Prediction of kid carcass composition by use of joint dissection

Estimation of Carcass Tissue Composition from the Neck and Shoulder Composition in Growing Blackbelly Male Lambs

This study was designed to develop predictive equations estimating carcass tissue composition in growing Blackbelly male lambs using as predictor variables for tissue composition of wholesale cuts of low economic value (i.e., neck and shoulder). For that, 40 lambs with 29.9 ± 3.18 kg of body weight were slaughtered and then the left half carcasses were weighed and divided in wholesale cuts, which were dissected to record weights of fat, muscle, and bone from leg, loin, neck, rib, and shoulder. Total weights of muscle (CM), bone (CB) and fat (CF) in carcass were recorded by adding the weights of each tissue from cuts. The CM, CF and CB positively correlated (p < 0.05; 0.36 ≤ r ≤ 0.86), from moderate to high, with most of the shoulder tissue components, but it was less evident (p ≤ 0.05; 0.32≤ r ≤0.63) with the neck tissue composition. In fact, CM did not correlate with neck fat and bone weights. Final models explained (p < 0.01) 94, 92 and 88% of the variation observed for CM, CF and CB, respectively. Overall, results showed that prediction of carcass composition from shoulder (shoulder) tissue composition is a viable option over the more accurate method of analyzing the whole carcass.

Influence of the Use of Milk Replacers on Carcass Characteristics of Suckling Kids from Eight Spanish Goat Breeds

Simple Summary

Goats are important species due to their contributions to the development of rural areas. Spain has one of the largest goat populations in Europe; however, literature on goat carcasses is very scarce and, therefore, it is crucial to study the specific productive potential of each breed. Previous studies by our team on other Spanish goat breeds have shown some interactions between breed and rearing systems and, consequently, further analysis is necessary. This paper aims to contribute to the general knowledge on the subject.

Abstract

Since goat milk has a higher value than kid meat in Europe, some farmers rear kids with milk replacers, although some studies have stated that kids raised on natural milk yield higher-quality carcasses. Our previous studies showed some interactions between breed and rearing system on carcass and meat quality. This study evaluated the influence of the use of milk replacers on several carcass characteristics of suckling kids from eight Spanish goat breeds (Florida, Cabra del Guadarrama, Majorera, Palmera, Payoya, Retinta, Tinerfeña, and Verata). A total of 246 kids fed milk replacer (MR) or natural milk (NM) were evaluated. Carcass, head, viscera, and kidney fat weights, as well as several carcass measurements (round perimeter, forelimb width, carcass length, forelimb length, and carcass compactness index), were registered. Forelimbs were dissected to study tissue composition. For all studied variables, interactions were found between rearing system and breed. In general, the MR rearing system increased the head and visceral weights, as well as the length measurements and muscle percentages. Conversely, the NM rearing system increased carcass compactness and resulted in higher fat contents, independent of the deposit. The choice of one or another rearing system should be made according to the needs of the target market.

Comparison of the decision tree, artificial neural network and multiple regression methods for prediction of carcass tissues composition of goat kids

The aim of this study was to predict carcass tissue composition of goat kids using the decision tree with CHAID algorithm (DT) and artificial neural network (ANN) method in comparison with classical step-wise regression (SWR) analyse. Data were obtained from 57 goat kids of Gokceada breed. Predictor variables were pre-slaughter weight, several carcass measurements and indices, weights of different carcass joints and dressing percentage. R² values ranging from 0.212 to 0.371 indicating low to moderate accuracy were obtained for predicting muscle proportion. DT and ANN yielded similar R² values for predicting bone proportion. DT was the best prediction method for estimating proportions of subcutaneous fat (R² = 0.828) and intermuscular fat (R² = 0.789). According to DT analyses, cold carcass weight was the most important factor influencing bone proportion, while kidney knob and channel fat weight was the predominant factor influencing subcutaneous, intermuscular and total fat proportions. Consequently, the use of DT method can be considered to predict carcass fat proportions.

Comparison of meat quality characteristics and fatty acid composition of finished goat kids from indigenous and dairy breeds

The aim of the study was to compare the certain carcass and meat quality traits and also fatty acid composition of goat kids from indigenous breeds (Gokceada and Hair Goat) and dairy breeds (Saanen and Maltese). A total 40 male kids from Saanen, Gokceada, Maltese and Hair Goat breeds were collected from commercial farms after weaning. Kids were finished for 56 days with grower concentrate and alfalfa hay in the sheepfold until slaughter. Higher mean values were found for Saanen kids in terms of slaughter weight, hot carcass weight and real dressing compared with Maltese, Hair Goat and Gokceada kids under the same intensive conditions. On the other hand, there were no significant differences between breeds in terms of instrumental meat quality traits, except meat colour. Meat from Gokceada and Hair Goat kids had higher lightness and Hue angle values than Saanen kids after 24 h of blooming. High meat redness values were observed for Saanen kids after 0 and 1 h of blooming. Panellist appreciated cooked meat from Saanen and Maltese kids in overall acceptability. If the fatty acid composition of meat was taken into consideration, kids from Saanen and Gokceada breeds displayed better values, because of the lower ƩSFA percentage and higher desirable fatty acids (C18:0 + ΣMUFA + ΣPUFA) percentage than Maltese and Hair Goat kids. Our results indicate that male kids for Saanen which is dairy breed could be assessable for quality goat meat production.

Predicting beef carcass composition using tissue weights of a primal cut assessed by computed tomography

The potential of the composition of the forerib measured by X-ray computed tomography (CT) as a predictor of carcass composition was evaluated using data recorded on 30 Aberdeen Angus and 43 Limousin crossbred heifers and steers. The left sides of the carcasses were split into 20 cuts, which were CT scanned and fully dissected into fat, muscle and bone. Carcass and forerib tissue weights were assessed by dissection and CT. Carcass composition was assessed very accurately by CT scanning of the primal cuts (adj-R2 = 0.97 for the three tissues). CT scanning predicted weights of fat, muscle and bone of the forerib with adj-R2 of 0.95, 0.91 and 0.75, respectively. Single regression models with the weights of fat, muscle or bone in the forerib measured by CT as the only predictors to estimate fat, muscle or bone of the left carcass obtained by CT showed adjusted coefficients of determination (adj-R2) of 0.79, 0.60 and 0.52, respectively. By additionally fitting breed and sex, accuracy increased to 0.85, 0.73 and 0.67. Using carcass and forerib weights in addition to the previous predictors improved significantly the prediction accuracy of carcass fat and muscle weights to adj-R2 values of 0.92 and 0.96, respectively, while the highest value for carcass bone weight was 0.77. In general, equations derived using CT data had lower adj-R2 values for bone, but better accuracies for fat and muscle compared to those obtained using dissection. CT scanning could be considered as an alternative very accurate and fast method to assess beef carcass composition that could be very useful for breeding programmes and research studies involving a large number of animals, including the calibration of other indirect methods (e.g. in vivo and carcass video image analysis).

Growth performance, carcass quality, and noncarcass components of indigenous Caribbean goats under varying nutritional densities

Studies were conducted to determine the effects of feeding regimens on growth and carcass quality of the Creole goat, a genotype indigenous to the Caribbean. Forty kids weighing 9.0 +/- 1.2 kg of BW were reared indoors after weaning. Four supplement amounts were compared (10 kids per treatment): the G0 group received the basal diet (tropical forage, 8.8 MJ of ME and 108 g of CP/kg of DM) without concentrate, whereas the G100, G200, and G300 groups were offered 130, 230, and 310 g/d of concentrate (13.6 MJ of ME and 209 g of CP/kg of DM), respectively, in addition to the basal diet. The kids were slaughtered according to the standard procedure at 22 to 24 kg of BW for assessment of carcass traits and meat quality. Total DMI increased significantly, from 51 to 78 g/kg of BW(0.75), for G0 to G300 kids, whereas their ADG doubled from 42 to 84 g/d (P < 0.01; P < 0.01, respectively). The G:F values reached 125 to 130 for the G200 and G300 diets and were satisfactory compared with literature values. The carcass weight and dressing percentage (P < 0.01) increased from group G0 to G300, from 9 to 13 kg and from 42 to 51%, respectively. The proportions of the different cuts (related to the carcass weight) did not vary by diet. The conformation score increased significantly (P < 0.05) among the 4 groups from an average score of 3.2 to 4.0 (score/5). There was a significant effect (P < 0.01) of supplement amount on the accumulation of internal fat tissues: the kidney fat weight increased from 113 to 253 g from the G0 to the G300 group. Regardless of the feeding level and amount of internal fat, the carcasses had an acceptable fat cover score, which remained less than 2.6 (score/5). A significant effect was not observed for the ultimate pH and the main color variables of the meat. The cooking loss and the shoulder DM content varied (P < 0.05) with the supplement amount. By increasing the nutritional density of the diet, it was possible to obtain well-conformed and heavy carcasses, with no excessive fattening. Indigenous Creole goats have potential as meat animals when fed to gain more than 80 g/d. The optimal supplement supply with good-quality grass would be approximately 3.69 MJ of ME/d in our conditions. Further studies are required on meat sensory parameters and fatty acid profiles.

The use of dual-energy X-ray absorptiometry to estimate the dissected composition of lamb carcasses

A total of 140 male and female Dorset and Suffolk lambs were slaughtered according to four live weight classes (36-39kg, 41-44kg, 46-49kg and 51-54kg). Total tissue, fat and lean masses, and bone mineral content measured by dual-energy X-ray absorptiometry (DXA) were used to predict dissected tissue weights. The DXA total weights accurately predict half-carcasses and primal cuts weights (shoulder, leg, loin and flank) (R(2)>0.99, CVe<1.3%). The prediction of the half-carcass dissected fat percentage is weaker (R(2)=0.77, CVe=10.4%). Fatness prediction accuracy is equivalent for the shoulder, leg and loin (R(2) between 0.68 and 0.78, CVe between 10% and 13%). The R(2) obtained when predicting dissected lean content from DXA variables is 0.93 for the half-carcass and higher than 0.83 for all cuts other than flank (CVe are between 3.5% and 6.5%, except for the flank, which is 9.1%). The prediction of bone weight using the bone mineral content is not very accurate for the half-carcass, shoulder and leg (R(2): 0.48, 0.47 and 0.43; CVe: 10.2%, 12.0% and 11.6%, respectively). The situation improves, however, for the loin (R(2)=0.70, CVe=10.7%). In conclusion, DXA is an effective technology for predicting total weight and the amount of lean and fat in lamb carcasses and their primal cuts.