Evaluation of estimated genetic merit for carcass weight in beef cattle: Live weights, feed intake, body measurements, skeletal and muscular scores, and carcass characteristics

Genetic merit for growth rate, expressed as expected progeny difference for carcass weight (EPD_CWT), is available for dairy and beef sires used in Ireland. The once predominantly Friesian (FR) dairy herd has experienced significant introgression of Holstein (HO) genes over the past two decades, and cross-breeding of dairy cows, not required to produce herd replacements, with beef bulls is common. The objective of this study was to compare growth rate, feed intake, live animal measurements and slaughter traits of progeny of Holstein–Friesian dairy cows and bulls of two contrasting maturity beef breeds namely Aberdeen Angus (AA) and Belgian Blue (BB), each selected for either high (H) or low (L) estimated genetic merit for carcass weight. Two dairy strains (FR and HO) were also included giving six genetic groups in total. A total of 170 male progeny from spring-calving cows were artificially reared indoors and subsequently managed together at pasture until the end of their second grazing season when they were assigned to one of two mean slaughter weights (i) 560 kg (Light) or (ii) 620 kg (Heavy). Daily feed intake was recorded during the first winter and during finishing. Body measurements were recorded four times during the animals' life, and linear scoring was carried out at 9 months of age and again at slaughter. Carcasses were graded for conformation and fatness (15 point scale). Slaughter and carcass weights per day of age for AAH, AAL, BBH, BBL, FR and HO were 782, 719, 795, 793, 804 and 783 (SE 12.9) g, and 415, 372, 438, 436, 413 and 401 (SE 5.8) g, respectively. Corresponding values for carcass weight, kill-out proportion, carcass conformation class (15 point scale) and carcass fat class (15 point scale) were 314, 283, 334, 333, 317 and 305 (SE 4.7) kg, 526, 518, 553, 550, 519 and 511 (SE 2.9) g/kg, 6.2, 5.4, 8.0, 7.9, 5.3 and 3.7 (SE 0.26), and 9.8, 9.3, 7.4, 7.2, 9.3 and 8.2 (SE 0.26). There were significant interactions between estimated genetic merit for carcass weight and beef breed with the differences between H and L mainly expressed for AA only. Feed intake differences between H and L animals were negligible and largely attributable to the differences in live weight. Following scaling for live weight, beef breeds of high estimated genetic merit for carcass weight had lower skeletal measurements, indicating greater compactness, with the effect more pronounced in AA. It is concluded that using beef sires of estimated high genetic merit for carcass weight on dairy cows increases growth rate and carcass weight of the progeny but the effect may not be similar for all breeds.     

Intake, live animal scores/measurements and carcass composition and value of late-maturing beef and dairy breeds

The objectives of this study were to compare the progeny of 1) late-maturing beef with dairy breeds and 2) Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems. The bull system included 50 late-maturing beef breeds and 22 Holsteins (HO) slaughtered at approximately 15 months of age, whereas the steer system consisted of 56 late-maturing beef breeds and 23 British Friesians (FR) slaughtered at approximately 24 months of age. Beef breeds were suckled until approximately 8 months of age, while dairy breeds were artificially reared until weaning at approximately 3 months of age. All animals were finished on an ad libitum concentrate diet. Mean live weight, live weight gain, carcass gain and feed efficiency were greater (P < 0.05) in beef than dairy breeds in both systems during the finishing period when offered concentrates. Although there was no difference in feed intake between beef and dairy breeds, intake expressed relative to live weight was lower (P < 0.001) in beef breeds in both systems. At 10 months of age and pre-slaughter, beef breeds had higher (P < 0.001) muscularity scores and greater scanned muscle depth (P < 0.001) than their dairy contemporaries. Carcass weight, kill-out proportion, carcass conformation score, meat proportion and value were greater (P < 0.001) and carcass fat and bone proportions were lower (P < 0.05) in beef than dairy breeds in both systems. Insulin concentrations were lower (P < 0.001) in beef than dairy breeds, whereas there was no difference in blood metabolites or IGF-1 concentrations. Feed intake expressed relative to live weight or feed efficiency did not differ between CH, LM, SM or BB sired progeny. Muscularity scores were greater (P < 0.05) in BB than SM, whereas skeletal scores were lower (P < 0.05) in LM than SM. Limousin had lower (P < 0.05) carcass gain per day of age than CH and SM, whereas SM had a lower (P < 0.05) carcass conformation score than BB and CH and a higher (P < 0.05) carcass fat score than CH. Simmental had a lower (P < 0.05) carcass meat proportion and a higher (P < 0.05) carcass fat proportion than CH, LM and BB, which were similar (P > 0.05). The improvement obtained for beef over dairy breeds in live weight gain was 12%, while the improvements in carcass gain and meat produced was 24% and 33%, respectively. This demonstrates that the importance of carcass data contributing to breed comparison studies cannot be over-emphasised.     

Evaluation of estimated genetic merit for carcass weight in beef cattle: Blood metabolites, carcass measurements, carcass composition and selected non-carcass components

In Ireland, a new beef genetic index has been developed. Growth rate is expressed as expected progeny difference for carcass weight (EPD_CWT) and is estimated on an across-breed basis. Cross-breeding of dairy cows with both Aberdeen Angus and Belgian Blue beef sires is widely practised. The objective of this study was to compare blood metabolites, slaughter traits and carcass composition of progeny from Holstein–Friesian dairy cows and Aberdeen Angus (AA), Belgian Blue (BB), Friesian (FR) and Holstein (HO) sires. The AA and BB sires were selected, within breed, to be of either high (H) or low (L) estimated genetic merit for carcass weight. A total of 170 male progeny from spring-calving cows and 42 sires (10 AA, 13 BB, 7 FR and 12 HO) were artificially reared indoors and managed together until the end of their second grazing season when they were assigned to either a Light (560 kg) or Heavy (620 kg) slaughter weight. Blood metabolite concentrations were measured six times throughout life and feed intake was recorded during the first and second winter. Carcass measurements and selected non-carcass components were recorded after slaughter and the right side of each carcass was dissected into lean, fat and bone. Differences in blood metabolite concentrations amongst genetic groups were negligible although there were some effects of the prevailing level of nutrition. M. longissimus area scaled for carcass weight was 0.220, 0.221, 0.260, 0.255, 0.212 and 0.208 (SE 0.004) cm²/kg for AAH, AAL, BBH, BBL, FR and HO, respectively. Carcass measurements scaled for carcass weight were greater for L, AA, HO and the dairy strains than for H, BB, FR and the beef breeds, respectively. There was no effect of estimated genetic merit for carcass weight on carcass composition. Statistically significant interactions between genetic merit and beef breed existed for some traits with the genetic merit effect largely evident for AA only. BB and the beef breeds had more lean, less fat and more high value lean in the carcass than AA and the dairy strains, respectively. It is concluded that genetic group had little effect on blood metabolite concentrations but there were some feeding level effects. Estimated genetic merit for carcass weight affected carcass weight, m. longissimus area and carcass measurements scaled for carcass weight but the effects were confined to AA. There were large effects of beef breed and dairy strain on carcass composition.     

Evidence for a breed specific association between PrP genotype and ultrasonic muscle depth but not for survivability, growth or carcass traits in sheep

The ARR allele of the prion protein gene is associated with resistance to classical scrapie, while the ARQ allele is associated with susceptibility. The objective of this study was to estimate the effect, on lamb growth and carcass traits, of replacing an ARQ allele with an ARR allele. Pedigree rams (22 Suffolks, 18 Texels and 18 Charollais) were sourced in pairs, from the same flock (by the same sire where possible), with one member being ARR/ARR and the other being ARQ/ARQ and these rams were progeny tested through single-sire mating in six flocks. Effects of ram genotype on reproductive performance of ewes and on growth and carcass traits of progeny were estimated using mixed model procedures with sire as a random effect. Ram genotype had no effect on litter size at birth or on lamb survival as measured by the number of lambs reared. The differences between the performance of progeny by ARR/ARR and ARQ/ARQ sires provided an estimate of the effect of substituting an ARR allele for an ARQ allele. This allele substitution had no effect on birth weight, growth rate, weight at 5 or 14 weeks, weight or ultrasonic fat depth at 120 days of age or on carcass classification traits (conformation, fatness) for the Suffolk, Texel or Charollais breeds. Substituting an ARR allele for an ARQ allele had a negative effect on ultrasonic muscle depth at 120 days for the progeny of Suffolk rams (P = 0.01) but had a positive effect on ultrasonic muscle depth at 120 days for the progeny of Charollais rams (P = 0.02). The ARR substitution effect was negative for slaughter age in the Suffolk (P < 0.05) and positive for carcass weight in Texel progeny (P < 0.05). The magnitude of these effects was quite small, however, and the overall results support the hypothesis that substituting an ARR allele for an ARQ allele has no important negative effect on lamb growth or carcass traits in any of the breeds examined.     

Carcass characteristics of Awassi ram lambs slaughtered at different weights

Thirty Awassi ram lambs were used to study the effects of slaughter weight on carcass characteristics. Lambs were slaughtered at three different live weights (20, 30, and 40 kg). Empty body weight, hot and cold carcass weights and non-carcass components increased (P < 0.001) at a steady rate between all slaughter weights. Body length, leg length, maximum shoulder width, width behind shoulders and gigot width increased (P < 0.001) as slaughter weight increased from 20 to 40 kg. Linear dimensions measured on the surface of the M. Longissimus also increased (P < 0.001) with increasing slaughter weight. The ratio between width and depth of the longissimus muscle decreased (P < 0.01) at a steady rate between 20 and 40 kg indicating that the muscle increased more in depth than width. Dressing-out percentage was higher (P < 0.001) for lambs slaughtered at 30 kg live weight compared to other weights. Total lean and total bone decreased (P < 0.05) as a percent of cold carcass weight while total fat, subcutaneous and intermuscular fat percentages increased (P < 0.05) with increasing weight. Subcutaneous fat percentage was not affected by increasing body weight between 20 and 30 kg. Intermuscular fat percent was higher in all cuts except the leg where subcutaneous fat % was higher. Muscle to bone ratio increased (P < 0.001) while muscle to fat ratio decreased (P < 0.001) with increasing body weight in the four major cuts and the whole carcass. In conclusion, slaughtering Awassi ram lambs at weights up to 30 kg resulted in higher dressing-out percentage and better carcass characteristics than ram lambs slaughtered at heavier weights.     

Effects of concentrate supplementation on carcass and meat quality attributes of feedlot finished Small East African goats

Effects of concentrate supplementation on carcass and meat quality of feedlot finished Small East African (SEA) goats were assessed using 23 animals (14.5 months old and 20.1 kg body weight). Goats were subjected to four levels of concentrate supplementation: ad libitum concentrate allowance (T100), 66% of ad libitum concentrate allowance (T66), 33% of ad libitum allowance (T33) and no concentrate (T0). All goats were slaughtered after 90 days of experimental period. The ad libitum concentrate intake attained by the goats was about 370 g DM/d. All concentrate-supplemented goats had similar (P > 0.05) total dry matter intake. T100 goats had 31 g and 14 g higher (P < 0.05) daily body weight gain than T33 and T66 goats, respectively. T100 and T66 goats were comparable in final live weight and empty body weight but both were heavier (P < 0.05) than that of T33 and T0 goats. Hot and cold carcass weights for both T100 and T66 goats were 3 kg heavier (P < 0.05) than that of T0 goats. Concentrate-supplemented goats had similar (P > 0.05) EUROP scores for carcass fatness. T100 and T66 goats had 6.5 and 3 units higher (P < 0.05) scores for conformation than T0 and T33 goats, respectively. Dressing percentage increased with levels of concentrate supplementation in a curvilinear fashion, with highest values in T66 goats. At 6 h post-mortem, muscle pH for concentrate-supplemented animals was significantly lower compared with T0 goats. Carcass fat content was 9% higher (P < 0.05) in concentrate-supplemented goats than in their contemporaries. No differences in cooking loss or shear force were observed among treatments, while these variables were affected by the type of muscle. It is concluded that feedlot finishing of SEA had limited effects on meat quality. Finishing SEA goats at 66% of their ad libitum concentrate intake, however, significantly improved weight gains and carcass fatness. Cost–benefit analyses are recommended before embarking on a large scale feedlot finishing of SEA goats.     

Carcass characteristics of Hanwoo (Korean cattle) from different sex conditions, raising altitudes and slaughter seasons

This study was carried out to investigate the carcass characteristics of Hanwoo (Korean cattle) from different sex conditions, raising altitudes and slaughter seasons. The total number of cattle used in this study was 3608 heads which comprised of 1336 bulls and 1660 steers. The data was analyzed according to sex condition (bull and steer), raising altitude (low: 0–100 m and high: 700–800 m) and slaughter season (spring, summer, autumn and winter). At 24 h post-slaughter, the carcasses were weighed and evaluated for carcass traits according to the Korean carcass grading standard by an official grader. Carcass weight, ribeye area, yield index and grade, and meat color, firmness and maturity scores of carcass from bulls were significantly higher (P < 0.001) than those from steers. Inversely, the backfat thickness, marbling score and quality grade of carcass from steers were significantly higher (P < 0.001) than those from bulls. The maturity score of carcass from a high area was significantly higher (P < 0.01) than that from a low area. The ribeye area of carcass from summer was significantly smaller (P < 0.05) than that from other seasons. The maturity score of carcass from the summer season was highest among that from other seasons and the lowest was that from the winter season. Marbling score and carcass quality grade from the winter season were highest among those from other seasons and the lowest were those from the autumn season. There were no significant interactions between sex condition and raising altitude on carcass traits except the ribeye area. There were significant interactions between sex condition and slaughter season on marbling score and carcass quality grade. There were no significant interactions between raising altitude and slaughter season on all of the carcass traits. There were significant interactions among sex condition, raising altitude and slaughter season on meat color score. It was concluded that sex condition affected muscle and fat depositions on the carcass, raising altitude affected maturity and slaughter season affected ribeye area, maturity and marbling.     

Finishing of dairy steers having grazed semi-natural grasslands

The objective of this study was to determine the effects of initial live weight, level of grain feeding, and length of finishing period on weight gain and carcass traits of dairy steers that had grazed semi-natural grasslands. Steers were subdivided by initial live weight (low vs. high) and were fed two levels of grain (0.5% vs. 1.0% of live weight day^− 1) during three different lengths of finishing period (3, 5 vs. 8 months). In total, 192 steers, initially 18 to 21 months of age, were fed grass–clover silage ad libitum. Steers fed high levels of grain had a higher dietary feed intake than steers fed low levels of grain (10.5 vs. 9.7 kg DM day^− 1; P < 0.001). Carcass weight gain (630 g) was highest and feed conversion (169 MJ metabolizable energy per kg carcass gain) was best in steers with 5 months of finishing. Steers with low initial weights had a higher daily carcass weight gain than initially heavy steers (614 vs. 571 g, P = 0.013). A high initial weight and a long finishing period resulted in heavier and fatter carcasses with a higher conformation score and lower proportions of valuable retail cuts and bone. In conclusion, high-quality carcasses can be produced when finishing dairy steers that previously have grazed semi-natural grasslands. Performance and carcass traits were more effected by initial weight and length of finishing period than by level of grain feeding.     

Carcass and meat quality traits of the Chato Murciano pig slaughtered at different weights

In order to evaluate the effect of slaughter weight and rearing system on the Chato Murciano pig carcass and meat quality traits, a total of 71 castrated male pigs were used. Forty-one pigs were reared in an outdoor system, divided in one heavy group (CHOHW) with an average live weight of 132.05 kg, and a second group with lower weights (CHOLW, 115.7 kg average). Simultaneously, 30 pigs were reared indoors and divided into one heavy group (CHIHW) with an average live weight of 144.3 kg, and a second group with lower weights (CHILW, 117.6 kg average).Heavier pigs showed higher values for several carcass parameters (hot carcass weight, carcass length, maximum perimeter of the ham, hand length, leg length, ham length, wrist perimeter) and meat cuts, higher Dorsal Fat Thickness (DFT) and Intramuscular Fat (IMF) levels, but no difference was found in the hot carcass yields (HCY). Differences in the colour parameters and several minerals (Ca, Mg, K and Na) were also due to the different slaughter weights. The rearing system had an influence on the HCY (it is higher in the outdoor system), on many carcass parameters, on meat the ultimate pH (it is higher for animals reared indoors) and on colour (this is variable). It also affected the levels of many minerals with the levels of Mg, P and K being higher for animals reared outdoors, whereas the Fe, Cu and Zn content were higher in the animals reared indoors. DFT and IMF levels were not influenced by the rearing system.     

武定鸡和狄高鸡杂交F1代体尺性状与屠体性能分析

为促进武定鸡的选育,选取武定鸡和狄高鸡进行杂交,分析其杂交F1代的体尺性状与屠体性能,并进行相关性分析和多元回归分析。结果:F1代公鸡体尺性状表型值均高于母鸡,且体斜长、胸宽、龙骨长、髋骨宽、胫长、胫围差异极显著(P<0.01);F1代公鸡除了胸肌率极显著低于母鸡外(P<0.01),其余屠体性能均极显著高于母鸡(P<0.01)。F1代公、母鸡的体斜长、胸宽、胸深、龙骨长、髋骨宽、胫围均高于武定鸡;F1代公鸡屠体性能均高于武定鸡公鸡,其中半净膛率差异显著(P<0.05),活重、屠体重、屠宰率、全净膛率、胸肌率、腿肌率差异极显著(P<0.01);F1代母鸡的活重、屠体重极显著高于武定鸡母鸡(P<0.01),胸肌率、腿肌率显著高于武定鸡母鸡(P<0.05)。F1代屠宰性能间有21个极显著正相关(P<0.01),体尺性状间有14个极显著正相关(P<0.01),体尺性状与屠宰性能间有45个极显著正相关(P<0.01)。同时根据F1代体尺性状建立了预测活重、屠体重、半净膛重、全净膛重、胸肌重、腿肌重、翅重的回归方程。     

Effects of supplementary concentrate level in winter, and subsequent finishing on pasture or indoors, on performance and carcass traits of Holstein–Friesian, Aberdeen Angus × Holstein–Friesian and Belgian Blue × Holstein–Friesian steers

Pure bred Holstein–Friesian (FR) and beef breed × FR male calves are used for beef production in Ireland. Beef breeds used for crossbreeding on FR cows include Aberdeen Angus (AA) and Belgian Blue (BB) which represent extremes in terms of maturity. The objective of this study was to compare spring-born steers of FR, AA and BB breed types, offered two feeding levels in their second winter, and subsequently finished on pasture or on a high concentrate diet indoors. Seventy-two steers (24 per breed type) were managed together to the end of their second grazing season. They were then blocked on weight within breed type and assigned to a 3 (FR, AA and BB breed types) × 2 (winter feeding levels) × 2 (finishing systems) factorial experiment. The two winter feeding levels were grass silage ad libitum plus mean daily concentrate levels of 0.91 (L) or 4.0 (H) kg dry matter for 113 days. The two finishing systems were pasture or concentrates ad libitum for a mean period of 94 days. Mean slaughter and carcass weights for FR, AA and BB were 634, 644 and 642 (s.e. 8.1), and 313, 326 and 340 (s.e. 4.7) kg, respectively. Other than bone proportion which was lower for AA, there were few differences in ribs joint composition or in m. longissimus chemical composition between FR and AA. BB had less fat and more muscle in the ribs joint, and more moisture and protein, and less lipid in m. longissimus than both FR and AA. Compared with L, the H winter feeding level increased slaughter weight and carcass weight by 24 and 15 kg, respectively. Indoor finished animals were 63 kg live weight and 39 kg carcass weight heavier than those finished at pasture. They also had more fat and less muscle and bone in the ribs joint and more lipid and less moisture in m. longissimus. It is concluded that except for BB finished at pasture all carcasses were commercially acceptable. Despite the excellent finishing performance on concentrates, this system is not profitable at current concentrate and beef prices.     

Beef breed comparisons in the U.K.Comparison de races bovines à viande au Royaume UniVergleiche zwischen den Fleischrinderrassen im Vereinigten Königreich

The main results from beef breed comparisons carried out in the United Kingdom during the past 15 years are reviewed. Comprehensive information is now available from the Meat and Livestock Commission's Beef Breed Evaluation programme, complemented by the results from several smaller trials evaluating imported breeds.In most trials, breeds have been compared at similar levels of carcass subcutaneous fat percentage estimated in different ways (equal SF). The sire breeds with larger adult body size were generally slower maturing, taking longer to reach the equal fatness slaughter point; they also grew faster. They ate more food which tended to balance the extra output, resulting in a range of only 10% in feed cost per unit live weight gain. Hereford crosses had consistently high feed efficiencies across the trials. Limousin crosses followed by Aberdeen Angus, Charolais and Sussex crosses had the highest carcass meat percentages and Canadian Holsteins the lowest: the range at equal SF was four percentage units. Continental breed crosses had a marginal advantage in the proportion of their total meat occurring in the higher-priced cuts.     

Inbreeding effects on postweaning production traits, conformation, and calving performance in Irish beef cattle

The objective of this study was to quantify the effect of inbreeding on carcass quality, growth rate, live conformation measures, and calving performance in purebred populations of Charolais, Limousin, Simmental, Hereford, and Angus beef cattle using data from Irish commercial and pedigree herds. Variables analyzed are reflective of commercial farming practices. Inbreeding was included in a linear mixed model as either a class variable or a linear continuous variable. Nonlinear effects were nonsignificant across all traits. Inbred animals had decreased carcass weight and less carcass fat. The effects of inbreeding were more pronounced in the British beef breeds. Effects for carcass weight ranged from -0.87 kg (Charolais) to -1.90 kg (Hereford) per 1% increase in inbreeding. Inbred Charolais and Hereford animals were younger at slaughter by 3 and 5 d, respectively, per percentage of increase in inbreeding, whereas the effect of inbreeding on age at slaughter differed significantly with animal sex in the Limousin and Angus breeds. Inbred Limousin and Angus heifers were younger at slaughter by 5 and 7 d, respectively, per percentage of increase in inbreeding. Continental animals were more affected by inbreeding for live muscling and skeletal conformational measurements than the British breeds; inbred animals were smaller and narrower with poorer developed muscle. Calf inbreeding significantly affected perinatal mortality in Charolais, Simmental, and Hereford animals. The effects were dependent upon dam parity and calf sex; however, where significant, the association was always unfavorable. Dam inbreeding significantly affected perinatal mortality in Limousin and Hereford animals. Effects differed by parity in Limousins. Inbred first-parity Angus dams had a greater incidence of dystocia. Although the effects of inbreeding were some-times significant, they were small and are unlikely to make a large financial effect on commercial beef production in Ireland.     

肉用禽育种中应使用的主要屠宰性状指标的探讨

通过对不同周龄、品种的肉鸡、肉鸭屠宰数据进行分析,发现体重、屠宰重、全净膛重、半净膛重、胴体重这几个指标之间呈高度相关(R＞0.94,P＜0.0001),说明可以把这几个指标合并为一个指标,考虑到育种公司测定的实际需求,建议用屠宰重代替全净膛重、半净膛重.由于腿肌重与腿重呈显著相关,用腿重来代替腿肌重,可以大幅度简化育种工作,提高育种效率.本研究认为可以用宰前体重、腿重、胸肌重、腹脂重作为肉用禽屠宰测定的主要指标,为了计算相关的率,可以考虑测量屠宰重指标.     

Genetic parameters for EUROP carcass traits within different groups of cattle in Ireland

The first objective of this study was to test the ability of systems of weighing and classifying bovine carcasses used in commercial abattoirs in Ireland to provide information that can be used for the purposes of genetic evaluation of carcass weight, carcass fatness class, and carcass conformation class. Secondly, the study aimed to test whether genetic and phenotypic variances differed by breed of sire. Variance components for carcass traits were estimated for crosses between dairy cows and 8 breeds of sire commonly found in the Irish cattle population. These 8 breeds were Aberdeen Angus, Belgian Blue, Charolais, Friesian, Hereford, Holstein, Limousin, and Simmental. A multivariate animal model was used to estimate genetic parameters within the Holstein sire breed group. Univariate analyses were used to estimate variance components for the remaining 7 sire breed groups. Multivariate sire models were used to formally test differences in genetic variances in sire breed groups. Field data on 64,443 animals, which were slaughtered in commercial abattoirs between the ages of 300 and 875 d, were analyzed in 8 analyses. Carcass fat class and carcass conformation class were measured using the European Union beef carcass classification system (EUROP) scale. For all 3 traits, the sire breed group with the greatest genetic variance had a value of more than 8 times the sire breed group with least genetic variance. Heritabilities ranged from zero to moderate for carcass fatness class (0.00 to 0.40), from low to moderate for carcass conformation class (0.04 to 0.36), and from low to high for carcass weight (0.06 to 0.65). Carcass weight was the most heritable (0.26) of the 3 traits. Carcass conformation class and carcass fatness class were equally heritable (0.17). Genetic and phenotypic correlations were all positive in the Holstein sire breed group. The genetic correlations varied from 0.11 for the relationship between carcass weight and carcass fatness class to 0.44 for the relationship between carcass conformation class and carcass fatness class. Carcass weight and classification data collected in Irish abattoirs are useful for the purposes of genetic evaluation for beef traits of Irish cattle. There were significantly different variance components across the sire breed groups.     

浙江省主要鹅种体重、体尺及屠宰性能比较分析

对浙江省现有主要鹅种的体重、体尺及屠宰性能进行了比较分析,并根据各品种的表型性状值进行了聚类分析。结果表明：不同鹅种间在活重、胸深、胸宽、骨盆宽、胫长、胫围、体斜长、龙骨长、半潜水长、屠宰率、半净膛率、全净膛率、腹脂率、胸肌率和腿肌率等指标上均存在明显的差异,同一鹅种体尺、体重和屠宰性能在性别之间的差异也较明显;依据鹅体尺、体重和屠体性状等表型性状值进行品种间聚类分析,其聚类结果与鹅体重和体尺表现出较高的一致性,5个品种可大致分为3类,太湖鹅和江山白鹅为一类,浙东白鹅和朗德鹅为一类,永康灰鹅独立为一类。     

The use of multivariate analysis to characterize carcass and meat quality of goat kids protected by the PGI “Cabrito de Barroso”

Fifty five suckling kids from three genotypes and two sexes protected by the PGI “Cabrito de Barroso” European quality label were used in this experiment. Carcass quality was assessed using indices from carcass measurements, dressing percentages, refrigerated losses, higher priced joints proportion and tissue composition of the carcass. Meat pH, colour, total pigment, fat, dry matter, collagen determinations (total and soluble), cooking losses and shear force estimated in longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used to characterize meat quality. Principal component (PC) analysis was performed in order to examine carcass quality traits (n = 16) and meat quality (n = 16) traits. The five first principal components (PCs) explained about 86% of the total variability for carcass quality and 75% of the total variability for meat quality. Compactness indices of carcass and leg, carcass weight and subcutaneous fat were the most effective variables for the PC1, whereas the higher priced joints proportion, muscle proportions of the higher priced joints and of the carcass and the muscle and bone ratio were useful to define the PC2. The first PC of the meat quality parameters was characterized by colour traits (L, b, a, C, H and total pigment) whereas collagen determinations (total collagen and collagen solubility) defined the second PC. When the carcass quality data were projected on the plane defined by the first two PCs, two separate groups of points appeared, corresponding to the animals with slaughter live weight higher or lower than 10 kg. The distribution of the meat quality data on the plane defined by the first two PCs allowed the identification of two separate groups, corresponding to the muscles GB and LTL. The differences between genotypes tend to be small and related to slaughter live weight, which implies certain constancy in carcass and meat quality of the PGI “Cabrito de Barroso”.     

Additive and nonadditive differences in postweaning growth and carcass characteristics of Devon, Hereford, and reciprocal-cross steers.

Postweaning growth and carcass characters of 110 steers from a complete two-breed diallel of the Devon and Hereford breeds were examined under two environments. Additive and nonadditive effects were estimated using linear contrasts for several growth and carcass traits. Steers from each of the four breed groups were grown postweaning to slaughter in high- and low-nutrition environments. Weights were recorded every 2 mo. At slaughter, hot carcass weight, longissimus muscle area, kidney and channel fat, and subcutaneous fat at nine sites were measured. Heterosis for postweaning growth rate was 3.9% (P less than .01) and for slaughter weight 5.0% (P less than .01). Within the low-nutrition environment during periods of slow and fast growth, the Devons and Herefords performed differently. The growth rate of the steers differed in the two environments; however, heterosis for slaughter weight was of the same magnitude in both environments. No differences existed between the straightbreds or between the reciprocal crosses for slaughter weight. Crossbred carcasses were 7.4% heavier (P less than .01) than the straightbred carcasses; however, this effect was removed after adjustment for differences in slaughter weight. Heterosis for longissimus muscle area and carcass fatness were not significant after adjusting for carcass weight. Additive differences occurred for carcass traits. Devon carcasses had more kidney and channel fat (P less than .05) at a constant hot carcass weight and differences occurred in the partitioning of fat within the subcutaneous depot. No significant maternal effects were observed for the carcass traits measured. Crossbreeding increased carcass weight without altering composition, and relative performance was not affected by the diverse environments.     

张掖肉牛屠宰性能和肉质评定报告

[目的]通过屠宰分析和测定评价,明确张掖肉牛的屠宰性能和肉质风味,作为依据制定下一阶段的选育目标和选配方案。[方法]选择核心育种场育肥牛,检疫后定点集中屠宰测定分析;分割排酸取样,真空包装不同部位肉样带北京试验室根据相应的测定标准进行肉质评定。[结果]张掖肉牛公牛育肥至22.4月龄屠宰,活重、胴体重分别达635.4 kg,371.4 kg,产净肉303.66 kg;屠宰率、净肉率和胴体产肉率分别达58.48%,47.8%和81.76%;胴体脂肪覆盖度良好,肉色和脂肪颜色达到日本胴体分级标准中较高级别。牛肉肉质细嫩,高蛋白,低脂肪,但大理石花纹欠缺。熟肉制品风味独特,多汁性良好,与北京市场销售西门塔牛肉相比,具有较高的适口性和营养价值。[结论]张掖肉牛品种改良、培育成效显著,生产水平达到肉用牛标准,肉质风味能够满足目前的市场需求;若开拓高端牛肉市场,需着力大理石花纹的培育。     

Bovine metacarpal and metatarsal dimensions: Comparison of aberdeen—Angus and charolais steers slaughtered at three percentages of mature cow weight

Fifty-six Aberdeen—Angus (Angus) and 56 Charolais steers were used in a 2 (diet energy levels) × 4 (slaughter weights) × 2 (breeds) factorial experiment. Live slaughter weight groups within each breed were initial, 86 (light), 100 (middle) or 114% (heavy) of average mature cow weight (Angus dams, 467 kg; Charolais dams, 612 kg). Therefore, Angus were slaughtered at 408, 476 or 544 kg and Charolais at 526, 612 or 699 kg. Live, carcass and metacarpal and metatarsal traits were obtained. There were no important effects of diet (2.72 vs. 2.96 Meal metabolizable energy/kg of dry matter). Breed affected (P < 0.01) live body measurements in each slaughter weight group except in initial groups. Within initial groups, breed affected (P < 0.01) live fore- and rear-cannon lengths and wither height. Mean limb-bone weight, expressed as a percentage of live weight, was greater for Charolais than for Angus in each weight group. Bone length increases ceased within Angus between initial- and light-weight slaughter endpoints, but ceased in Charolais between light and heavy groups. Bone area and circumference increased through most weight increments for both breeds, confirming that appositional bone growth continues after length increases cease. Bone specific gravity was maximized in the middle-weight Angus, but increased (P < 0.01) between middle and heavy Charolais. Generally, these results indicate that bone growth subsides earlier and ossification is more advanced in Angus than in Charolais if both breeds are slaughtered at the same percentages of mature weight.