Pre-slaughter Live Weight Research Articles

Estimação pelo método Bayesiano de parâmetros genéticos de peso vivo e características de carcaça em avestruzes

Com o objetivo de estimar parâmetros genéticos de características de desempenho e carcaça de avestruzes criados comercialmente, foi utilizado o método Bayesiano, por meio do algoritmo amostrador de Gibbs, disponível no programa MTGSAM (Multiple Trait Gibbs Sampling for Animal Models). Foram estimadas as herdabilidades e correlações genéticas para: peso vivo ao nascer (PN); peso vivo corrigido aos 190 dias (P190) e aos 360 dias (P360) de idade; peso vivo pré-abate (PVO); perda de peso durante o transporte e jejum (PTA); peso de carcaça (PCA); e rendimento de carcaça (RCA). As herdabilidades respectivas foram 0,11; 0,12; 0,33; 0,05; 0,04; 0,20; 0,05. Para as correlações, foram encontrados os valores de -0,11 entre rendimento de carcaça e peso ao nascer; 0,84 e 0,68 para peso de carcaça com peso aos 190 dias e peso de carcaça com peso aos 360 dias; 0,61 e 0,33 para rendimento de carcaça com peso aos 190 dias e rendimento de carcaça com peso aos 360 dias. Não é viável selecionar para peso ao nascer ou para rendimento de carcaça como é para peso aos 360 dias de idade e peso de carcaça. A seleção para peso aos 360 dias de idade pode melhorar o peso da carcaça, ao passo que a seleção para peso aos 190 dias pode aumentar o rendimento de carcaça.

CARCASS COMPOSITION AND MEAT CHARACTERISTIC OF MALE AND FEMALE RABBITS

A study was carried out on the yield, carcass composition and characteristics of meat of 11 male and 11 female rabbits (F1 0 Californian x Cj> New Zealand). For 77 days the rabbits were kept under identical conditions and were fed with compound feed containing 18% crude protein. An average pre-slaughter live weight of the males of 2,462 ±(O, 15) g and 2,472±(QJ1l g of the females was achieved during the fattening period. The average participation of the clean carcass with and without the head compared to the live mass before slaughtering was 55.76±(O,22)% and 50.77±(O,20)% for the males, and 55.92±(0.24)% and 51.52±(0.19)% for the females. Compared to the mass of the clean carcass with head on of the female rabbits the pelvic-thigh part participated with 30.67%, the flank part with 29.04%, the forelegs with 21.94% and the neck-breast part with 18.35%. The participation of the parts from male rab bits was as follows: the pelvic-thigh part 30.52%, the flank part 28.52%, the forelegs 21.88% and the neck-breast part 19.08%. The participation of the muscle tissue in the mass of the clean carcass without the head was 76.45±(2.18)% for the males and 75. 70±(2.17)% for the females. KnIO'lOBM AYMM: 3aVill~, KnaH~4eH CbCTaB, Meco,QaViHa xapaKTep~CT~Ka, lKMBO Terno.

Management of young goats during prolonged fasting affects carcass characteristics but not pre-slaughter liveweight or cortisol

Effects of pre-slaughter management (72 h continual fasting; 24 h feeding within 72 h fasting; 24 h feeding plus 6 h additional transport within 72 h fasting) and of water availability, gender, weaning 3 weeks before slaughter, initial liveweight (LW) and body condition score (CS) on LW, plasma cortisol and carcass characteristics were studied in young goats. The goats (n = 229) were ~16 weeks of age, with a mean ± s.d. LW of 13.7 ± 2.4 kg. Pre-slaughter treatment did not significantly affect LW or carcass weight at slaughter, but goats fed within the fasting period had lighter-coloured meat compared with the continually fasted goats and the goats fed and transported during the fasting period. Interactions between fasting treatment and gender were evident for hot carcass weight (HCW), retail yield (kg) and dress (% pre-fasting LW). Fasting treatment also interacted with water availability for HCW and with weaning status for GR (12th rib, 110 mm from mid-line) tissue depth. Interactions were evident between gender and water availability for LW at slaughter, and between gender and weaning status for retail yield (% HCW). Weaning status interacted with pre-fasting LW to influence LW at slaughter, and fasting treatment interacted with pre-fasting body CS to influence dress (% pre-slaughter LW). The effects of gender, weaning status, water availability, initial LW and CS on the pre-slaughter LW and carcass characteristics were generally consistent with our previous findings on time off feed. The results show benefits of providing high-quality feed and water and of minimising transport of goat kids during prolonged pre-slaughter fasting. They provide additional information for estimation of carcass characteristics of young goats to be marketed for meat and to aid in the further development of welfare standards for goats. Further research on interactions between gender and pre-slaughter management factors that influence goat carcass characteristics and meat quality is warranted.

Slaughter characteristics of Menz and Horro sheep

Data from 454 Menz and Horro male sheep at Debre Berhan Research Station, Ethiopia, were evaluated for slaughter characteristics. Rams were born from October 1992 to July 1996 and reared together from birth to slaughter at about 17 months of age. Pre-slaughter live weight (PSW) was about 25 kg, while carcass weight (CW) was about 10 kg in both breeds. Empty body weight was significantly higher in the Menz breed than the Horro breed (20.4 kg versus 19.9 kg). The pooled weight of edible non-carcass components in the Menz and Horro sheep was 4.3 and 4.6 kg, respectively. The combined weight of dissected tail and rump fat in the two breeds was about 0.7 kg and 7% of CW. Weights of carcass fat, lean and bone were about 0.9, 6.0 and 2.3 kg, respectively, in the Menz breed and 0.6, 5.9 and 2.5 kg, respectively, in the Horro breed. Fat, lean and bone of the carcass represented about 9, 60 and 23%, respectively, in the Menz and 6, 59 and 25%, respectively, in the Horro. Lean:bone ratio was significantly higher in the Menz than Horro sheep (2.7 versus 2.4). PSW, CW and weights of carcass lean, fat and bone were heritable (0.31–0.51). Heritabilities for carcass lean, fat and bone proportions and lean:bone ratio were estimated at 0.05, 0.49, 0.29 and 0.33, respectively. Genetic correlations among PSW, CW and lean weight were significant (0.83–0.95) indicating selection for PSW should result in a correlated improvement of CW and carcass lean weight. Selection may be beneficial in improving lean:bone ratio, carcass fat and bone proportions in the breeds studied.

Genetic parameters for meat quality and carcass traits and their correlation with wool traits in Australian Merino sheep

Estimates of genetic parameters for carcass traits in Merino sheep are presented, including muscle pH and colour, which are indicators of meat quality. The inclusion of these in the parameter set for genetic evaluation will provide the basis for more accurate estimated breeding values and the design of better breeding programs for improving meat traits in straightbred Merino sheep and crossbred lamb production. Data from 1045, nineteen-month-old Merino rams, the progeny of 125 sires from 3 strains that are representative of the industry, were used. Heritability and genetic correlations were estimated by fitting an animal model using a REML procedure in univariate and multivariate analyses. The traits included fasted pre-slaughter liveweight; dressing %; carcass tissue depth at the GR site (FATGR); fat depth at the C site (FATC); eye muscle depth (EMD), width (EMW), and area (EMA); ultimate pH and colour (L*, a*, b*) of the eye muscle. Multivariate analyses were used to estimate genetic correlations among meat traits and between wool traits (clean wool weight and mean fibre diameter) and selected carcass and meat traits. Estimates of heritability were: liveweight 0.51 (±0.10), dressing % 0.39 (±0.10), FATGR 0.33 (±0.09), FATC 0.20 (±0.08), EMD 0.27 (±0.08), EMW 0.15 (±0.07), EMA 0.23 (±0.08), muscle pH 0.27 (±0.09), and 0.14 (±0.07), 0.02 (±0.06), and 0.04 (±0.06) for the meat colour measurements L*, a*, and b* respectively. There was a favourable genetic correlation between muscle pH and colour L* of –0.56 (±0.23). There were also significant genetic correlations between wool weight and FATGR (–0.34 ± 0.16) and between mean fibre diameter and muscle colour L* (–0.66 ± 0.27). The study indicates that there is genetic variation for carcass traits, including indicators of meat quality, with scope for selection to improve meat production and quality in Merino sheep.

Body composition and adipose tissue accretion in lambs passively immunised against adipose tissue

Thirty-eight cross-bred wether lambs, initial liveweight 35.21±0.75 kg were used to evaluate the effects on growth and carcass composition of passive immunisation with anti-ovine adipose plasma membrane immunoglobulin G (IgG). Antibodies were raised in donkeys by active immunisation with sheep adipocyte membrane protein in Freund’s complete adjuvant followed by boosting at 3, 5 and 15 weeks and subsequently at 4-month intervals with membrane protein in Freund’s incomplete adjuvant. An IgG fraction was prepared from pooled serum by ammonium sulphate precipitation and dialysis. Ten lambs were slaughtered and the remaining lambs ( n=14/group) were injected subcutaneously with 80 ml of IgG from immunised (treated) or non-immunised donkeys (control) on 4 consecutive days at the beginning of the study. Following a 91-day test period the animals were slaughtered, the weights of internal organs and fat depots recorded and carcass composition determined by dissection. Treatment did not affect preslaughter liveweight (Control=47.8 kg, Treated=47.4 kg) or carcass weight (Control=25.9 kg, Treated=24.7 kg). Liver weight tended to be increased ( P=0.07) by treatment (from 751 to 905 g), while the weights of other organs were not affected. The weights of the omentum and kidney/channel fat depots were reduced ( P<0.05) by 18.1 and 27.7%, respectively, by treatment. Treatment decreased the weight of dissectable subcutaneous fat (from 2.7 to 2.4 kg, P<0.1), dissectable intermuscular fat (from 2.9 to 2.3 kg, P<0.05) and total dissectable fat (from 5.6 to 4.7 kg, P<0.05) without a decrease in dissectable meat. Daily adipose tissue accretion was decreased by 25% approximately for omentum, intermuscular, subcutaneous and total carcass fat and by 37% for kidney/channel fat by treatment. Treatment resulted in an acute decrease in plasma glucose and insulin concentrations, an acute increase in non-esterified fatty acid and β-hydroxybutyrate concentrations and a chronic increase in insulin concentration. It is concluded that passive immunisation of lambs with anti-ovine adipose plasma membrane IgG can reduce body fatness without decreasing lean meat accretion.

A comparison of growth and carcass traits in Scottish Blackface lambs sired by genetically lean or fat rams

AbstractAn experimental programme was initiated in 1990 to investigate the consequences of selection for reduced fatness in hill sheep and to estimate genetic parameters for carcass traits in the same class of animal. Thirty-two progeny groups of lambs were born as a result of mating Scottish Blackface rams to ewes of the same breed on two Scottish Agricultural College hill farms in 1991 and 1992. Sires were from two divergent selection lines for subcutaneous back fat depth and were selected under ad libitum feeding conditions on an index combining live weight and ultrasonic fat depth at 20 weeks of age. The index was designed to alter body composition but not body weight. Weaned male progeny (reared extensively) were brought together from both farms in August of each year, reared on grass and finished for slaughter on swedes at a target condition score of 3. Measurements taken at weaning were: live weight, average ultrasonic measurements of average subcutaneous fat depth and muscle depth. At slaughter, traits measured were: pre-slaughter live weight, pre-slaughter condition score, age at slaughter, cold carcass weight, killing-out proportion, Meat and Livestock Commission (MLC) fat class and MLC conformation class. Side and shoulder dissections were made on proportionally 0·2 and 0·8 of lambs respectively and lean tissue, subcutaneous fat, intermuscular fat and bone were measured. Comparisons were made between the two genetic lines and genetic parameters were estimated from data adjusted to three different ‘end-points’: constant dissected subcutaneous fat weight, constant age at slaughter and constant cold carcass weight. Moderate to low heritability estimates were obtained for most traits: pre-slaughter live weight = 0·36, cold carcass weight = 0·39, fat class = 0·13, conformation class = 0·09, lean weight = 0·27, bone weight = 0·36 (constant subcutaneous fatness), intermuscular fat = 0·20, subcutaneous fat = 0·20 (constant cold carcass weight). Correlations between ultrasonic measurements at weaning, and slaughter and dissected carcass components were moderate to weak. However, there is sufficient genetic variation in the carcass traits to warrant inclusion in breeding goals for hill sheep. The results also show that genetic differences obtained by selection under intensive rearing conditions for divergent fatness are also seen in progeny reared under extensive (hill) conditions.

Meat quality of cryptorchid lambs grazing either dryland or irrigated perennial pasture with some silage supplementation

The meat quality of lambs grazed on perennial pasture (ryegrass Lolium perenne, cocksfoot, Dactylis glomerata and white clover Trifolium repens) was examined in three treatments; group 1 (S) lambs were grazed on dryland pasture for 30 days and then offered a supplement of pasture silage ad libitum until slaughter, 30 days later ( n = 21). Lambs in group 2 (P) were grazed on dryland pasture throughout ( n = 28) and those in group 3 (IP) on irrigated pasture ( n = 28). Lambs in group IP had a significantly ( p < 0.001) heavier pre-slaughter liveweight and hot carcass weight than lambs in the other two groups. There was no significant difference ( p < 0.05) infatscore between groups or in GR when adjusted to a common carcass weight. For cold carcass weight (reduced sample) IP lambs were still significantly heavier than those from group P, but no different to those from group S ( n = 15, 15 and 10, respectively). There was no significant difference between groups for measures of fatness or for m. longissimus thoracis et lumborum (LL) area when adjusted to a common carcass weight of 23.6 kg. There was a significant difference between ( p < 0.001) treatments for pH, group P carcasses having higher pH values for the LL muscle, with no treatment effect on m. semimembranosus (SM) pH. Differences between groups for meat colour values ( L ∗, a ∗, b ∗ ) showed no consistent trend and there was no significant difference ( p > 0.05) between groups in tenderness of the LL and SM muscles as indicated by shear force values. Aroma of the loin meat from pasture-fed lambs (P) was considered significantly ( p < 0.05) stronger than from lambs in groups S and IP ( n = 6, all groups) and the flavour of samples from lambs in group P was significantly ( p < 0.05) stronger than from lambs in group IP. Overall there was no significant ( p < 0.05) difference in acceptability between groups. The results indicate that consumers would be unlikely to detect the differences identified by the panel and that pasture silage will not have an adverse effect on lamb eating quality.

Carcass and meat quality of second-cross cryptorchid lambs grazed on chicory (Cichorium intybus) or lucerne (Medicago sativa)

The meat quality of cross-bred cryptorchid lambs (6 months old) that had been grazed on chicory (Cichorium intybus; n = 20) or lucerne (Medicago sativa; n = 20) for 8 weeks preslaughter was studied. Unfasted preslaughter liveweight (range 42.5-51.5 kg) was not affected (P&gt;0.05) by treatment. There was no difference (P&gt;0.05) between groups for age at slaughter, hot carcass weight, or measures of fatness GR and Fat C (fat depth over longissimus thoracis et lumborum) when adjusted to a common carcass weight of 21.9 kg. Lucerne-fed lambs were, however, significantly (P&lt;0.05) fatter at the 5th rib. There was no significant (P&gt;0.05) difference between groups for pH, colour values (where L* indicates relative lightness, a* relative redness, b* relative yellowness), Warner-Bratzler shear values, or cooking loss. There was no significant (P&gt;0.05) difference between groups for mean fat colour score or for the distribution of the scores. The b* values for subcutaneous fat tended (P = 0.06) to be greater for lucerne-fed lambs. A comparison of the mean values for aroma and flavour of the longissimus thoracis et lumborum showed no significant (P&gt;0.05) difference between groups and no difference in overall acceptability. Finishing lambs on the chicory cultivar used in this experiment did not adversely affect meat quality and did not result in fatter carcasses than lucerne-fed lambs.

Foot scores of cattle 2. Relationships among measurements of feet from slaughtered steers from eight sire groups

Abstract Objective linear measurements were taken at slaughter on the front and rear feet excised from 87 Angus-sired steers by known sires and dams. Generally, means for front foot traits were similar to those for rear feet, including a difference of only 2.0° in angle of front v. rear foot. The repeatability of objectively measured traits was high (>0.76). Correlations between measures on adjacent digits were high (0.54 – 0.88), as were most correlations between data from front and rear feet. Coefficients of variation for pre-slaughter liveweight, hot-carcass weight, hoof horn length, and angle (of hoof away from the vertical) ranged from 5.9 to 8.00%, for sole length (measured underneath the hoof) 4.8 to 5.8%, and for foot circumference 2.8%. Sire group effects were the only significant source of variation for the 14 foot traits. Principal component analysis of the variance-covariance matrix showed that 85, 7, and 3% of the variation was accounted for by the first three components, mainly describing slaughter liveweight, hoof horn lengths, and sole (i.e., underside) lengths respectively. Heavier cattle had larger hooves, with an angle indicating 'feet positioned closer to the vertical than for average~ eight animals. One sire group was of particular mterest because the herd owners thought the sire himself was unsuitable for use because of poor feet. Small but significant structural effects were found in his progeny group. His progeny were the most deviant for only one trait (length of sole on rear feet, as measured from below), and that was in a negative direction, which was favourable.

A note on the Charolais and Murray Grey as terminal sire breeds

ABSTRACTA comparison was made of the carcass characteristics of 73 Charolais-sired and 86 Murray Grey-sired cattle slaughtered at about 20 months of age. Six Charolais and 10 Murray Grey sires were used. At a constant slaughter age (597 days) the Charolais-sired calves had significantly heavier pre-slaughter live weight (36 kg) and carcass weight (24 kg) and significantly less fat over the m. longissimus (2·8 mm), but there was no significant difference in killing-out proportion. In the dissected half-carcass, the Charolais-sired calves had significantly more meat (9·3 kg), more bone (3·5 kg) and less fat (1·9 kg). At a constant carcass weight (233 kg), Charolais-sired calves had significantly more meat (1·8 kg) more bone (1·9 kg) and less fat (3·5 kg) in the dissected side. After making allowance for the higher calf mortality from birth to weaning of Charolais-sired calves (0·041), the advantage in carcass weight was reduced to 13 kg. It is concluded that the Charolais breed is superior to the Murray Grey as a terminal sire.

A comparison of three ultrasonic machines (Danscan, AIDD (NZ) and Body Composition Meter) and subjective fat and conformation scores for predicting chemical composition of live sheep

SUMMARYUltrasonically measured backfat depths and subjective fat and conformation scores taken on 123 Romney ewes were related to the chemical composition of the carcass in trial 1. Fat depths at one position over the eye muscle, determined using ultrasonic machines with a single probe, were similar to the best judge's fat scores at predicting carcass composition after adjustment for pre-slaughter live weight. Fat depths measured from a two-dimensional scan (Danscan) did not predict carcass composition as well as most of the judges' fat scores. Judges' conformation scores failed to improve the prediction of composition after adjustment for live weight and fat score.In trial 2, two ultrasonic machines of the single probe type provided accurate measure of carcass fat depths on both full fleeced and shorn sheep. Ultrasonically measured fat depths would appear to be a useful method for selecting lean breeding stock and for training inexperienced stock judgesto assess fatness of sheep.