Lean Yield Research Articles

Evaluation of Video Image Analysis (VIA) technology to predict meat yield of sheep carcasses online under abattoir conditions

Accurate estimates of carcass composition and eating quality are critical to the introduction and the success of a value-based marketing system (VBMS) and to help address increased consumer demands for leaner meat with higher quality. Currently in the UK, carcass composition is assessed by a subjective carcass classification system based on the EUROP conformation system, and a visual assessment of fat cover using a numeric fat score (“MLC Scoring”) (Anderson, 2003). Objective, image analysis based systems to classify carcasses into current classification categories have been studied (Allen and Finnery, 2000) and are in use in the beef industry in the EU. However, the introduction of automatic technologies such as VIA may also have considerable potential for prediction of lean meat yield of the carcass. There is growing interest in the possibility of developing payment criteria which are based on carcass meat yield. Therefore, the present research project investigated the potential of VIA technology to predict meat yield in terms of saleable meat yield (SMY), saleable primal meat yield (SPMY) and the carcass components leg, chump, loin and shoulder in lamb.

종료웅돈이 비육돈의 도체성적 및 부분육 실중량에 미치는 영향

Data of 369 commercial pigs produced from YorkshrexLancrace (YL F1) sows crossed with either Duroc (D), Berkshire (B) or BerkshirexDuroc(BD F1) as a terminal sire were used for the comparison of carcass garde and real retail cut yield. The crosses were performed between May, 2004 and May, 2006 at three interrlated farms belonging to the Gyeongam pork brand. The average carcass weight, carcass backfat thickness, carcass rate, AB grade ratio, lean meat yield were 84.78 ± 0.33 kg, 20.72 ± 0.237 mm, 76.25 ± 0.208%, 85.7% and 44.30 ± 0.158%, respectively. The average weights of real retail cut were 10.32 ± 0.062 kg belly, 4.17 ± 0.025 kg boston butt, 3.88 ± 0.022 kg rib, 8.40 ± 0.040 kg picnic, 15.15 ± 0.081 kg ham, 6.44 ± 0.043 kg loin and 0.94 ± 0.006 kg tender loin. In comparisons of carcass traits among cross types, carcass weights and backfat thicknesses of YL( )×B ( ), YL( )×B D( ) and YL( )×D ( ) were 85.73 ± 0.516 kg, 82.69 ± 0.788 kg and 84.79 ± 0.603 kg, respectively and 22.09 ± 0.356 mm, 20.33 ± 0.543 mm and 19.58 ± 0.415 mm, respectively. The YL( )×B ( ) cross showed the highest carcass weight and backfat thickness. The ratio of AB grade were 0.83 ± 0.030% in YL( )×B ( ), 0.97 ± 0.046% in YL( )×B D ( ) and 0.83 ± 0.035% in YL( )×D ( ), and the YL( )×B D( ) was higher than other two crosses. Weights of belly were 10.28 ± 0.092 kg in YL( )×B ( ), 10.59 ± 0.133 kg in YL( )×B D( ) and 10.25 ± 0.107 kg in YL( )×D ( ). Consequently, the YL( )×B D( ) cross showed the highest yield. In conclusion, there was no difference in carcass yield of commercial pigs derived from BD (F1) terminal sires with those from D terminal sires. However, weight of belly and AB grade ratio from BD (F1) terminal sires are higher than two others. Therefore, BD (F1) sire could be utilized as terminal one and contribute better profit for the pig industry.

Níveis de triptofano digestível em rações para suínos machos castrados de alto potencial genético para deposição de carne na carcaça dos 60 aos 95 kg

Foram utilizados 70 suínos machos castrados, híbridos comerciais de alto potencial genético para deposição de carne na carcaça (peso inicial de 60,0 ± 1,34 kg e peso final de 95,00 ± 0,97 kg), para avaliar o efeito dos níveis de triptofano digestível sobre o desempenho e as características de carcaça. Adotou-se delineamento experimental de blocos ao acaso, com cinco tratamentos (0,128; 0,136; 0,144; 0,152 e 0,160% de triptofano digestível, correspondentes às relações de 16, 17, 18, 19 e 20% de triptofano:lisina digestíveis), sete repetições e dois animais por unidade experimental. Os níveis de triptofano digestível não influenciaram o consumo de ração, o ganho de peso, a conversão alimentar, a espessura de toucinho e o rendimento de carne. O consumo de triptofano digestível aumentou linearmente com o aumento dos níveis de triptofano digestível na dieta. O nível de 0,128% de triptofano digestível, correspondente a uma relação triptofano:lisina digestíveis de 16%, atendeu às exigências de suínos machos castrados de alto potencial genético para deposição de carne na carcaça dos 60 aos 95 kg.

Effect of supplemental iron on finishing swine performance, carcass characteristics, and pork quality during retail display1

Crossbred pigs (n = 185) were used to test the effects of dietary Fe supplementation on performance and carcass characteristics of growing-finishing swine. Pigs were blocked by BW, allotted to pens (5 to 6 pigs/pen), and pens (5 pens/block) were allotted randomly to either negative control (NC) corn-soybean meal grower and finisher diets devoid of Fe in the mineral premix, positive control (PC) corn-soybean meal grower and finisher diets with Fe included in the mineral premix, or the PC diets supplemented with 50, 100, or 150 ppm Fe from Availa-Fe (an Fe-AA complex). When the lightest block averaged 118.2 kg, the pigs were slaughtered, and bone-in pork loins were collected during fabrication for pork quality data. During the grower-I phase, there was a tendency for supplemental Fe to reduce ADG linearly (P = 0.10), whereas in the grower-II phase, supplemental Fe tended to increase ADG linearly (P = 0.10). Even though pigs fed NC had greater G:F during the finisher-I phase (P < 0.05) and across the entire trial (P = 0.07), live performance did not (P > or = 0.13) differ among dietary treatments. There were linear increases in 10th-rib fat depth (P = 0.08) and calculated fat-free lean yield (P = 0.06); otherwise, dietary Fe did not (P > 0.19) affect pork carcass muscling or fatness. Moreover, LM concentrations of total, heme, and nonheme Fe were similar (P > 0.23) among treatments. A randomly selected subset of loins from each treatment was further fabricated into 2.5-cm-thick LM chops, placed on styrofoam trays, overwrapped with polyvinyl chloride film, and placed in coffin-chest display cases (2.6 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. During display, chops from NC-fed pigs and pigs fed the diets supplemented with 100 ppm Fe tended to have a more vivid (higher chroma value; P = 0.07), redder (higher a* value; P = 0.09) color than LM chops of pigs fed 50 ppm of supplemental Fe. Moreover, greater (P < 0.01) redness:yellowness ratios in chops from pigs supplemented with 100 ppm Fe indicated a more red color than chops from PC-fed pigs or pigs fed diets supplemented with 50 ppm Fe. In conclusion, however, increasing dietary Fe had no appreciable effects on performance, carcass, or LM characteristics, suggesting that current dietary Fe recommendations are sufficient for optimal growth performance, pork carcass composition, and pork quality.

Sire-maternal Grandsire Model and Sire Model in Estimation of Genetic Parameters for Average Daily Gain and Carcass Traits of Japanese Black Cattle

The objectives of this study were to estimate genetic parameters and sire breeding values for average daily gain (ADG) and carcass traits using sire-maternal grandsire model with REML approach, sire model with REML approach, sire model without relationships among sires and with REML and ANOVA approach, and to investigate advantages and disadvantages of these methods. Data were collected from 42,325 Japanese Black steers and heifers finished and slaughtered from 1991 to 2004. Traits analyzed in this study were average daily gain (ADG) during the fattening period, live weight at slaughter (LW), cold carcass weight (CW), estimated lean yield percentage (LYE), longissimus muscle area (LMA), subcutaneous fat thickness (SFT), rib thickness (RT), and marbling score (BMS). Bivariate analyses were also performed to obtain genetic and phenotypic correlation coefficients among traits. Estimated breeding values were obtained from each model, and simple and rank correlations among breeding values from each model were calculated. Estimates of heritability using the four models ranged from 0.25 to 0.31 in ADG, from 0.21 to 0.24 in LW, from 0.23 to 0.27 in CW, from 0.10 to 0.17 in DP, from 0.40 to 0.42 in LYE, from 0.19 to 0.31 in LMA, from 0.31 to 0.34 in SFT, from 0.26 to 0.33 in RT, and from 0.18 to 0.44 in BMS. The differences in heritability estimates using the four models seemed to be feasible in ADG, CW, DP, LMA, RT, and BMS. Genetic correlation coefficients of ADG with CW, SFT, RT and BMS were moderate to high and positive while the genetic correlation coefficients between ADG and LYE was low and negative. Correlation coefficients of BMS with SFT were negligible for both genetic and phenotypic correlations. The correlations of estimates evaluated from sire models with those from sire-maternal grandsire model were not large enough to convincing that breeding values using a sire model were corresponding to those using a sire-maternal grand sire model. If information of maternal grand sires are not available, the sire model with incomplete pedigree information included only sire of sire (Model 2) is optimal among the sire models evaluated in this study.

The relationship between different pork carcass lean yield definitions and the market carcass value

Cutout and dissection data from 265 carcasses were used to study the impact of the lean yield definition on their ability to discriminate lean carcasses from fat carcasses. The same data were used to evaluate the relationship between the various definitions of lean yield, such as the lean yield predicted by the Destron optical probe (LYDESTRON), the saleable meat yield (SMY), the Canadian lean yield (LY2000) and the lean meat percentage (TVM), and the market carcass value. Based on the highest number of carcasses assigned to the extreme grades (leaner and fatter), the TVM had the greatest discriminating capability based on carcass leanness. The correlation coefficients obtained between market carcass value and LYDESTRON, SMY, LY2000 and TVM were 0.14, 0.54, 0.36 and 0.23, respectively. These weak correlations demonstrate that lean yield alone does not adequately explain the variation in market value between carcasses. Lean yield therefore cannot be used to estimate market value independently of the definition used.

Growth Performance and Shedding of Some Pathogenic Bacteria in Feedlot Cattle Treated with Different Growth-Promoting Agents

Eighty steers with a mean body weight of 319 kg were used in a study to evaluate the effect of a growth-promoting implant (trenbolone acetate plus estradiol benzoate), monensin, and oxytetracycline on the steer performance and shedding of some foodborne pathogens. The steers were allotted to one of eight treatment combinations according to a randomized complete block design with 16 pens of five animals. Rectal fecal samples were collected before treatment commenced and over a period of more than 24 weeks to study the influence of treatments on the intestinal microbiology of the animals. Results supported the beneficial effect of the hormonal implant on the performance of feedlot steers (average daily gain, feed efficiency, and fat thickness), on carcass characteristics (hot carcass weight, lean yield), and economic value of the carcasses (P < 0.01). The levels of Escherichia coli in feces were not affected by treatments but remained high throughout the study period. Antibiotic-resistant isolates of E. coli were more frequently found as the study progressed but were not associated with any specific treatment. Also independently of treatment, we observed a reduction over time in the shedding of Campylobacter and Yersinia during the feeding period, whereas the shedding of Enterococcus was increased. The results of this study confirmed the beneficial economic effect of growth-promoting agents in beef production and showed that the agents tested did not specifically affect the overall microbial evolution of the animal gut. However, the study also showed, independently of the growth promoter used, the shedding of Campylobacter, Yersinia, and antibiotic-resistant E. coli in the feedlot environment. These bacteria also may be found in the colonic tissue of steers at slaughter and might be a source of carcasses contamination.

Níveis de energia metabolizável mantendo a relação lisina digestível: caloria em rações para suínos machos castrados em terminação

Foram utilizados 40 suínos machos castrados, híbridos comerciais com peso inicial de 60,1 ± 1,3 kg, em um estudo para avaliar os efeitos de diferentes níveis de EM, mantendo-se a relação lisina digestível:caloria sobre o desempenho e as características de carcaça. Foi utilizado o delineamento experimental de blocos ao acaso, com quatro tratamentos, cinco repetições e dois animais por unidade experimental. Os tratamentos corresponderam a quatro níveis de EM (3.100, 3.230, 3.370 e 3.500 kcal/kg de ração), nos quais foi mantida a relação de 2,41 g de lisina digestível/Mcal de EM. As rações foram fornecidas à vontade até o fim do período experimental, quando os animais atingiram 95,46 ± 2,89 kg. Os níveis de energia metabolizável influenciaram o consumo diário de ração, que reduziu linearmente. A conversão alimentar melhorou linearmente com o aumento dos níveis de energia metabolizável. Não houve efeito dos tratamentos sobre o consumo de energia, o ganho de peso diário, a eficiência de utilização da EM para ganho de peso, o rendimento de carcaça, a espessura de toucinho e o rendimento de carne magra. Níveis crescentes de energia metabolizável (3.100 a 3.500 kcal/kg), mantendo-se a relação lisina digestível:caloria na ração de suínos machos castrados, promovem melhora na conversão alimentar e redução no consumo de ração, sem alterar os valores do ganho de peso e das características de carcaça.

In vivo prediction of carcass composition and muscularity in purebred Texel lambs

A subjective assessment of the shape of the hind limb of purebred Texel lambs was evaluated as an in vivo predictor of carcass composition and muscularity. Lambs were taken from two flocks that were managed in a common environment, but which had either been selected for lean tissue growth rate or for improved conformation. Lambs were slaughtered at a mean age of 139 days at the end of an 11 week performance test in which they were reared indoors on a concentrate diet. Pre-slaughter measurements of live weight and ultrasonic muscle (UMD) and fat (UFD) depths at the position of the third lumbar vertebra, body length ( L) and a subjective leg shape score were recorded. After slaughter, measurements were recorded for carcass side length (SL), leg length ( T) and the maximum width ( A) and depth ( B) of the longissimus thoracis and lumborum (LTL) muscle. The side was fully dissected and various muscle weights and skeletal dimensions were used to calculate indices of muscularity as √(muscle weight/length) per unit length or as UMD/ L, A/SL or B/SL. The leg shape score was positively correlated with lean weight (0.23) and proportion (0.24), lean:bone ratio (0.25), measures of LTL dimensions (0.27–0.38) and muscularity traits (0.27–0.57) but was not significantly ( P > 0.05) correlated with fat weights or proportions in the carcass. Live weight was the best single predictor of lean weight (RSD = 0.403) and the addition of leg shape score (RSD = 0.381) to prediction equations was less effective than the inclusion of UMD and UFD in combination (RSD = 0.357). The addition of leg shape score to equations that included ultrasonic traits gave a significant ( P < 0.05) but marginal improvement in prediction (RSD = 0.347). The leg shape score was the most useful in vivo predictor of carcass muscularity traits and, with R 2 in the range 0.30–0.50, had comparable predictive power to a leg muscularity score derived from muscle weight and femur length. It is concluded that the leg shape score showed potential as a predictor of carcass muscularity that was largely independent of live weight and fatness at a fixed age and was marginally associated with superior lean yield and lean:bone ratio.

Níveis de proteína bruta e suplementação de aminoácidos em rações para leitoas mantidas em ambiente termoneutro dos 60 aos 100 kg

Foi conduzido um experimento para se avaliarem níveis de proteína bruta (PB) com suplementação de aminoácidos sintéticos em rações para leitoas mantidas em ambiente termoneutro. Trinta e cinco leitoas mestiças (Landrace x Large White) com peso médio inicial de 60,5 kg foram distribuídas em delineamento experimental inteiramente ao acaso, com cinco tratamentos (17,3; 16,0; 14,7; 13,4 e 12,1% PB, com suplementação de lisina, metionina, triptofano, treonina e valina, para se manter a qualidade protéica entre os tratamentos), sete repetições e um animal por unidade experimental. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 100,6 kg. Não se observou efeito da redução do nível de proteína bruta da ração sobre o desempenho (consumo de ração, ganho de peso e conversão alimentar) dos animais. As variáveis avaliadas na carcaça (comprimento da carcaça, área-de-olho de lombo, espessura de toucinho, rendimentos de carcaça, de carne magra, de gordura e de pernil) também não foram influenciadas pela redução do nível de PB das rações. Os tratamentos influenciaram os pesos absoluto e relativo do fígado, observando-se os maiores valores nos animais que receberam a ração com 16,0% de PB. A redução do nível de PB de 17,3 para 12,1% em rações para leitoas mantidas em ambiente termoneutro dos 60 aos 100 kg não prejudica o desempenho, desde que as rações sejam devidamente suplementadas com os aminoácidos essenciais limitantes.

Effects of L-carnitine, Selenium-enriched Yeast, Jujube Fruit and Hwangto (Red Clay) Supplementation on Performance and Carcass Measurements of Finishing Pigs

Fifty castrated crossbred (Landrace×Yorkshire) pigs, weighing an average of 60.6±3.1 kg were allotted to one of five treatments in a randomized block design to examine the effects of dietary inclusion of 0.1% L-carnitine (50 ppm carnitine), 0.1% selenium-enriched yeast (0.3 ppm selenium), 0.1% Jujube fruit or 0.1% Hwangto (Red clay) on pig performance and carcass quality. All diets were based on corn, wheat, soybean meal and wheat bran and were formulated to supply 13.8 MJ DE/kg. Dietary supplementation did not influence daily gain (p = 0.57), feed intake (p = 0.52), or feed conversion (p = 0.32). Digestibility of dry matter (p = 0.60), organic matter (p = 0.74), crude protein (p = 0.76), crude fibre (p = 0.70) and energy (p = 0.75) were also unaffected by inclusion of any of the additives. Tissue samples taken from the longissimus muscle showed that the levels of carnitine (p = 0.0001) and selenium (p = 0.0001) were significantly higher with dietary inclusion of carnitine or selenium-enriched yeast. Dietary treatment did not affect dressing percentage (p = 0.33), carcass lean yield (p = 0.99) or first, 10 th and last rib midline backfat depth (p = 0.45, 0.82 and 0.47, respectively). Dietary treatment also did not affect the percentages of tenderloin (p = 0.37), bacon (p = 0.36), fat and bone (p = 0.56), picnic shoulder (p = 0.25), skirt (p = 0.80), fresh ham (p = 0.31) or ribs (p = 0.79). However, pigs fed the diet containing Jujube fruit had a higher percentage of Boston butt than pigs fed the carnitine or selenium supplemented diets (p = 0.01). Pigs fed added Hwangto had a higher (p = 0.04) percentage of loin compared with pigs fed supplementary selenium or Jujube fruit. Loin muscle from pigs fed carnitine had a significantly lower Hunter colour value for L (whiteness, p = 0.004) and a higher value for a* (redness; p = 0.069). The overall results indicate that supplementation with L-carnitine and selenium-enriched yeast can produce pork containing higher levels of carnitine and selenium, which could provide health benefits for consumers of pork without detrimental effects on pig performance. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 2 : 217-223)

Performance and Carcass Composition of Growing-finishing Pigs Fed Wheat or Corn-based Diets

The objective of this experiment was to compare corn and wheat in finishing pig diets in order to determine whether performance, carcass quality, fatty acid composition or fat colour is altered by choice of cereal grain. A total of 126 crossbred pigs were used in this experiment. At the start of the experiment, a portion of the experimental animals were assigned to receive a wheat-based diet formulated using soybean meal as the sole source of supplementary protein. The remainder of the pigs were assigned to a corn-based diet formulated to supply a similar level of lysine (0.65%) and energy (3,300 kcal/kg DE). At two week intervals, a portion of the pigs on the corn-based diet were switched to the wheat-based diet so that a gradient was produced with pigs being fed the corn and wheat- based diets for different proportions of the finishing period ranging from 100% on wheat to 100% on corn. There were no significant differences in the growth rate of pigs fed the two diets (p = 0.834). Pigs fed wheat tended to consume slightly less feed (p = 0.116) and had a significantly improved feed conversion (p = 0.048) compared with pigs fed corn. Choice of cereal did not affect dressing percentage (p = 0.691), carcass value index (p = 0.146), lean yield (p = 0.134), loin fat (p = 0.127) or loin lean (p = 0.217). Fatty acid composition of backfat was unaffected by the cereal grain fed (p>0.05). Total saturated fatty acid content was 33.31% for both corn and wheat fed pigs (p = 0.997) while the polyunsaturated fatty acid content was 12.01% for corn fed pigs and 11.21% for wheat fed pigs (p = 0.257). The polyunsaturated/saturated ratio was 0.36 for pigs fed corn and 0.34 for pigs fed wheat (p = 0.751). Hunter Lab Colour Scores indicated no difference either in the whiteness or yellowness of the fat. In conclusion, wheat can substitute for corn in growing- finishing pig rations without detrimental effects on pig performance. There were no differences in either the fatty acid composition of backfat or in backfat colour indicating that the decision to use wheat vs. corn needs to be made on economic grounds rather than being based on their effects on fat quality. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 5 : 704-710)

Association of single nucleotide polymorphisms in the leptin gene with carcass and meat quality traits of beef cattle1

Studies with different populations are required to properly characterize the robustness of associations of polymorphisms in candidate genes with economically important traits across beef cattle populations before this sort of genetic information can be used efficiently in breeding and management decisions. The objective of this study was to evaluate the association of previously reported SNP in the bovine leptin gene with carcass and meat quality traits from a large sample of crossbred beef cattle. Five SNP (UASMS1, UASMS2, UASMS3, E2JW, and E2FB) were genotyped on 1,111 crossbred bulls, heifers, and steers. The measured traits included fat, lean, and bone yield (%) by partial rib dissection, grade fat, LM area, HCW, quality grade, LM i.m. fat, and tenderness evaluation of LM and semitendinosus muscle. Only four SNP were analyzed (UASMS1, UASMS2, E2JW, and E2FB), because UASMS1 and UASMS3 were completely linked. A uni-variate mixed-inheritance animal model was used to evaluate the association of either genotypes or haplo-types with the traits. The two leptin exon 2 SNP were associated with fat and lean yield and grade fat (E2JW, P < 0.01; E2FB, P < 0.05), and they interacted in their effect on LM tenderness (P < 0.01). The leptin promoter SNP were either not associated with any of the traits (UASMS2) or with fat yield only (UASMS1). Three haplotypes (TCAC, CCAT, TTAC) were at high frequency in the population (88%) and had similar effects on all the traits. Compared with the common haplotypes, one haplotype (CCTT) showed a significantly different effect on fat and lean yield and grade fat (P < 0.01), and one haplotype (TTTT) had a different effect on LM tenderness (P < 0.03). Therefore, important associations between SNP within the leptin gene with lean yield, fatness (fat yield and subcutaneous fat), and tenderness were detected. Results confirm some of the previously reported associations, but diverge with respect to others, showing that further efforts are required to validate some prospective associations.

출하체중에 따른 재래돼지와 랜드레이스의 도체 및 돈육의 이화학적 특성 비교

Results of meat quality, physicochemical characteristics, fatty acid and amino acid composition of the Korean Native Black Pig(70 and 90 kg of slaughter weight; KNBP) versus Landrace(110kg of slaughter) are as below. Compared with Landrace, the KNBP exhibited a greater lean meat yield, with no difference in backfat thickness between Landrace and KNBP. There were no difference in chemical composition between Landrace and KNBP, but pH, and cooking loss in the KNBP were superior value than those of the Landrace. These results, KNBP were affected in sensory property and cooking yield. Amino acid content of KNBP and Landrace were significant differences between Landrace and KNBP. Except for the methionine, essential amino acid contents of KNBP had significantly higher than those of Landrace. In the change of fatty acid composition, the Landrace had significantly higher percentages of palmitic(l6: 0), stearic(18: 0) and linolenic(18: 3) acids than that of KNBP, but linoleic acid(l8: 2) was decreased.

Porcine somatotropin alters body composition and the distribution of fat and lean tissue in the finisher gilt

The present study was designed to determine whether porcine somatotropin (pST) reduces whole animal and belly fat using dual energy X-ray absorptiometry and manual dissection. The study utilised 24 Large White × Landrace gilts selected at 16 weeks of age with an approximate liveweight of 80 kg and housed in individual pens. Gilts were stratified on liveweight into 8 blocks and 1 pig from each block was assigned to either 0, 5 or 10 mg per day of pST. Pigs were fed ad libitum a wheat-based diet containing 200 g crude protein, 10.2 g available lysine and 14.6 MJ DE/kg, to ensure that responses to pST were expressed. Feed intake and liveweight were measured on a weekly basis. An Hologic QDR4500A dual energy X-ray absorptiometer was used to determine lean, fat and ash composition of pigs initially and again 4 weeks later at the end of the experiment. After slaughter, the composition of the whole half carcass as well as the shoulder, ham, belly and loin primal cuts was determined with dual energy X-ray absorptiometry and verified with manual dissection. Daily pST treatment decreased feed intake (3440, 2710 and 2537 g/day for 0, 5 or 10 mg pST per day, respectively; P&lt;0.001) and decreased feed conversion ratio (2.95, 2.18 and 2.03 g/g; P&lt;0.001) even though there was no significant effect on daily gain. Pigs treated with pST deposited more lean tissue (620, 839 and 873 g/day; P&lt;0.05) and less fat (384, 218 and 176 g/day; P&lt;0.001) than control animals, but there was no effect of pST on ash deposition. As a consequence, pigs treated with 5 and 10 mg pST/day contained 5 and 9 kg less dissectible fat than control gilts, respectively. A dose dependent decrease in belly, loin, ham and shoulder fat was also observed, although the decrease in belly fat was more pronounced than for the whole carcass and other primal cuts. Overall, pST treatment has the potential to decrease carcass and especially belly fat in pigs and increase consumer acceptance of pork in markets that place a premium on carcass fat and lean yield in the belly region. The results determined with dual energy X-ray absorptiometry were confirmed by manual dissection.

Performance and carcass characteristics of growing-finishing pigs fed barley-based diets supplemented with Linpro (extruded whole flaxseed and peas) or soybean meal

The objective of this experiment was to determine the effects of feeding graded levels of Linpro (a 50:50 combination of extruded full-fat flax seed and peas) on pig performance and carcass traits, particularly the fatty acid composition of backfat. Eighty crossbred pigs (Camborough 15 Line female × Canabred sire, Pig Improvement Canada Ltd., Airdrie, AB) weighing an average of 22.7 ± 2.2 kg were assigned on the basis of sex, weight and litter to one of five dietary treatments in a 5 × 2 factorial arrangement (treatment × sex). The experimental diets were based on barley and soybean meal and contained 0, 7.5, 15, 22.5 or 30% Linpro during the growing period (22.7–69.7 kg) and 0, 6, 12, 18 or 24% Linpro during the finishing period (69.7–111.1 kg). Digestibility coefficients for dry matter were not significantly affected by incorporation of Linpro in the diet. Digestibility coefficients for crude protein (P = 0.01) and gross energy (P = 0.04) exhibited a cubic effect due to Linpro incorporation with the highest digestibility coefficients observed for pigs fed 7.5% Linpro. Over the entire experimental period (22.7–111.1 kg), daily gain was affected both linearly (P = 0.02) and quadratically (P = 0.04) by Linpro inclusion. The most rapid gains were obtained by pigs fed 7.5% Linpro (6% in finisher), while pigs fed 30% Linpro (24% in finisher) gained weight the slowest. Feed intake was not significantly affected by Linpro inclusion, while feed conversion exhibited a quadratic effect (P = 0.02) with pigs fed the highest and lowest levels o f Linpro showing the poorest feed conversion. Linpro inclusion, had no significant effects on carcass traits including slaughter weight, carcass weight, dressing percent, carcass value index, lean yield, loin fat or loin lean. Inclusion of 30% Linpro (24% in finisher) significantly (P &lt; 0.05) increased the levels of linolenic acid in backfat and this increase could provide significant health benefits for consumers of pork. Linpro would appear to be an acceptable alternative to soybean meal as a protein supplement for use in growing-finishing swine diets and can be incorporated at levels as high as 22.5% in the grower period and 18% in the finisher period without detrimental affects on pig performance. Key words: Swine, extrusion, flax, peas, digestibility, growth, backfat

Genetic parameters among growth and carcass traits of Canadian Charolais cattle

Genetic parameters for three growth and five carcass traits were estimated for Charolais using a combination of carcass progeny test, purebred field performance and pedigree data. Heritabilities and genetic and residual correlations were derived from variance components for birth weight (BWT, n = 54 221), 205-d weaning weight (WT205, n = 31 384), postweaning gain (PWG, n = 19 403), hot carcass weight (HCW, n = 6958), average subcutaneous fat thickness (FAT, n = 6866), longissimus muscle area (REA, n = 6863), marbling score (MAR, n = 6903) and estimated carcass lean yield percentage (PLY, n = 6852) with an animal model (n = 78 728) and restricted maximum likelihood. Breed of dam and contemporary group appropriate to each trait were included as fixed effects in the model, whereas random effects included direct genetic for all traits, maternal genetic for BWT and WT205, and maternal permanent environmental for WT205. Carcass traits were adjusted to a constant harvest age of 425 d. Heritability estimates of 0.53, 0.22, and 0.21 were obtained for direct components of BWT, WT205, and PWG, respectively, and maternal heritabilities were 0.16 and 0.10 for BWT and WT205, respectively. Direct × maternal genetic correlations for BWT (-0.49) and WT205 (-0.35) were negative. Heritabilities for HCW, FAT, REA, MAR, and PLY were 0.33, 0.39, 0.43, 0.34, and 0.46, respectively. Genetic correlations among direct effects for growth traits were moderately positive and generally uncorrelated with maternal effects across traits. Lean and fat deposition in the carcass generally had negative, unfavorable genetic correlations, although improvement in lean yield and marbling score may not be strongly antagonistic. Genetic correlations of direct and maternal components of growth traits with carcass traits suggested that selection for increased growth rate would not be antagonistic to improvement in carcass yield or meat quality. Key words: Carcass, Charolais, correlation, genetic parameters, growth

Avaliação de carcaças de suínos da raça Large White utilizando medidas convencionais

Visando estabelecer as medidas que melhor definem a quantidade de tecidos da carcaça de suínos, foram utilizados dados de rendimento de carne (RCARNE), rendimento de gordura (RGORD), rendimento de carcaça (RC), comprimento de carcaça pelo Método Brasileiro de Classificação de Carcaça (CCMB), comprimento de carcaça pelo Método Americano de Classificação de Carcaça (CCMA), espessura média de toucinho (ETM), espessura de toucinho a 4 cm da linha dorsal (P1), espessura de toucinho a 6,5 cm da linha dorsal (P2), espessura de toucinho a 8 cm da linha dorsal (P3), área de olho de lombo (AOL), relação carne:gordura (RCG) e rendimento de pernil (RP), obtidos em 664 suínos Large White. Inicialmente, procurando elucidar qual a importância e possíveis estruturas de relação existentes entre as variáveis, utilizou-se a análise multivariada de agrupamento (cluster analysis) e, em seguida, adotou-se o modelo de regressão linear múltipla, sendo as análises executadas por intermédio do SAS. Numa primeira fase, estimou-se o coeficiente de determinação parcial (Tipo II) de cada variável e, em uma segunda fase, adotou-se o procedimento de seleção de equações ajustadas denominado "Backward". Com exceção do RC, todas as medidas de carcaça avaliadas apresentaram correlação significativa com RCARNE e RGORD. As medidas ETM, P1, P2, P3 e RCG foram inversamente correlacionadas com RCARNE e diretamente correlacionadas com RGORD. Observou-se o contrário para as medidas CCMB, CCMA, AOL e RP. Na avaliação da qualidade da carcaça, para rendimento de carne são suficientes apenas as medidas ETM, AOL, RCG e RP, enquanto, para rendimento de gordura, além destas é necessária a mensuração da P1. As medidas de área de olho de lombo e espessura de toucinho, conforme propostas pelo MBCC mostraram-se como sendo as que melhor avaliam a quantidade de carne e gordura na carcaça.

Impact of genetic selection on management of boar replacement

Boars in an artificial insemination centre have been selected for their superior genetic potential, with ‘superior’ being defined as having traits the customer wants transmitted to his herd. The ability to meet the customers’ needs depends on the heritability of the trait, the geneticist's success in devising a selection scheme for the trait in balance with other economically important traits, and the boar's ability to produce sperm that can fertilise oocytes. Genetic evaluation research over the past 20 years has greatly increased the number of traits for which a boar can be selected: currently in the Canadian national program, these include age at 100 kg, backfat at 100 kg, feed efficiency, lean yield and litter size. In the near future, traits that are very likely to be added to this selection list include piglet survival, marbling, loin eye area and structure traits. In Canada, sires are ranked on two estimated breeding value (EBV) indices; one, focused on development of terminal sire lines, is based on the growth and yield traits and another, primarily focused on maternal line development, de-emphasises these traits and incorporates litter size. Boars that are in Canadian AI centres because of their excellent growth traits are typically in the top 5–10% of the national population for terminal sire line index, but they may be only average or substandard for litter size. Conversely, boars selected to be in the top 5–10% for conveying such reproductive traits as litter size may only be in the top 33% for growth traits. The more offspring from a superior boar in either of these indices, the faster the population average for the trait improves. The original sire gets knocked out of the elite group, is culled and replaced by a higher ranked young boar from the now improved general population. Although genetic superiority should govern an AI centre's selection and culling of boars, decision-making in real life is seldom that simple. Selection criteria may be contradictory as above, or a boar with truly superior traits may be excluded because a newly-developed molecular genetics test determines he carries an undesirable gene such as PSS, RN or others being developed. Selection for terminal sire or maternal line traits can ignore important practical factors that affect an AI centre—boars with superior genetics may not produce good semen because skeletal or penile problems prevent ejaculation, or because sperm production is poor due to a genetic flaw, disease, or some other cause. Interestingly, selection pressure for one trait may inadvertently select for a trait that is linked but whose linkage is unrecognised, and such unintentionally selected genes could benefit, harm, or have no effect on production traits. An AI centre serving a variety of customers must select boars in anticipation of their customers’ needs (including new, foreign and niche markets). A centre should also review its genetic evaluation results and progeny records, both to critique its own selection success and to try to detect unexpected linkages. Finally, an AI centre needs to predict its own future, selecting not just for production traits for the swine producer, but also for factors that enhance the centre's efficiency including boar conformation and temperament, and sperm quantity, quality and hardiness. Can we select for efficiency? Our colleagues in dairy cattle AI evaluate bull performance—should the swine industry consider evaluation of male fertility traits?

Effects of dietary lysine and energy density on performance and carcass characteristics of finishing pigs fed ractopamine1

Two hundred sixteen crossbred barrows and gilts (84.3 kg BW) were used to test the effects of dietary energy density and lysine:energy ratio (Lys:ME) on the performance, carcass characteristics, and pork quality of finishing pigs fed 10 ppm ractopamine. Pigs were blocked by BW and gender, allotted to 36 pens (six pigs per pen), and pens were assigned randomly within blocks to dietary treatments (as-fed basis) arranged in a 2 x 3 factorial design, with two levels of energy (3.30 or 3.48 Mcal/kg) and three Lys:ME (1.7, 2.4, or 3.1 g lysine/Mcal) levels. Pigs were fed experimental diets for 28 d, and weights and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Upon completion of the feeding trial, pigs were slaughtered and carcass data were collected before fabrication. During carcass fabrication, hams were analyzed for lean composition using a ham electrical conductivity (TOBEC) unit, and loins were collected, vacuum-packaged, and boxed for pork quality data collection. Energy density had no (P > 0.22) effect on ADG or ADFI across the entire 28-d feeding trial; however, pigs fed 3.48 Mcal of ME were more (P < 0.02) efficient than pigs fed 3.30 Mcal of ME. In addition, ADG and G:F increased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. Carcasses of pigs fed 3.48 Mcal of ME were fatter at the last lumbar vertebrae (P < 0.08) and 10th rib (P < 0.04), resulting in a lower (P < 0.03) predicted fat-free lean yield (FFLY). Conversely, 10th-rib fat thickness decreased linearly (P = 0.02), and LM depth (P < 0.01) and area (P < 0.01) increased linearly, with increasing Lys:ME. Moreover, FFLY (P < 0.01) and actual ham lean yield (P < 0.01) increased as Lys:ME increased in the diet. Dietary energy density had no (P > 0.19) effect on pork quality, and Lys:ME did not (P > 0.20) affect muscle pH, drip loss, color, and firmness scores. Marbling scores, as well as LM lipid content, decreased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. There was a linear (P < 0.01) increase in shear force of cooked LM chops as Lys:ME increased in the finishing diet. Results indicate that 3.30 Mcal of ME/kg (as-fed basis) is sufficient for optimal performance and carcass leanness in pigs fed ractopamine. The Lys:ME for optimal performance and carcass composition seems higher than that currently used in the swine industry; however, feeding very high Lys:ME (> 3.0 g/Mcal, as-fed basis) to ractopamine-fed pigs may result in decreased marbling and cooked pork tenderness.