ABSTRACT Two hundred seventeen grass-finished Braford steers were assessed by ultrasonic scanning and subsequently harvested with their pistol hindquarters fabricated into boneless wholesale cuts. The Longissimus thoracis muscle area and subcutaneous fat depths were measured. The objectives of this study were: 1) to develop prediction equations for weights of the pistol hindquarter and high-value commercial cuts, and 2) to estimate sample size needed for experiments comparing pistol hindquarter retail product weight using either physically or ultrasonically measured carcass traits. Carcass measurements explained 44 % to 94 % of the variation in weights of individual cuts, whereas, measurements that were made using ultrasound explained 42 % to 90 % of the variation in the weights. Models used to predict the weight of pistol hindquarter retail product with carcass measures and ultrasound measures showed high coefficient of determination (R 2 = 0.92 and 0.97, respectively). Whether based on carcass or ultrasound measures, models used to estimate weight percentage of fat trimmed from the pistol hindquarter had lack of fit. In general, models for individual cuts weights that used traits measured with ultrasound as independent variables approached the accuracy of models using carcass traits. Thus, only slightly greater samples sizes were required to have equivalent power to detect differences in retail product weights using ultrasound measures. For experiments of equivalent power, differences in the number of animals required may be offset by avoiding costs for slaughter and fabrication.

ABSTRACT This study was intended to evaluate body size structure and growth parameters of crossbred heifers fed at four nutritional levels to achieve puberty earlier. Animals were classified depending on their level of crossing between Nelore and Hereford and subjected to four nutritional levels (kg day−1) as follows: 0.5 (light; n = 32), 0.75 (medium; n = 32), 1.00 (high; n = 29), and 1.25 (very high; n = 27). Heifers at puberty and at weaning were individually classified for growth parameters. The fat thickness and longissimus muscle area throughout the experimental period were determined by ultrasonography. The height, heart girth, frame, and weight:height ratio were variables used to evaluate body traits. Univariate analysis of variance using the GLIM MIXED procedure os SPSS was performed and the significance level was set at 0.05. Age and body weight at puberty were 388±1.9 days and 331.4±1.3 kg, respectively. Body condition score demonstrated an interaction between nutritional level and crossbred degree. Heifers with the highest degree of Nelore had higher fat thickness and lower weight:height ratio compared with other racial groups at puberty. Pearson correlation coefficient showed a negative association for body condition score (−0.34) and fat thickness (−0.58) compared with age at puberty. The increased fat thickness at younger ages at puberty was observed in all racial groups. The increased weight:height ratio at younger ages at puberty was observed in all racial groups. We observed higher values for a frame in animals at the higher level of supplementation. There is a greater correlation between live weight gain and phenotypic traits during weaning to achieve puberty at an earlier age in crossbred heifers.

ABSTRACT Aiming at breeding heifers with 14-15 months of age, 100 Hereford calves were subjected to different feeding systems. Heifers grazed on a natural pasture in early winter, fed or not a supplement (14% crude protein; 72% total digestible nutrients), were transferred to a ryegrass pasture for 73 days, and then returned to a natural pasture for 15 days until the beginning of the breeding season. During the last 15 days on ryegrass pasture and the 15 days of the return to the natural pasture, half of the heifers of the two previous systems were offered the supplement, thereby establishing four feeding treatments. Heifers supplemented during the second period, independently of supplementation during the first grazing period, presented higher average daily gain and greater backfat values than the non-supplemented heifers. The breeding season extended for 75 days. At the start of the breeding season (November 18), heifers supplemented during both periods presented higher body condition score and body weight. The highest percentage of puberty was determined in heifers supplemented in the early winter. Heifers supplemented during both periods presented the highest pregnancy rate. Pregnant heifers presented higher average daily gain when fed the supplement during the second period, as well as higher relative pelvic area, body weight, and body condition score at the start and end of the breeding season. To an expressive pregnancy in 14- to 15- month-old heifers, higher weaning weights and pasture allowance are required to get a better answer to supplements offered.

The objective of this study was to develop equations to predict retail product and fat trim (weights and percentages) for Nellore (Bos indicus) cattle. Live ultrasound measurements of the longissimus muscle area, backfat thickness at the 12th rib and rump fat depth and shrunk body weight were obtained from 218 Nellore steers to predict weights and percentages of carcass retail product, pistola retail product and fat trimmings. After slaughter, carcasses were deboned and weighed and percentages of retail cuts were obtained directly. Measurements taken directly in the carcasses explained 97% and 36% of variation in carcass retail product weight and percentage, and 94% and 36% of variation in pistola retail weight and percentage, respectively. Live measurements explained 93% of carcass retail product weight and 39% of carcass retail product percentage. Lower accuracies were observed for pistola retail product weight (R²=0.87) and percentage (R²=0.33). Accuracies for fat trimmings weight and percentage were 79% and 55%, respectively. Ultrasound rump fat thickness showed greater correlations with retail product and fat trimmings (weights and percentages) when compared with ultrasound backfat thickness. The weight and percentage of retail products and of trimmable fat can be estimated in Nellore steers from live animal measurements, with similar accuracy to equations developed based on carcass measurements obtained at slaughter.

The present study was conducted to assess carcass features, physicochemical and sensory parameters of meat from steers finished on three types of pastures: natural pasture; natural pasture improved, fertilized and oversown with winter species; and annual summer grassland. The experiment was conducted from December 14, 2009 to November 30, 2010, with treatments distributed in a completely randomized design with a different number of replicates. Animals were used as experimental units. Experimental animals were Aberdeen Angus steers with twenty months of initial age and 354±27.4 kg of live weight, on average. The highest average daily gains were obtained for the annual summer grassland. There was no effect of treatments on carcass conformation. The highest carcass yield was obtained on the improved natural pasture. Forequarter yield, side cut yield and longissimus muscle area were similar between the pastures. Moisture and total lipids were not affected by the pasture. Thawing and cooking losses were higher in improved natural pasture and lower in sorghum pasture. Regardless of the treatment, the meat had luminosity ranging from intermediate to dark, high in red, high in yellow, and considered within the normal range for beef. Meat of higher shear force was found in natural pasture, and lower shear force was observed in meat from annual summer grassland. Average live weight daily gain explained 18% of the shear force. Sensory evaluation by duo-trio test showed differences between samples from distinct pastures in flavor. All the studied systems allow for desirable characteristics in carcass and meat.

Avaliou-se a viabilidade de abater animais de distintos grupos raciais com até quatro dentes em diferentes tipos de pastagem: natural, adubada, e melhorada por fertilização e sobressemeadura de espécies hiberno-primaveris. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições. Os dados foram agrupados em estações do ano (inverno e primavera) e submetidos à análise de variância. Foram utilizados novilhos de corte Angus e mestiços, ambos com média de idade inicial de 20 meses. A massa de forragem total e a altura do pasto apresentaram diferenças entre os tipos de pastagem e as estações do ano. A taxa de lotação e a massa de forragem verde sofreram interação entre o tipo de pastagem e a estação do ano. O ganho por área ao longo do experimento foi maior na pastagem adubada (259 kg/ha) e melhorada (263 kg/ha) em comparação à pastagem natural (126 kg/ha). O ganho médio diário foi maior para os novilhos Angus (1,087 kg/dia) e na estação de inverno (1,251 kg/dia). Não houve diferença para a área de olho-de-lombo entre o tipo de pastagem e grupo racial na data do abate. A espessura de gordura subcutânea sofreu interação entre o tipo de manejo e o grupo racial, uma vez que novilhos mestiços depositaram mais gordura na pastagem adubada e novilhos Angus na melhorada. Animais mestiços atingiram menor peso ao abate (505 kg), porém maior rendimento de carcaça (51,6%). Somente os animais mantidos na pastagem natural não atingiram acabamento suficiente para a comercialização. A utilização de fertlizantes e sementes na pastagem natural possibilita o abate de novilhos precoces independente do grupo racial. O ambiente pastoril determina diferentes respostas produtivas conforme a genética utilizada. O cruzamento é uma alternativa para incrementar atributos importantes da carcaça e diminuir o tempo de terminação.

The viability for slaughtering steers of distinct breeds with four teeth at most, on different types of pasture (natural, fertilized and fertilized with overseeding) with winter species was evaluated. The experimental design was randomized blocks with three replicates (padlocks). Data were analyzed according to the seasons (winter and spring) and submitted to analyses of variance. Angus calves and crossbred calves were used, both 20 months of age on average. Total forage mass and the pasture height showed differences between pasture type and seasons. Carrying capacity rate and green forage mass showed interaction between pasture type and season. Yield per unit area during the experimental period was higher in fertilized (259 kg/ha) and oversown pasture (263 kg/ha) than natural pasture (126 kg/ha). Average live-weight gain was higher for the Angus steers (1.087 kg/day) and during the winter (1.251 kg/day). Rib eye area did not show statistical difference between the pasture type and breeds at slaughtering time. Fat thickness showed interaction according to pasture and breeds, where crossbred steers were fatter on fertilized pasture and Angus steers were fatter on oversow pasture. Crossbred animals got lower slaughtering weight (505 kg), yet higher carcass yields (51.6%). Only steers kept on natural pasture did not reach enough fatness for commercialization. The use of fertilizer and seed on the natural pasture allows for slaughtering young steers regardless of the breed. Pasture condition allows different productive performances according to the animal genetics used. Crossbreeding is an alternative to increase important attributes on carcass and to reduce the finishing phase duration.

Avaliou-se a repetibilidade da mensuração de imagens de ultrassom da área do músculo longissimus dorsi (AOL) e das espessuras de gordura subcutânea do lombo (EGL) e da garupa (EGG). Imagens de ultrassom tomadas no lombo (entre a 12ª e a 13ª costela) e na garupa (entre os músculos gluteus medium e biceps femoris) de novilhas Nelore de 14 a 22 meses de idade foram classificadas em aceitáveis, marginais e rejeitáveis. As imagens aceitáveis e marginais foram mensuradas duas vezes por três técnicos em diferentes níveis de treinamento. Foram estimadas as repetibilidades entre e dentro de técnicos por classe de qualidade da imagem, para determinação do efeito da qualidade da imagem e do técnico no valor absoluto da diferença entre a primeira e a segunda mensuração dessas características. A repetibilidade para as imagens aceitáveis foi maior que para imagens marginais, tanto entre como dentro de técnicos. Na análise da diferença absoluta entre a primeira e a segunda interpretação, foram significativos os efeitos de técnico para AOL e EGL e de classe de qualidade da imagem para AOL. Em geral, o técnico com maior experiência apresentou maiores valores de repetibilidade. É recomendável que a mensuração de imagens de animais de mesmo grupo contemporâneo seja feita por um único técnico.

The repeatability of ultrasound image measurements of the longissimus dorsi muscle (AOL) and of the rumpfat (EGG) and backfat (EGL) subcutaneous thickness was evaluated. Ultrasound images taken from the back (between 12th and 13th ribs) and from the rump (between gluteus medium and biceps femoris muscles) of Nelore heifers at 14 and 22 months of age were classified as acceptable, marginal and rejected. The acceptable and marginal images were measured twice by three technicians at different levels of training. It was estimated repeatabilities among and within technicians by class of image quality in order to determine effect of image quality and of the technician at the absolute difference value between the first and second measurement of those traits. The repeatability for acceptable images was higher than for marginal images, for both among and within technicians. Regarding to the absolute difference analyses between the first and second interpretation, the effects of the technician for AOL and EGL and quality class of image for AOL were significant. In general, the repeatability was higher for the most experienced technician. It is advisable that measurements of images in the same contemporaneous group should be done by one single technician.

Foram utilizados 102 animais para desenvolver equações de predição a fim de estimar a composição do corte traseiro da carcaça bovina a partir de medidas ultra-sônicas obtidas no animal vivo e comparar estas equações às desenvolvidas a partir de medidas na carcaça. As equações de predição foram desenvolvidas utilizando-se o procedimento estatístico de seleção de variáveis de todas as regressões possíveis e o de seleção de variáveis Stepwise. Os modelos finais utilizando variáveis obtidas no animal vivo incluíram o peso vivo na data do ultra-som (PVUS), a área do músculo Longissimus (AOLUS) e a espessura de gordura subcutânea (EGSUS) para estimar o peso (PCTT; R² = 0,78) e a porcentagem (RCTT; R² = 0,18) dos cortes do traseiro. As variáveis obtidas a partir de modelos na carcaça incluíram o peso de carcaça quente (PCQ), a área do músculo Longissimus (AOLC), a espessura de gordura subcutânea (EGSC), o acabamento (ACAB) e a conformação (CONF) para estimação do peso (PCTT; R² = 0,89) e da porcentagem (RCTT; R² = 0,67) dos cortes do traseiro. As equações de predição desenvolvidas a partir de modelos no animal vivo e na carcaça são úteis para estimar os cortes comerciais do traseiro da carcaça.

One hundred two animals were evaluated to develop prediction equations for estimating hind-quarter composition from live animal ultrasound measurements and to compare these equations with those developed from carcass measurements. To develop prediction equations used all-possible regressions procedure for variables reductions and stepwise regression. Final models using live animal variables included live weight (PVUS), Longissimus muscle area (ULMA) and fat thickness (UFAT) for weight (PCTT; R² = 0.78) and percent (RCTT; R² = 0.18) of hind-quarter retail product. The models using variables carcass included hot carcass weight (HCW), carcass Longissimus muscle area (CLMA) and carcass fat thickness (CFAT) and Conformation (CONF) for weight (PCTT; R² = 0.89) and percent (RCTT; R² = 0.67) of hind-quarter retail product. Results indicate that composition predictions equations developed from live animals and ultrasound measurements can be useful to estimate yield hind-quarter retail product.

Foram utilizados 162 animais, avaliados em dois anos para determinar a exatidão do ultra-som em estimar a espessura de gordura subcutânea (EGSC) e a área do músculo Longissimus (AOLC) no sítio anatômico entre a 12ª e 13ª costelas. Dentro de 24 horas antes do abate, foram mensuradas por ultra-som a espessura de gordura subcutânea (EGSUS) e a área de músculo Longissimus (AOLUS). Os coeficientes de correlação simples entre as características medidas por ultra-som e a espessura de gordura subcutânea e área do músculo Longissimus da carcaça foram de 0,95 e 0,97, respectivamente. Diferenças entre medidas ultra-sônicas e da carcaça foram expressas em base atual (EDIFF e ADIFF) e em base absoluta (EDEV e ADEV) para espessura de gordura e área do músculo Longissimus, respectivamente. As médias da EDIFF e ADIFF indicaram que o ultra-som superestima a EGSC em 0,16 mm e subestima a AOLC em 0,26 cm² considerando-se ambos os anos. As médias globais da EDEV e ADEV, que são indicações da taxa média de erro, foram 0,34 mm e 1,28 cm², respectivamente. A análise do efeito do ano revelou que EDIFF foi maior no ano 1 e que ADIFF foi maior no ano 2. A análise da EDIFF indicou que animais com EGSC <2 mm foram superestimados e com EGSC >4 mm serem subestimados pelo ultra-som. Similarmente, houve tendência de animais com AOLC <50 cm² foram superestimados e com áreas >50 cm² foram subestimados por ultra-som. Os erros-padrão de predição ajustados para viés das medidas ultra-sônicas foram de 0,40 mm para espessura de gordura subcutânea e de 1,66 cm² para área do músculo Longissimus. Estes resultados indicam que o ultra-som pode ser um estimador acurado das características de carcaça em bovinos de corte.

One hundred sixty-two animals were used during a 2-year period to evaluate the accuracy of ultrasound measurements to estimate carcass subcutaneous fat thickness (CFAT) and area of Longissimus muscle located between the 12th and 13th ribs (CLMA). Twenty-four hours before slaughter animals were ultrasonically measured to determine subcutaneous fat thickness (UFAT) and area of Longissimus muscle (ULMA). The correlation coefficients between ultrasound measurements and CFAT and CLMA were 0.95 and 0.97, respectively. Differences between ultrasonic and carcass measurements were expressed in actual (FDIFF and RDIFF) and absolute (FDEV and RDEV) basis. Means of FDIFF and RDIFF in both years indicated that ultrasound overestimated CFAT by 0,16 mm and underestimated CLMA by 0.26 cm². Overall means of FDEV and RDEV were 0,34 mm and 1.28 cm², respectively. Analysis of year effects showed that FDIFF was greater in year 1 while RDIFF was higher in year 2. FDIFF indicated that ultrasound measurements overestimated CFAT in animals with <2 mm CFAT and underestimated CFAT in those with >4 mm CFAT. Similarly, animals with CLMA <50 cm² were overestimated while those with CLMA >50 cm² were underestimated. Standard errors of prediction adjusted for bias of ultrasound measurements were of 0.40 mm for standard error prediction of subcutaneous fat thickness and 1.66 cm² for standard error prediction of area of Longissimus muscle. These results suggested that ultrasound can be an accurate estimator of carcass traits in beef cattle.

O trabalho foi realizado com o objetivo de avaliar a influência do desmame aos 100 (DP) ou 180 (DC) dias de idade no desenvolvimento de fêmeas Braford até os 18 meses. As bezerras do DP foram suplementadas diariamente por 63 dias a 1% do peso vivo com ração comercial contendo 18% de proteína bruta e 74% de nutrientes digestíveis totais. Avaliou-se o ganho médio diário do nascimento aos 205 dias (G205), deste aos 365 dias (G365) e do último aos 550 dias (G550). Tomou-se o peso vivo ajustado aos 205 (P205), 365 (P365) e 550 dias de idade (P550). Ao sobreano, os escores visuais de conformação (C), precocidade (P) e musculatura (M) foram avaliados e a área de olho de lombo (AOL) e a espessura de gordura subcutânea (EGS), medidas pela técnica de ultra-som. O G205 e o P205 foram significativamente inferiores para as novilhas do DP (0,752 kg/dia; 187,0 kg) em relação às novilhas do DC (0,885 kg/dia; 214,1 kg). Entretanto, as novilhas do DP tiveram G365 significativamente superiores (0,231 kg/dia) às novilhas do DC (0,112 kg/dia), ocasionando P365 semelhantes entre tratamentos (DP = 223,9 kg; DC = 231,9 kg). O G550 não diferiu entre tratamentos, sendo 0,525 kg/dia para as novilhas do DP e 0,513 kg/dia para as novilhas do DC. Conseqüentemente, o P550 também não sofreu influência da idade de desmame (DP = 320,6 kg; DC = 326,3 kg). Os escores visuais de C, P e M não foram influenciados pela idade de desmame, sendo as médias para as novilhas do DP de 4,0; 4,1 e 3,6 para C, P e M e para as do DC de 4,2; 4,1 e 3,9, respectivamente. A idade de desmame também não influenciou a AOL (DP = 41,4 cm²; DC = 43,3 cm²) e a EGS (DP = 2,5 mm; DC = 2,7 mm). Os resultados indicam que novilhas desmamadas aos 100 dias de idade são mais leves ao desmame, porém, com nível nutricional adequado, alcançam aos 12 e 18 meses pesos vivos semelhantes às desmamadas aos seis meses de idade.

This work was conducted with the aim to evaluate the influence of weaning age at 100 (EW) or 180 (CW) days old on the growth of Braford heifers until approximately 18 months old. The calves of EW were daily supplemented during 63 days, at quantity of 1% of their live weight, with a comercial ration with 18% of crude protein and 74% of total digestible nutrients. Average daily gain from birth to 205 days (G205), from this one until 365 days (G365) and from the last one until 550 days (G550) were evaluated. Live weight adjusted at 205 days (W205), at 365 days (W365) and at 550 days old (W550) were recorded. At yearling age, the visual scores of conformation (C), precocity (P) and musculature (M) were evaluated and the rib eye area (REA) and the subcutaneous fat thickness (SFT) were measured by ultrasound technique. G205 and the W205 were significantly lower for EW heifers (0.752 kg/day; 187.0 kg) than CW heifers (0.885 kg/day; 214.1 kg). However, EW heifers had G365 significantly higher (0.231 kg/day) than the CW heifers (0.112 kg/day) and, consequently, both were similar at W365 (EW= 223.9 kg; CW= 231.9 kg). The G550 did not differ among treatments, being 0.525 kg/day for the EW heifers and 0.513 kg/day for the CW heifers. Consequently, W550 was not affected by weaning age (EW= 320.6 kg; CW= 326.3 kg). The visual scores of C, P and M were not affected by the weaning age, and the means for the EW heifers were of 4.0; 4.1 and 3.6 and for the CW heifers of 4.2; 4.1 and 3.9, respectively. Weaning age also did not affect REA (EW= 41.4 cm²; CW= 43.3 cm²) and the SFT (EW= 2.5 mm; CW= 2.7 mm). The results showed that heifers weaned at 100 days of age are lighter at weaning however, with an adequate post weaning nutritional level, they get at 18 months similar live weights to that ones weaned at six months of age.

Foram utilizadas 48 fêmeas suínas, para se determinar o rendimento de cortes comerciais, após abate e dissecação das carcaças dos animais aos 50, 60, 70, 80, 90, 100, 110 e 120 kg. Foram tomadas medidas ultra-sônicas in vivo para área de olho de lombo e espessura de toucinho. Os preditores utilizados para estimar o rendimento de carne magra foram espessura de toucinho e área de olho de lombo, além das medidas feitas nos diferentes cortes, como peso do corte do pernil, peso do músculo do pernil, peso do músculo da paleta, peso do músculo do carré, peso do músculo da copa, e assim por diante, além dos dados de peso de músculo da carcaça total, peso da gordura da carcaça total, peso de ossos da carcaça total e peso de pele da carcaça total. Foram desenvolvidas equações de predição por meio de regressão linear simples e múltipla, a partir dos dados da dissecação e das medidas in vivo da área de olho de lombo, feitas por ultra-sonografia em tempo real. As equações de predição para quantificar os principais componentes dos cortes suínos tiveram ótimo ajuste, com R² superiores a 0,84 para músculos e desvio-padrão residual de 0,62 a 0,94. A técnica de ultra-sonografia em tempo real apresenta alta correlação com as medidas tomadas nas carcaças dos suínos e, por isso, estima a quantidade de carne na carcaça e o rendimento dos cortes comerciais com grande precisão. Concluiu-se que a técnica de ultra-sonografia em tempo real é acurada para predizer as principais características das carcaças dos suínos medidas in vivo.

Forty-eight female pigs were used to determine the commercial cut yields after slaughter of the animals at 50, 60, 70, 80, 90, 100, 110 and 120 kg and dissection of the carcasses. Life ultrasonic measures were taken to measure the longissimus muscle area and for backfat thickness. The predictors used to estimate the lean meat yield were backfat thickness and longissimus muscle area. Besides the measures made in the different cuts, as ham cut weight, ham muscle weight, palette muscle weight, and carré muscle weight and pantry muscle weight. Additionally, the data of the total carcass muscle weight, total carcass fat weight, total carcass bone weight and total carcass skin weight, were also used. Prediction equations were developed using simple and multiple linear regressions using the logistic model from the dissection data and from the live ultrasonic measure data. Prediction equations were developed through out simple and multiple linear regressions using a logistic model from the dissection and live measures made by real-time ultrasound technology data. The prediction equation to determine the amounts the main components of the meat pork cuts presented a great adjustment, with R² superiors to 0.84 for muscles, with residual standard deviation (RSD) 0.62 to 0.94. The real-time ultrasonograph technology presented high correlation with the measures taking in the pork carcasses and could be used to estimate the amount of lean meat in the pork carcasses and also to estimate the commercial pork cut yields with great precision. It was concluded that the real-time ultrasonograph technology is accurate to predict the main pork carcass traits measured in the live animal.

Foram utilizadas 48 fêmeas suínas abatidas aos 50, 60, 70, 80, 90, 100, 110 e 120 kg para determinar os rendimentos de cortes comerciais e de carne magra na carcaça, visando-se estimar área de olho de lombo (AOL) e espessura de toucinho (ET), utilizando-se a técnica de ultra-sonografia em tempo real. Foram tomadas medidas ultra-sônicas in vivo, para AOL e ET; nas carcaças quentes, utilizou-se equipamento óptico da marca Hennessy, a fim de estimar a ET e profundidade de músculo (PM). As equações para estimar a quantidade de músculo na carcaça obtiveram R² entre 0,97 e 0,99, com desvio-padrão residual entre 0,27 e 0,73. Os valores de R² para área de olho de lombo, por ultra-som e pela medida direta nas carcaças, foram de 0,97 e 0,98, respectivamente, com desvio-padrão residual para as duas estimativas de 3,07 e 3,13. Os ajustes das equações para espessura de toucinho por ultra-som, espessura de toucinho óptico e espessura de toucinho medida diretamente na carcaça apresentaram R² de 0,99; 0,82; e 0,86, respectivamente, com desvio-padrão residual de 2,39; 3,13; e 2,91. As equações obtidas por regressões lineares e múltiplas, a partir dos dados da dissecação, ajustaram equações precisas para estimar rendimento de cortes comerciais e de carne magra nas carcaças de suínos entre 50 e 120 kg de peso corporal. A técnica de ultra-sonografia em tempo real é acurada para se estimarem a área de olho de lombo e a espessura de toucinho de suínos in vivo.

Forty-eight female pigs slaughter at 50, 60, 70, 80, 90, 100, 110 and 120 kg were used to determine commercial cut and of lean meat yields in pork carcass, with a view of the Longissimus muscle area and backfat thickness estimation by using the real-time ultrasound technology. Live ultrasonic measurements were taken for Longissimus muscle area and for backfat thickness and measures in the hot carcass were made, using optical Henessy equipment, to estimate the backfat thickness and Longissimus muscle depth. The regression equations to estimate the amount of muscle in the carcass obtained a R² between 0.97 and 0.99, with a residual standard deviation (RSD) between 0.27 and 0.73. The R² values for Longissimus muscle area obtained by ultrasound and for backfat thickness direct in the carcass, were 0.97 and 0.98, respectively, with a RSD of 3.07 and 3.13. The adjustment of the regression equations for ultrasound backfat tickness, for optical backfat tickness and for directly carcass backfat tickness measurement, presented R² of 0.99, 0.82, and 0.86, respectively, with a RSD of 2.39, 3.13, and 2.91. The fitted regression equations obtained by simple and multiple linear regressions from the dissection data set were precise to estimate commercial cuts and of lean meat of pork carcasses between 50 and 120 kg. The real-time ultrasonograph technology is accurate to estimate the Longissimus muscle area and backfat tickness in live animal.

Foram utilizadas 48 fêmeas suínas para se determinarem as curvas de crescimento de tecidos, após abate e dissecação das carcaças dos animais aos 50, 60, 70, 80, 90, 100, 110 e 120 kg. Os cortes realizados nas carcaças foram feitos de acordo com aqueles utilizados pela indústria. Em cada corte, separaram-se as quantidades de músculo, gordura, ossos e pele, para o cálculo de rendimento de tecidos. Foi utilizada a função alométrica estendida, para estimar e ajustar as curvas de crescimento. A quantidade de músculo na carcaça apresentou crescimento variando de 41,9 nos animais de 50 kg, a 44,1%, nos animais de 120 kg. A função alométrica estendida ajustou a curva para quantidade de músculo, com R² = 0,68 e desvio-padrão residual de 1,42. Os valores de R² para porcentagem de gordura foram de 0,80 e os de desvio-padrão residual, de 6,35, com aumento de 12,7 a 18,3% entre 50 e 120 kg. Quanto às curvas de crescimento para rendimento de cortes comerciais, os valores de R² foram variáveis, porém com desvios-padrão residuais baixos. Concluiu-se que a função alométrica estendida é acurada para estimar curvas de crescimento de tecidos calculados, em porcentagens do peso de suínos vivos abatidos entre 50 e 120 kg de peso corporal; a deposição de gordura é proporcionalmente maior que a deposição de tecido muscular; e os suínos depositam, em termos proporcionais, tecido muscular e gordura de forma crescente.

Forty-eight female pigs were used to determine tissue growth curves after slaughter of the animals at 50, 60, 70, 80, 90, 100, 110 and 120 kg and dissection of the carcasses. The lean cuts in carcass were made according to that used by Brazilian pork slaughters. In each cut it were separated muscle, fat, bone and skin amounts. The expanded allometric function was used to estimate and to fit the growth curves. The muscle amounts in carcass increased to 41.9% for animals at 50 kg and to 44.1% for animals at 120 kg. The expanded allometric function fitted the curve to muscle amount with R² = 0.68 and the residual standard deviation RSD = 1.82. The R² value for fat percentage was 0.80% and the (RSD) value was 6.35 with increase of 12.7% to 18.3% between animals at 50 to 120 kg. Concerning to the growth curves for the commercial meat cut yields, the R² value was variable, although with a RSD low. It was concluded that the expanded allometric function is accurate to estimate swine time growth curves calculated in percentage of weight of swine, slaughter between 50 and 120 kg and that fat deposition is proportionally higher than muscle deposition and that muscle and fat deposition, in percentage of carcass, increase from 50 to 120 kg.

O estudo foi realizado com o objetivo de verificar a utilização do peso vivo (PV) como estimador do peso da carcaça quente (PCQ), dos cortes dianteiro (PD), costilhar (PC) e serrote (PS), assim como, quantificar a relação do PV com o PCQ e principais cortes da carcaça (PD, PC e PS). Foram utilizados 58 novilhos Hereford, criados em campo nativo e abatidos com 36 meses de idade. As equações de regressão obtidas foram: PCQ=-3,97+0,474(PV); PS=4,32+0,050(PV); PC=-5,26+0,092(PV) e PD=-0,54+0.043(PV), todas altamente significativas (P<0,0001), apresentando coeficientes de determinação de 90,46%, 86,46%, 72,66% e 87,70%, respectivamente. Os resultados permitem concluir que o peso vivo é um bom estimador do peso de carcaça quente e dos cortes desta, podendo ser utilizado na seleção de animais para abate e na comercialização desses animais.

Fifty eight Hereford steers, raised under native pasture conditions, slaughtered with an average age of thirty months, were used to study the feasibility of the use of live wheight (PV) as an estimator of the hot carcass weight (PCQ) and of cuts such as fore quarter (PD), ribs (PC) and hind pistol (PS), as well as to quantify the relationship of live weight with hot carcass weight and the main carcass cuts (PD, PC and PS). The regression equations obtained were: PCQ =-3.7 + 0.474 (PV); PS = 4.32 + 0.50 (PV); PC = -5.6 + 0.92 (PV) and PD =-0.4 + 0.43 (PV), all of them highly significant (P<0.001), showing, respectively, the following determination coefficients: 90.6%, 86.6%, 72.6% and 87.0%. According to these values one might conclude that live weight is a good estimator of hot carcass weight and of its cuts, and may be utilized to sort animals for slaughter and when to sell them.