In vivo estimation of goat carcass composition and body fat partition by real-time ultrasonography

The accuracy of ultrasound measurements to assess goat carcass composition and the partition of body fat depots was evaluated. An ultrasound machine with a 5-MHz probe and image analysis was used to assess in vivo fat thickness and muscle depth in 56 Spanish Celtiberica adult goats, in lumbar and breast body regions. The goats were slaughtered and the weight of body fat depots recorded. Measurements corresponding to the in vivo ultrasound fat thickness and muscle depth were taken on carcasses. The left sides of carcasses were completely dissected into their components. The best relationships (r = 0.94, P < 0.01) between in vivo and carcass measurements of fat thickness were obtained when measurements were taken at the sternum, and the best anatomical point was located between the third and fourth sternebrae. The best correlation coefficients (r = 0.84) for muscle depth were found for measurements taken between the third and the fourth lumbar vertebrae at 2 cm from the middle of the vertebral column. Body weight and ultrasound measurements were used to fit the best multiple regression equations to predict carcass composition and the partition of body fat depots. All equations, with the exception of those for muscle quantity, omental, and total body fat depot amounts, were computed after performing a logarithmic transformation. Body weight in association with the ultrasound measurement taken at largest LM muscle depth, between the first and second lumbar vertebrae accounted for 90% of the muscle weight. Body weight was the first variable admitted into the prediction models of muscle, mesenteric fat, and total body fat and accounted for 82, 67, and 79% of the variation in tissue weights, respectively. The ultrasound measurement of fat thickness taken at the third sternebra was the first variable admitted into the prediction models for intermuscular fat, kidney and pelvic fat, and total carcass fat and accounted for by 73, 75, 71, and 79% of the variation in the weight of these fat depots, respectively. The ultrasound measurements taken in the breast region, particularly at the third and fourth sternebrae, were the most suitable for assessing fat thickness. The results of this experiment suggest that BW associated with some in vivo ultrasonic fat measurements allow the accurate prediction of goat carcass composition and body fat depots.     

The medium frequency (7.5 MHz) ultrasound image characteristics of cattle skin

SUMMARY The medium frequency (7.5 MHz) ultrasound images of cattle skin, as a model for other domestic animals, are described and compared with the published information for human skin. Although some difficulties are apparent in identifying the skin surface and therefore measuring tissue thicknesses, the papillary and reticular layers of cattle skin, about 2 and 4 mm thick, respectively, can be differentiated using a water standoff with a vegetable oil coupling medium. The difference in echo intensities and patterns between these dermal components supports the concept that ultrasound tissue characterisation using higher frequencies may prove to be a useful non-invasive procedure in livestock production and veterinary science. However, a detailed protocol is required. Care is needed in the choice of ultrasound coupling medium for good resolution of cattle skin. Higher frequency ultrasound equipment would be necessary for imaging the skin of small animals. Potential applications of this new technology are discussed.     

B-mode, real-time ultrasound for estimating carcass measures in live sheep: accuracy of ultrasound measures and their relationships with carcass yield and value

Accuracy and repeatability of live-animal ultrasound measures, and the relationships of these measures with subprimal yields and carcass value, were investigated using data from 172 wethers. Wethers were F(1) progeny from the mating of 4 terminal sire breeds to Rambouillet ewes and were finished in a feedlot to a mean BW of 62.9 kg (SD = 9.5 kg). Before transport to slaughter, LM area, LM depth, and backfat thickness were measured from transverse ultrasound images taken between the 12th and 13th ribs. After slaughter, these measures were taken on each carcass. Carcasses were fabricated into subprimal cuts, and weights were recorded. Ultrasound accuracy and repeatability were assessed using bias, SE of prediction, SE of repeatability, and simple correlations. Relationships among ultrasound and carcass measures, and between these measures and carcass yield and value, were evaluated using residual correlations and linear prediction models. Ultrasound bias approached 0 for LM area, and backfat thickness was overestimated by only 0.69 mm. The SE of prediction and r were 1.55 cm(2) and 0.75 for LM area, and 1.4 mm and 0.81 for backfat thickness, respectively. The SE of repeatability was 1.31 cm(2) and 0.75 mm for LM area and backfat thickness, respectively. At a standardized BW and backfat thickness, wethers with larger LM area and LM depth yielded larger and more valuable carcasses, and these relationships were detectable with ultrasound. For each SD increase in carcass LM area, dressing percentage increased 1.57 percentage points, gross carcass value increased US$5.12, and boxed carcass value increased US$6.84 (P < 0.001). For each SD increase in ultrasound LM area, dressing percentage increased 0.95 percentage points, gross carcass value increased US$3.15, and boxed carcass value increased US$3.86 (P < 0.001). When LM area effects were adjusted for carcass weight, the response in boxed carcass value attributed to disproportionate increases in high-value subprimal cut weights was small. Associations of dressing percentage and carcass value with ultrasound and carcass LM depth were significant (P < 0.01) but smaller than corresponding associations with LM area. These data indicate biological and economical incentives for increasing LM area in wethers, and live-animal ultrasound can provide reliable estimates of carcass measures. These results are applicable to terminal sire breeders and producers who market sheep using carcass-merit pricing systems.     

Predicting carcass composition of beef cattle using ultrasound technology.

We evaluated 20 slaughtered cattle with ultrasound before hide removal to predict fat thickness and ribeye area at the 12th rib for possible use in carcass composition prediction. Carcasses were fabricated into boneless subprimals that were trimmed progressively from 2.54 to 1.27 to .64 cm maximum fat trim levels. Stepwise regression was used to indicate the relative importance of variables in a model designed to estimate the percentage of boneless subprimals from the carcass at different external fat trim levels. Variables included those obtained on the slaughter floor (ultrasound fat thickness and ribeye area; estimated percentage of kidney, pelvic, and heart [KPH] fat; and warm carcass weight) and those obtained from carcasses following 24 h in the chill cooler (actual fat thickness, actual ribeye area, estimated percentage of KPH fat, warm carcass weight, and marbling score). At all different subprimal trim levels, percentage KPH was the first variable to enter the model. In the models using measures taken on the slaughter floor, ultrasound fat thickness was the only other variable to enter the model. Ultrasound fat thickness increased R2 and decreased residual standard deviation (RSD) in models predicting subprimals at 2.54-cm maximum fat trim; however, at 1.27- and .64-cm trim levels, R2 and RSD increased. Models using the same two variables (except actual fat instead of ultrasound) in the cooler were similar to those using data from the slaughter floor. However, as more cooler measurement variables entered the models, R2 increased and RSD decreased, explaining a greater amount of the variation in the equation. Ultrasonic evaluation on the slaughter floor may be of limited application compared with the greater accuracy found in chilled carcass assessment.     

Genome-wide association studies of preweaning growth and in vivo carcass composition traits in Esme sheep

Sheep are considered as a major contributor of global food security. Moreover, sheep preweaning growth traits as well as in vivo carcass composition traits such as ultrasonic measurements of Longissimus dorsi muscle depth (UMD) and back-fat thickness (UFD) are crucially important indicators of meat yield and hot carcass composition. Despite their relative importance for productivity and profitability of a sheep production system, detected QTL for these traits are quite scarce. Therefore, we implemented GWAS for these traits using animal mixed model-based association approach provided by GenABEL in Esme sheep. Three genome-wide and 14 individual chromosome-wide associated SNPs were discovered. As a result, ESRP1, LOC105613082, ZNF641, DUSP5, TEAD1, SMOX, PTPRT, RALYL, POM121C, PHIP, LOC101106051, ZIM3, PEG3, TRPC7, FBXL4, LOC105610397, LOC105616489 and DNAAF2 were suggested as candidates. Some of the discovered genes and involved pathways were already annotated to contribute growth and development in various species including human, mice and cattle. All in all, the results of this study are expected to strongly contribute to shed a light on the underlying molecular mechanisms behind growth and carcass composition traits, with potential implications on studies aiming faster genetic improvement, targeted low-resolution SNP panel designs and genome-editing studies.     

Estimation in vivo of the body and carcass chemical composition of growing lambs by real-time ultrasonography

The relationship between ultrasound measurements and empty body and carcass chemical composition was investigated. A 500-V real-time ultrasound with a 7.5-MHz probe combined with image analysis was used to make in vivo measurements to predict the empty body and carcass chemical composition of 31 female lambs of two genotypes, ranging in BW from 18.2 to 48.9 kg. Eleven ultrasound measurements of s.c. fat, muscle, and tissue depth were taken at four different sites (over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, at the 3rd sternebra of the sternum, and over the 11th rib, 16 cm from the dorsal midline). The single best predictor of empty body fat quantity and energy value was the s.c. fat depth over the 13th thoracic vertebra (r(2) = 0.904 and 0.912; P <0.01, respectively). Body weight was used with ultrasound measurements in multiple regression equations to establish the best independent variables combination for predicting chemical composition. Results showed that BW and two of the three ultrasound measurements (s.c. fat depth over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, and tissue depth over the 11th rib, 16 cm from the dorsal midline), explained 94.7 to 98.7% (P < 0.01) of the quantity of water and fat and the energy value variation in the empty body and carcass. Body weight per se was the best predictor of the quantity of protein, accounting for 97.5 and 96.8% (P < 0.01) of the variation observed in the empty body and carcass, respectively. The results of this study suggest that BW and some ultrasound measurements combined with image analysis, particularly subcutaneous fat depth over the 13th thoracic vertebra, allow accurate prediction of empty body and carcass chemical composition in lambs.     

Effect of breed-type on carcass weight and composition in sheep

The relative rate of increase in the carcass and its tissues with increasing empty body weight (EBW) or carcass weight respectively, was studied in male sheep from the Dorset Horn (29), Hampshire (21) and Sudan Desert sheep (31). The rate at which the carcass, muscle and bone increased in weight was the same in all breeds but the Desert sheep deposited fat at a slower rate than the other 2 breeds. At an equally adjusted EBW the Desert sheep had lighter carcasses than the Dorset Horn or Hampshire sheep. Desert sheep had more bone than the other 2 breeds at an equally adjusted cold carcass weight or muscle plus bone weight. At an equally adjusted total carcass fat weight the Desert sheep had significant (P < 0.01) more intermuscular and internal fat but less subcutaneous fat than the other 2 breeds. Future improvement plans of the Desert sheep may be directed towards reducing bone and increasing muscle content of the carcass.     

In vivo body composition estimation in nongravid and reproducing first-litter sows with deuterium oxide

An experiment was conducted with 64 first-litter sows to evaluate the efficacy of a D2O dilution procedure for measuring in vivo body composition during the reproduction cycle. Eight gilts were each infused at breeding, 57 and 105 d postcoitum and at 5 and 25 d postpartum, with equivalent numbers of nongravid controls infused at corresponding periods except at 5 d postpartum. Results from D2O dilution were compared with body water estimates obtained from chemical analysis. An early-equilibrating D2O pool (before 15 min) was similar quantitatively to empty body (ingesta free) water in nongravid and lactating animals, but not in pregnant sows. Because of inconsistent D2O equilibration patterns in gravid sows, the early pool was considered to have equilibrated with part but not all of the water in the conceptus products. Total body D2O space measurement obtained from data following equilibration of D2O in the entire body (1 to 2 h) overestimated total body water (including gastrointestinal water) by approximately 19%. Coefficients of determination for equations relating total body D2O space to empty body and maternal body water were .96 and .88, respectively, in gestating sows and .67 and .74, respectively, for lactating sows, while coefficients of variation were below 6% in all cases. Prediction equations were developed to estimate empty and maternal body components (protein, fat and ash) from body weight and D2O space. Accuracy of protein and ash weight prediction is lowest with this procedure because it involves the composite error of estimation of the other body components.     

Predicting percentage of intramuscular fat using two types of real-time ultrasound equipment

In the present study, 500 steers were used to develop models for predicting the percentage of intramuscular fat (PIMF) in live beef cattle. Before slaughter, steers were scanned across the 11th and 13th ribs using Aloka 500V (AL-500) and Classic Scanner 200 (CS-200) machines. Four to five images were collected per individual steer using each machine. After slaughter, a cross-sectional slice of the longissimus muscle from the 12th rib facing was used for chemical extraction to determine actual carcass percentage of intramuscular fat (CPIMF). Texture analysis software was used by two interpreters to select a region for determination of image parameters, which included Fourier, gradient, histogram, and co-occurrence parameters. Four prediction models were developed separately for each of AL-500 and CS-200 based on images captured by the respective machines. These included models developed without transformation of CPIMF (Model I), models based on logarithmic transformation of CPIMF (Model II), ridge regression procedure (Model III), and principal component regression procedure (Model IV). Model R2 and root mean square error of AL-500 Models I, II, III, and IV were 0.72, 0.84%; 0.72, 0.85%; 0.69, 0.91%; and 0.71, 0.86%; respectively. The corresponding R2 and root mean square error values of CS-200 Models I, II, III, and IV were 0.68, 0.87%; 0.70, 0.85%; 0.64, 0.94%; and 0.65, 0.91%; respectively. Initially, AL-500 and CS-200 prediction models were validated separately on an independent data set from 71 feedlot steers. The overall mean bias, standard error of prediction, and rank correlation coefficient across the four AL-500 models were 0.42%, 0.84%, and 0.88, respectively. For the four CS-200 models, the corresponding overall mean values were 0.67%, 0.81%, and 0.91, respectively. In a second validation test, only Model II of AL-500 and CS-200 was evaluated separately based on data from 24 feedlot steers. The overall mean bias, absolute difference, and standard error of prediction of AL-500 Model II were 0.71, 0.92, and 0.98%. For CS-200 Model II, the corresponding values were 0.59, 0.97, and 1.03%. Both AL-500 and CS-200 equipment can be used to accurately predict PIMF in live cattle. Further improvement in the accuracy of prediction equations could be achieved through increasing the development data set and the variation in PIMF of cattle used.     

Computer image analysis for prediction of carcass composition from cross-sections of Japanese Black steers.

Carcasses from Japanese Black steers were used to obtain prediction equations for carcass composition from information derived by computer image analysis of carcass cross-section images. The total weights of lean, fat, and bone were obtained from the left sides of 55 carcasses (Data Set I) and 18 carcasses (Data Set II) by physical dissection. The information such as total lean, fat, and bone areas in the cross-sections; muscle area, muscle circumference, short and long radius axis lengths, and direction of long radius axis; and geometric distance between any two muscle centers of gravity was obtained by scanning and image analysis of pictures of the cross-sections of the beef side at the 6th/7th rib interface. The coefficients of determination of the multiple regression equations estimated from Data Set I for kilograms of lean, fat, and bone were 0.76, 0.82, and 0.69, respectively, whereas for the percentages of lean, fat, and bone they were 0.57, 0.66, and 0.42, respectively. The multiple regression equations from Data Set I was applied to Data Set II in order to test the applicability of the prediction equations obtained. The correlation coefficients between the value predicted by the multiple regression equation and the measurement obtained by physical dissection for kilograms of lean, fat, and bone were 0.71, 0.72, and 0.70, respectively, whereas those for the percentages of lean, fat, and bone were 0.63, 0.44, and 0.29, respectively. The results indicate that the information obtained from the carcass cross-sections by the computer image analysis method can be used to predict carcass composition in Japanese Black steers.     

Accuracy of pregnancy diagnosis and prediction of foetal numbers in sheep with linear-array real-time ultrasound scanning

Pregnancy diagnosis was carried out in sheep by means of transabdominal linear-array real-time ultrasound scanning. Animals were restrained standing, and the transducer was placed on the hairless area of the ventral abdominal wall just in front of the udder. Of a total of 818 tests, 724 were performed between days 29 and 89 of pregnancy, 598 animals subsequently lambed and 126 were non-lambing animals. Only 8 of these tests were wrong: 3 false positive and 5 false negative diagnoses. Sensitivity, specificity, positive- and negative predictive values for these tests were 99.2%, 97.6%, 99.5%, and 96% respectively. There was evidence to indicate that the three false positive tests were caused by foetal mortality or unobserved abortions that took place after testing. Only 2 of the 5 false negative tests were carried out after day 39 of gestation. Counting of foetal numbers (1, 2 or 3) was performed in only some animals (n = 210) between days 45 and 77 of gestation. Three groups of animals (A: 89 ewes; B: 27 PMSG-treated ewes; C: 94 ewes) were analyzed separately. Overall accuracy of all predictions was 83.1%, 37.0% and 78.7% for the 3 groups respectively. Animals in group B produced only 3 or more lambs. Sensitivity of the countings of singles, twins and triplets or more were 90.4%, 90.4% and 50% respectively for the animals from group A and 91.9%, 86% and 21.4% for the animals from group C.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo prediction of extracellular and intracellular water in cattle and sheep using thiocyanate and urea

Two experiments were conducted in cattle and sheep to determine the earliest time for thiocyanate equilibration with extracellular water. In Exp. 1, nine animals were infused to determine marker concentrations and sampling times. In Exp. 2, five steers were infused and then exsanguinated for tissue analyses. Thiocyanate equilibrated 22 to 31 min after infusion with a pool size equivalent to expected extracellular water. Plasma thiocyanate half-life averaged 29 h. Tissue concentrations 24 or 48 h after thiocyanate infusion were 20 to 24% of those observed in plasma for heart muscle and kidney and 6 to 8% in liver and skeletal muscle. A procedure is proposed for the in vivo estimation of empty body water (urea dilution), extracellular water (thiocyanate dilution) and, by difference, intracellular water in cattle and sheep, requiring only three blood samples, an initial sample and two samples taken 12 and 28 min after intravenous infusion of a urea-thiocyanate solution.     

Prediction of carcass characteristics by real-time ultrasound in barrows and gilts slaughtered at three weights.

The carcass characteristics of 27 market barrows and 27 market gilts were evaluated at various times (n = 8) with real-time ultrasound (Aloka 210 DX) from approximately 20 kg until slaughter at three end points. The pigs were randomly assigned to slaughter weight groups of 91, 104.5, and 118 kg at weaning time. Correlations were determined over slaughter weight group and sex, and the accuracies of ultrasound measurements were also evaluated. The regressions of ultrasound 10th-rib fat and ultrasound longissimus muscle area on live weight were also developed. Correlations between actual and ultrasound-measured last-rib fat, 10th-rib fat, and longissimus muscle area were high (r = .91, .63, and .53, respectively; P less than .01). The accuracy of ultrasound longissimus muscle area prediction was lower for 118-kg pigs than for the two lighter groups, whereas the accuracy for prediction of last-rib fat was lower for 91-kg pigs than for the two heavier groups, as indicated by higher absolute differences (P less than .05). Last-rib fat and longissimus muscle area tended to be overestimated and 10th-rib fat tended to be underestimated by real-time ultrasound. Prediction of last-rib fat by ultrasound was more accurate for gilts than for barrows, as indicated by a lower absolute difference (P less than .05).     

Effect of feeding some West African browse foliages on growth and carcass composition in sheep

The effect of feeding foliage from Afzelia africana, Pterocarpus erinaceus or Khaya senegalensis on growth performance was evaluated using 32 West African Djallonké rams of about 8 months of age and with a mean initial body weight (BW) of 16.1 kg. The animals were randomly assigned to four groups of 8 animals and the experiment lasted for 13 weeks. All the animals received the same amount of hay from Andropogon gayanus and maize bran (200 g/day each) and dried foliage ad libitum. The control group was fed cottonseed cake in restricted amounts. The animals were able to consume higher amounts of A. africana than of P. erinaceus and K. senegalensis. There was no significant difference in growth rate between sheep offered A. africana or P. erinaceus, 62.9 and 58.8 g/d, respectively, but sheep offered K. senegalensis had a lower average daily gain, 48 g/day (P < 0.05) due to lower consumption of both energy and crude protein. Animals in the control group had the highest growth rate, 95.8 g/day. Sheep offered P. erinaceus and K. senegalensis had similar carcass characteristics and dressing percentage but lower fasted BW, empty BW, carcass weight and dressing percentage (P < 0.05) than sheep offered A. africana. These tree species can provide valuable feed during periods of feed shortage in the humid and sub-humid zones.     

Relationship between plasma leptin concentrations and carcass composition in fattening mutton: a comparison with ultrasound results

Positive relationships between circulating leptin concentrations and body fat content have been established in sheep when covering a rather broad range of age and/or body weight. The usefulness of leptin measurements for predicting carcass fat has yet to be evaluated specifically in fattening lambs. We therefore measured plasma leptin concentrations in 56 male lambs half and half Merino Mutton and Blackheaded Mutton. Subcutaneous fat thickness was measured by ultrasound 1 day before the lambs were slaughtered at 35 or 45 kg live weight. Carcass composition was determined by tissue dissection. The coefficients of correlations between leptin and the different amounts in fat depots ranged from 0.40 to 0.56 within the two live weight groups, and from 0.53 to 0.64 when taking the two groups together. Carcass fat percentage was estimated by leptin concentrations with the same accuracy (R2 = 0.34) as with ultrasound fat thickness. The accuracy was higher for leptin in the 35 kg-group whereas the accuracy was higher for ultrasound fat thickness in the 45 kg-group (R2 = 0.26 vs. 0.31). A combination of leptin and ultrasound fat thickness clearly enhanced the precision of estimation in all groups. Further investigations on the influence of factors such as breed, gender, duration of feed withdrawal or photoperiod on the association between leptin and carcass composition are necessary before the suitability of plasma leptin concentration for practical application can be evaluated.     

The relationship of various muscular and skeletal scores and ultrasound measurements in the live animal,and carcass classification scores with carcass composition and value of bulls

The relationships of live animal muscular and skeletal scores and ultrasound measurements and carcass conformation and fat scores with carcass composition and value were determined using 74 bulls. The animals consisted of 53 late-maturing breed crosses and 21 Holstein–Friesian slaughtered at 13 to 17 months of age. They were offered concentrates ad-libitum and 1 kg of grass silage dry matter per head daily for the final 139 day finishing period. Live animal muscular and skeletal scores and ultrasonic muscle and fat depth measurements of the M. longissimus dorsi were recorded at 8 to 12 months of age and pre-slaughter. Following slaughter, carcasses were classified for conformation and fatness and the right side of each carcass was dissected into meat, fat and bone. Carcass conformation and fat scores, (scale 1 to 15) ranged from 4.7 to 14.4 and 2.7 to 11.5, respectively. Pre-slaughter muscular scores showed significant positive correlations with kill-out proportion (r = 0.82), carcass meat proportion (r = 0.72), conformation score (r = 0.94), carcass value (r = 0.72), and the proportion of high-value meat cuts in the carcass (r = 0.49), and significant negative correlations with carcass bone (r = − 0.89) and fat (r = − 0.32) proportions. The associations between pre-slaughter muscular scores and proportion of high-value cuts in meat, perinephric plus retroperitoneal fat and fat score were not significant. Corresponding correlations with muscular scores at 8 to 12 months of age were generally lower than those recorded pre-slaughter. Correlations of ultrasound muscle depth with carcass traits showed similar trends but lower values to those obtained using the muscular scoring procedure. Ultrasound fat depth pre-slaughter was positively correlated with carcass fat proportion (r = 0.56) and fat score (r = 0.54), and negatively correlated with carcass meat proportion, proportion of high-value cuts and carcass value. Correlations with other carcass traits were not significant. Correlations of live animal skeletal scores with carcass traits were generally non-significant. A one unit (scale 1–15) increase in carcass conformation score was associated with significant increases in kill-out proportion, meat yield and carcass value of 11.9 g/kg, 11.9 g/kg and 5.8 cent/kg, respectively. Corresponding effects for a one unit change in fat score were − 2.9 g/kg, − 11.1 g/kg and − 4.9 c/kg. In conclusion, live animal muscular scores and ultrasound measurements and carcass conformation and fat scores were shown to be useful predictors of carcass composition and value.