grazing areas without improvements (except burning) in the lastest twenty years. Pasture samples were collected in the several seasons during one year to determine its iron, manganese, copper and zinc levels. Effect of the season was verified on all analyzed minerals. The Mn and Fe contents on grass samples were higher than the beef cattle requirements. However, in some samples Fe and Mn levels were higher than the maximum tolerable for cattle. Cu contents were deficient in some months evaluated and Zn contents were lower than the required for cattle.

Suplementação Energética sobre a Qualidade da Carcaça e da Carne de Vacas de Diferentes Idades, Terminadas em Pastagem Cultivada de Estação Fria sob Pastejo Horário

The objective of this work was to evaluate the effects of growth rate during rearing period, from 13 to 18xa0months, on pregnancy rate of beef heifers mated at yearling during autumn. Treatments consisted of 30 heifers weighing on average 208xa0kg submitted to average growth rate of 0.595xa0kg day-1 (G600), 41 heifers averaging 197xa0kg with average growth rate of 0.656xa0kg day-1 (G700) and 58 heifers with 181xa0kg with average growth rate of 0.723xa0kg day-1 (G800). Treatment effects were determined on body weight, reproductive tract score and pregnancy rate. Pregnancy rate was 30.0% 47.8% and 50.0%, respectively, for G600, G700 and G800, without significant differences among groups. Treatments G700 and G800, with large growth rates, showed higher values of reproductive tract score than G600 at the start of the mating period. Heifers with higher scores had a tendency to present higher pregnancy rates. Pregnancy rates were related to growth rate during postweaning independently of weight variations at mating.

Tendências na comercialização de bezerros relacionadas às características genéticas no Rio Grande do Sul

The objective of this experiment was to study different levels of energy supplementation on the carcass and meat qualitative characteristics of beef cull cows of different ages, under temporary grazing on cultivated pasture of ryegrass (Lolium multiflorum) plus triticale (X triticosecale). Fourty Charolais cows were divided into four age classes: four, five or six, seven or eight and nine or more years, and randomly alloted to four levels of supplementation (SL): 0, .3, .6 and .9% of live weight. The supplement used was grounded sorghum grain. No significant interaction was observed between supplementation level and cow age. SL did not affect meat color, texture and marbling, neither carcass physical composition, meat sensorial characteristics and thawing and cooking losses. With age increasing, decreased the muscle percentage, being 68.5, 66.7, 65.1 and 64.3%, respectively. Young cows showed lower fat percentage (14.4%) than the older animals, that showed 17.9, 19.2 and 18.7%, respectively, for five or six, seven or eigth, and nine or more years of age. Young cows showed lower muscle + fat / bone relation than the animals slaughtered with intermediate age. Cows slaughtered at four years showed more tender meat (5.92 points) than cows slaughtered at seven or eigth (4.69 points) years of age.

Taxas de prenhez em novilhas de corte acasaladas aos 18 e 24 meses de idade

Este trabalho foi realizado com o objetivo de caracterizar os efeitos dos aspectos dependentes da genetica de bezerros comercializados no estado do Rio Grande do Sul e verificar sua influencia no preco de venda. Foram coletados em 13 feiras municipais de bezerros de corte no estado dados referentes ao grupo genetico predominante, ao tamanho e a musculatura dos animais de 739 lotes, correspondendo a 11.986 cabecas. Foram avaliados o preco obtido por kg de peso vivo, a porcentagem de liquidez e a valorizacao do bezerro durante a comercializacao. A frequencia de bezerros sem predominância genetica ainda e grande nas feiras do estado, no entanto, esses animais tem menor preferencia do comprador, pois tem menor liquidez em relacao ao outros grupos ofertados. Os bezerros do grupo genetico sintetico (Braford, Brangus ou Canchim) sao comercializados com maiores precos por kg de peso vivo e sao mais valorizados. Para caracteristicas de tamanho e desenvolvimento muscular, os bezerros grandes e fortes tiveram maior liquidez em comparacao aos de estrutura media ou pequena, portanto, tem maior preco e valorizacao por kg de peso vivo.