Carcass Bone Research Articles

Effects of dietary phosphorus and nitrogen deficiencies on the intake, growth and metabolism of lambs

SUMMARYThe effects of dietary deficiencies of phosphorus (P) and nitrogen (N) were studied in 28 lambs allotted to seven treatments for 18 weeks. The lambs in four treatments were offered roughage-based dietsad libitumcontaining high (H) or low (L) levels of P (4·13 or 0·98 g/kg dry matter (DM)) and N (108 or 68 g crude protein/kg DM). The lambs in the remaining three treatments were fed the same quantities of DM of the HNHP diet as the lambs receiving the three deficient diets (HNLP, LNHP and LNLP). A dietary deficiency of P caused a reduced DM intake and liveweight gain, lower yields of N and DM in carcass muscle and reduced DM, N and P contents of bone. A dietary deficiency of N resulted in reductions in DM intake, liveweight gain, DM digestibility, N balance, and in carcass muscle and bone DM and N. The deficiencies of N and P were not additive in lowering food intake but were additive in reducing the mineralization of the bones. The DM intake of the lambs offered their dietsad libitumwas closely correlated to the log of the plasma inorganic P and urea N concentrations (R =0·72). Feeding lambs with restricted quantities of diet HNHP resulted in higher liveweight gains and DM and N digestibilities than when any of the deficient diets were offered. Measurement of the N content of the lambs by a neutron capture gamma ray analysis technique showed that the changes were occurring progressively over the experimental period. The P content of the metatarsal bone, measured by a neutron activation technique, showed progressive changes. Although the faecal endogenous losses of P were related to P intake, high urinary losses were observed in those lambs which had their food intake limited by low dietary N alone, or had their food intakes restricted. The total endogenous P losses of the lambs were most closely dependent upon the DM intake and plasma inorganic P together. The efficiency of P absorption was high (> 0·75) in all lambs except for those given the HNHP dietad libitum. The glucose entry rate was reduced in the lambs offered diets deficient in either N or P. Mechanisms by which the N and P deficiencies reduce DM intake are discussed.

A comparison of growth, food efficiency and carcass characteristics of single and twin beef calves derived by embryo transfer

AbstractAn experiment was designed to examine the interaction between birth status and plane of nutrition of calves in relation to postnatal and lifetime performance. The experiment was a 2 × 2 × 2 factorial arrangement of birth status (single and twin), plane of nutrition from birth to 16 weeks (period 1) and plane of nutrition from 16 weeks to slaughter at a mean live weight of 530·4 (s.e. 0·13) kg (period 2). The planes of nutrition were control and low with metabolizable energy (ME) intakes of 32·1 and 21·4 (s.e. 0·46) MJ/day from birth to 16 weeks, and 73·9 and 64·1 (s.e. 0·95) from 16 weeks until slaughter. The birth weights of the single and twin-born calves were 47·2 and 39·7 (s.e. 0·90) kg respectively. There was no interaction between birth status and plane of nutrition in either main period and by 40 weeks of age the live weights of the twin calves were similar to those of the single-born calves. For period 1 plus period 2 the live-weight gains per unit of ME intake were 12·4 and 13·1 (s.e. 0·28) g/Mf for single and twin-born calves respectively. Although twins had slightly poorer carcass conformation and higher proportion of bone in the carcass, the concentrations of saleable meat and high-priced joints in the carcass were similar. Birth status had no effect on the ultimate pH of muscle. It is concluded that viable twins have similar beef producing potential to single-born calves.The control and low planes of nutrition imposed during the periods from birth to 16 weeks and 16 weeks to slaughter produced live-weight gains of 822 and 573 (s.e. 31·0) g/day, and 857 and 690 (s.e. 12·6) g/day respectively. Calves which had been on the low plane during the initial period had a compensation index of 0·30 by 64 weeks of age. Carcass measurements were not affected by the plane of nutrition during either period. Steers grew faster than heifers, had lower area o/m. longissimus dorsi but less separable fat and more bone in the forerib joint than heifers at equal carcass weight.

Comparison of Friesian, Canadian Hereford × Friesian and Simmental × Friesian steers for growth and carcass composition

AbstractOne hundred and twenty spring-born steers comprised of 40 Friesians (FR), 40 Canadian Hereford × Friesians (HF) and 40 Simmental × Friesians (SM) were reared together from shortly after birth to slaughter after a mean period of 740 days. During the finishing winter there was a 3 (breed types) × 2 (3 and 6 kg supplementary concentrates per head daily with grass silage ad libitum) × 2 (222- and 225-day finishing periods) factorial arrangement of treatments. One side from each of 96 carcasses (eight per treatment) was completely separated into bone, muscle, intermuscular fat and subcutaneous fat and a 10th rib sample of m. longissimus was chemically analysed.Carcass weights per day of age and carcass weights were 404, 433 and 449 (s.e. 4·6) g and 301, 320 and 330 (s.e. 3·4) kg for FR, HF and SM, respectively. Corresponding proportions of carcass muscle were 602, 577 and 628 (s.e. 4·8) g/kg. FR and HF had similar proportions of their total muscle in the hindquarter, whereas SM had more of their muscle in the hindquarter. M. longissimus lipid concentrations for FR, HF and SM were 36, 39 and 26 (s.e. 1·96) g/kg. Increasing supplementary concentrate level from 3 to 6 kg/day increased side weight by 7 kg, of which proportionately 0·48 was fat. Extending the finishing period from 121 to 225 days increased side weight by 22 kg of which proportionately 0·45 was fat. Both the higher concentrate level and the longer finishing period reduced carcass muscle and bone proportions, and increased carcass fat proportion. Allometric regression coefficients for side muscle, bone and fat weights on side weight were 0·75, 0·51 and 2·13, respectively. It was calculated that FR, HF and SM would have similar carcass fat proportions at approximate carcass weights of 320, 290 and 380 kg, respectively.

Effect of agricultural by-product diets on carcass characteristics of four types of cattle in the feedlot

Five type of formulated diet from agricultural by-products (ABP) were fed to four breedtype of cattle in feedlot. The ABP used are palm kernel cake (PKC), palm press fibre (PPF), palm oil mill effluent (POME), cocoa pod (COP), coffee pulp (COF) and pineapple waste (PAP). The formulated diets are PS (52% PKC, 15% PPF and 30% POME), PF (57% PKC, 20% PPF and 20% POME), PA (2% PKC and 55% PAP), CO (42% PKC and 55% COP) and CF (67% PKC and 30% COF) with 1% urea, 1% NaCl and 1% vitamins premix. The cattle breedtypes are Kedah-Kelantan (KK), Brahman-KK (BK), Hereford-KK (HK) and Sahiwal-Friesian (SF). The result showed that breedtype significantly affect all the carcass characteristic except dressing percentage. Each breedtype has it`s specific carcass characteristics. HK cattle gave high marbling, BK has high % of carcass bone, KK has high % of carcass meat and low % of carcass fat (lean meat type) and SF has high % of carcass fat. Diet-type significantly affect the deposition of fat in the carcass. High moisture diets (PA and CO) produced significantly higher % carcass bone, the lowest % carcass fat and the highest % carcass meat (65.3%). PF, CF, PA and CO diets produced 63.4%, 59.9%, 55.3% and 54.1% carcass meat respectively.

Effect of feeding level, breed and milking potential on body tissues and organs of mature, non-lactating cows

ABSTRACTBody composition was studied in 20 mature, non-pregnant, non-lactating cows from five breeds (Hereford, Aberdeen Angus, Dexter, British Friesian and Jersey) kept on four feeding levels until they attained equilibrium body weights that were proportionately 0·7,0·9,1·1 or 1·3 of their normal adult body weight.Significant breed differences were found in the proportions of body tissues and organs and these were associated with breed differences in lactability (i.e. genetic milking potential adjusted for body size). As a proportion of body weight, intra-abdominal fat, liver, spleen and uterus increased significantly with lactability and hide decreased significantly. Empty gut and gut fill also increased with lactability but not significantly. Liver proportion in dairy breeds was 1·26 times the proportion in beef breeds. Corresponding values for intra-abdominal fat and hide were 1·43 and 0·83.The most dramatic increases with feeding level were in the proportions of subcutaneous fat, both intra-abdominal fat depots, and the udder. All fat depots were completely depleted when body weight decreased to about 0·6 of its normal adult value. Strong decreases occurred in the proportion of muscle, carcass bone and offal. The proportion of empty gut decreased significantly with increased feeding level. Liver, tail, thymus and possibly gut fill were the only traits entirely unaffected by feeding level.The near-constancy of liver proportion at equilibrium implies that the rapid response of the liver to a change in feeding level is eventually matched in magnitude by the slower responses in other tissues and organs, so that the original proportionality of about 1 kg body tissue for each 10 g liver is eventually restored.

Breed and sex differences among equally mature sheep and goats 5. Lipid in dry tissue

ABSTRACTMales and females from Soay, Welsh Mountain, Southdown, Finnish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and a breed of feral goats were slaughtered when proportionately 0·40, 0·52 0·64 or 0·76 of mature live weight. Lipid concentrations in dried tissue were obtained for perirenal fat, omental plus mesenteric fat, subcutaneous fat, carcass muscle plus associated intermuscular fat, carcass bone and offal (pelt, head, feet and organs). Lipid varied from 260 g/kg dry matter (DM) for bone to 968 g/kg for perirenal fat.As animals matured, lipid concentration increased in the dry matter of all tissues except bone, most rapidly in offal and least in intra-abdominal fat. The increases were highly correlated with the associated increases in proportion of dissected fat.Breeds differed significantly in lipid concentration in the DM of all tissues examined. Breeds with a high lipid concentration in DM of one tissue usually had high concentrations in all other tissues. The Oxford Down had the highest concentration, and the Soay and feral goat the lowest. Males had slightly lower concentrations in all tissues except internal fat.As breed size increased, mean lipid concentration (at the same stage of maturity) also increased in the DM of all tissues except bone. These breed regressions were attributed to the sampling of breeds, the smallest breeds being the exceptionally lean Soay and feral goat. Among the domesticated breeds, there were no signficant trends with breed size.

Minerals of carcass soft tissue and bone of serially slaughtered cattle as affected by biological type and management

SummaryMineral concentrations of soft tissue and bone were measured in carcasses from cattle slaughtered serially across a wide weight range. Seventy-four small framed Angus steers and 71 Holstein steers were selected to represent diverse mature types. Cattle were individually fed ad libitumeither a maize grain or maize silage diet, housed inside a barn or in outside pens and slaughtered over five weights within breed. After slaughter, a half-carcass was separated into soft tissue (lean and fat) and bone. Tissues were ground, freeze-dried and K, P, Ca, Mg, Na, Fe, Cu, Zn and Mn were measured. Concentrations of minerals were analysed by covariance analysis, using carcass weight as a covariate.The relationships between carcass weight and concentrations of all soft tissue minerals except Na and Zn were not affected by diet, breed or type of housing. Concentration of Na decreased with increasing carcass weight and at a slower rate in soft tissue of grain-fed cattle than in soft tissue of silage-fed cattle. Concentration of Zn increased with increased carcass weight in Angus, while in Holsteins it decreased. Soft tissue of Angus and Holsteins had similar concentrations of Fe and Mn. Holsteins had higher concentrations of the other minerals in soft tissue than Angus, possibly because they were at an earlier stage of maturity at the same carcass weight. Carcass weight had no effect on K, Ca, Fe or Cu content of soft tissue.Diet influenced concentrations of P, Ca and Na in bone and affected the relationship of bone Fe to carcass weight. Due to their later stage of maturity at the same carcass weight, Angus had less K and more Ca, Na and Zn in bone than Holsteins. Carcass weight had no influence on K, P, Mg, Na, Cu or Mn content of bone.These data provide baseline values for future studies, show that breed mature size differences in mineral concentrations of soft tissue and carcass bone may exist and that diet may influence concentration of soft tissue Na and some bone minerals.

Growth performance and body composition of wether lambs implanted at two different initial live weights with trenbolone acetate combined with oestradiol-17β

AbstractThirty-two Border Leicester ♂ × Scottish Blackface ♀ wether lambs, aged about 5 months, were divided into two groups on the basis of live weight, such that group G1 contained the 16 lightest lambs and group G2 the 16 heaviest. Lambs in group G1 were subdivided equally at random either to be sham-implanted controls (Group C1) or to be implanted with 35 mg trenbolone acetate (TBA) + 5 mg oestradiol-17β (OE) (group T1) at 24 kg initial live weight. The lambs in group G2 were also subdivided into two groups (groups C2 and T2), and similarly treated approximately 1 month later at 37 kg initial live weight. The lambs were offered ad libitum a diet containing an estimated 12·5 MJ metabolizable energy (ME) per kg dry matter (DM) and 140 g/kg DM crude protein. Comparisons were made for the main effects of hormonal treatment and initial live weight. Both hormonal treatment and initial live weight gave increases for DM intake, gut fill, empty body weight, carcass weight and, in the half carcass side weight, weights of dissected lean tissue, bone and intermuscular fat and chemically determined DM, crude protein and lipid. Weights of mm. semitendinosus, longissimus dorsi, supraspinatus and gastrocnemius were also increased due to hormonal treatment and in group G2 lambs compared with those in group G1. When expressed as a proportion of carcass side weight, hormonal treatment effects were not significant for individual muscles and dissected carcass lean, bone and fat and chemically determined lipid and ash. Variable effects on other body components were recorded for both treatments in the absence of any significant interactions. The responses to hormonal treatment were essentially similar in groups G1 and G2. The question is raised as to the contribution of the greater food intake in implanted lambs to the maintenance of fatness in these animals.

Influences of Anabolic Hormone Treatment and Dietary Protein: Energy Ratio on Condition and Muscle Deposition of Rainbow Trout

Abstract The effects of dietary 17a-methyltestosterone (MT) and protein-to-metabolizable energy (P:ME) ratios on the weight gain of individual body components and their relative contribution to the condition factor (K) were examined for juvenile rainbow trout (Salmo gairdneri). Five semipurified isocaloric diets (390 kcal/100 g dry ingredients) containing 80, 100, 120, 140, and 160 mg protein/kcal ME were prepared with and without 2.0 mg MT/kg of diet and fed to 5-g rainbow trout for 8 weeks. At the end of the experiment, fish were weighed and measured, and then dissected or cooked to obtain individual wet weights of the head, fins, skin, muscle, carcass bone, viscera, and rib section. Steroid treatment increased the weight gain of muscle tissue in direct proportion to the increase in body weight gain. Linear bone growth was enhanced with treatment, but the rate of increase did not keep pace with the rate of weight increase of the rest of the body. This accounted for a lowered percentage bone weight gain ...

Bone growth in the indigenous Nigerian pigs as a function of age, sex and body weight

SummaryThe left half carcasses of 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs were dissected in order to study the bone growth between birth and 672 days of age. Total bone weight as well as the weights and lengths of femur, tibia–fibula, humerus and radius–ulna were studied at 16 ages. While bone weights increased between 34 and 45 times from birth to the terminal age range, bone lengths on the average only quadrupled within the same period. Maximum growth in bone weight occurred at 112 days of age whereas bone length attained maximum growth rate at 56 days of age when the body weights had averaged 15·8 and 6·2 kg respectively.Beyond these body weights, the growth rates declined. Although sex differences for total bone weight were not significant, the individual long bones studied exhibited significant sex differences. Highly significant age and sex influences were obtained for the relative bone weights.The growth coefficientsbdetermined for the individual bones and total bone using the logarithmically transformed allometric equationY=oXb, ranged from an average of 0·76 for radius–ulna to O·80 for femur. Pooled values for total carcass bone was 0·84. The values agreed with those reported in literature with side weight as independent variable, and confirm bone to be early developing. Bone lengths were related more to body weight than to chronological age as judged by theR2values. In all the bone traits studied, intact male pigs showed larger values than the castrated male and female pigs.

Lifetime growth and carcass composition of heifers and steers non-implanted or sequentially implanted with anabolic agents

ABSTRACTSixty-four (48 female and 16 male) spring-born Hereford × Friesian calves were used to examine the effects of sex type, heifer slaughter age and implantation with anabolic agents on growth and carcass composition. Non-implanted and implanted heifers were slaughtered after 491, 612 and 731 days and non-implanted and implanted steers (castrated on day 81) were slaughtered after 731 days. Implantation was with 36 mg resorcylic acid lactone (RAL) on days 81 and 171 and RAL plus 300 mg trenbolone acetate on days 395, 491, 583 and 658.Carcass weights of non-implanted and implanted heifers slaughtered at 491, 612 and 731 days were 189 and 206, 218 and 235 and 290 and 326 (s.e.d. 10·1) kg respectively. Carcass lean, bone and fat weights and fat proportion increased with increasing slaughter age but proportions of lean and bone decreased.There was no difference between heifers and steers in growth rate to 395 days but from 395 to 731 days the steers grew faster than the heifers. Non-implanted and implanted steer carcass weights at 731 days were 297 and 355 (s.e.d. 9·5) kg respectively. Steer carcasses had higher lean and bone proportions and a lower fat proportion than heifer carcasses. Implanted animals had heavier carcasses than non-implanted animals and all of the extra carcass weight consisted of lean and bone. The results indicate that non-implanted and implanted heifers and steers had similar lean proportions when the heifers were 31 and 70 kg carcass weight respectively lighter than the steers.

Fat distribution and indices of carcass composition in Coats Island caribou (Rangifer tarandus groenlandicus)

Twenty-seven barren-ground caribou (Rangifer tarandus groenlandicus) carcass sides were dissected on Coats Island, Northwest Territories, Canada, to calibrate indices of dissectible fat, muscle, and bone. Carcass muscle weight was accurately predicted from weight of the gastrocnemius muscle (In (carcass muscle, kg) = −2.791 + 1.071 In (gastrocnemius, g); r2 = 0.98), and carcass bone weight was accurately predicted from weight of the femur (In (carcass bone, kg) = −4.878 + 1.137 In (femur, g); r2 = 0.98). These allometric relationships held for calves and adults and for animals gaining and losing fat. The subcutaneous, intermuscular, pelvic, and internal omental and perirenal fat depots were weighed for each of 23 animals. The intermuscular and subcutaneous depots were largest and subcutaneous fat increasingly predominated at advanced fatness. Total dissectible fat in the five depots was most accurately predicted from depth of back fat and weight of kidney fat (dissectible fat (kg) = −0.178 + 1.058 depth of back fat (cm) + 24.147 kidney fat (kg); r2 = 0.98) and the regression was unaffected by age or condition. Comparison with similar studies suggests that such within-tissue relationships may be valid for all subspecies of Rangifer.

The accretion and distribution of carcass tissues in steers during growth between 9 and 15 months of age

Carcass muscle, fat and bone weights, and distribution in 12 Brahman x Hereford steers between 9 and 15 months of age were obtained by carcass side dissection. The tissue proportions of liveweight and carcass weight at mean age 13 months, and the regression estimates of tissue accretion and distribution were compared. The carcass muscle and bone components of liveweight gain decreased by 18 and 24% respectively, and carcass fat increased by 64% when all tissues were compared to composition at 13 months of age. The tissue components relative to carcass weight gain followed the same pattern. The decrease in muscle and bone growth relative to liveweight gain was greater in the hindquarters. Whereas hindquarter muscle, fat and bone were 530, 570 and 450 g/kg respectively of carcass muscle, fat and bone at the mean age of slaughter, they were 500, 570 and 420 g/kg of the respective carcass tissue accretions between 9 and 15 months. The disproportionate decrease in muscle accretion between the carcass quarters was largely a result of differences in growth among the 26 heaviest carcass muscles.

Developmental Comparisons of Boars and Barrows: II. Body Composition and Bone Development

Differences in total carcass bone, muscle and fat, and linear measurements of the tibia and radius were evaluated in barrows at 105 kg and boars at 105, 118, 132 and 145 kg live body weight. The carcasses of five replicates were physically separated into skin, bone and soft tissues, and the linear measurements of the tibia and radius were obtained on seven replicates. At live weight of 105 kg, boars did not differ significantly in fat-free muscle, but they had 33.2% less fat, 11% greater bone weight and 14% greater skin weight than barrows. At 145 kg, boars had total carcass fat weight comparable with 105-kg barrows. Fat-free muscle, bone and skin weight of boars increased at linear rates of .41, .083 and .104 kg/kg of body weight increase from 105 to 145 kg, respectively. At 105 kg, density and length of the tibia and radius did not differ between boars and barrows. The tibia of boars were heavier than those of barrows at 105 kg, resulting in a greater ratio of tibia weight to length (indirect measure of bone thickness). As boars increased in live weight from 105 to 145 kg, total weight and length of the tibia and radius increased linearly. The ratio of weight to length of the tibia and radius increased during this 40-kg weight gain, indicating that weight of both bones increased at a greater rate than length. These results indicate that boars and barrows have the same weight of total carcass fat when boars are 40 kg heavier than the barrows. The greater bone weight of boar carcasses compared with barrows is due to greater bone thickness.

CARCASS TISSUE YIELD AND DISTRIBUTION IN THREE BIOLOGICAL TYPES OF CATTLE FED GRAIN OR FORAGE-BASED DIETS

One hundred and eighty-nine steers comprising 63 small (S) rotational crossbreds, 66 large (L) rotational crossbreeds and 60 Holsteins (H) were fed either a concentrate diet based on corn silage and high-moisture corn, or a forage diet based on a mixture of corn silage and alfalfa haylage. All steers were fed ad libitum and slaughtered to cover a range in external fatness (0–15 mm subcutaneous fat). Steers were removed from feed 36 h and water 16 h prior to slaughter. The left side of each carcass was separated into depot fat, lean and bone. At the same proportion of subcutaneous fat (63 g/kg carcass), S and L carcasses had greater proportions of carcass lean (P < 0.001), but less fat (P < 0.01) and bone (P < 0.001) than carcasses from H Steers. Small and large carcasses had greater muscle to bone ratios (P < 0.001) than carcasses from H steers. Diet had no effect on lean tissue proportions, but forage feeding increased carcass bone (P < 0.001) and decreased carcass fat (P < 0.01). Forage feeding also resulted in carcasses with lower muscle to bone ratios (P < 0.01) than carcasses produced from grain feeding. Holstein-carcasses had more carcass fat partitioned into the body cavity depot and less into the subcutaneous depot than S and L carcasses, but diet had no effect on fat partitioning. Biological type (S, L or H) and diet were found to have a minor effect on fat distribution. The results are discussed with reference to carcass evaluation of beef and dairy cattle fed diets based on forage or grain. Key words: Biological type, diet, carcass composition, carcass grading

Distribution of Ether Extract, Moisture, Protein and Ash in Dissected Tissues from Ovine Carcasses

Thirty-three sides from ovine carcasses representing a wide range in weight and fatness were dissected into subcutaneous fat (sub fat), intermuscular fat (intermus fat), muscle, flat bones and round bones. Equations to estimate weights of ether extract, moisture, protein and ash in each dissected tissue and equations to estimate weights of dissected tissue in the side were developed to determine how accurately distribution of fat and other carcass components could be predicted. Equations for predicting weight of ether extract in sub fat or weight of total dissected sub fat from a linear fat measurement, ether extract in the side and side weight had low standard errors of estimate and coefficients of determination of .99. Weight of intermus fat and muscle or weight of ether extract in these tissues could also be accurately determined. Ether extract, moisture, protein and ash percentages in sub fat, intermus fat, muscle, flat bones and round bones changed with changes in carcass composition. Ether extract in dissected sub fat and intermus fat increased by about 20 percentage points as carcasses became fatter. Dissected sub fat contained a higher percentage of ether extract than did intermus fat and round bones contained over twice the percentage ether extract of flat bones. Ether extract from muscles, flat bones and round bones of lean carcasses made up about 36% of the total ether extract in the side. Overall, prediction of weight of individual dissected tissues (standard error of estimate, g = 58 to 165) or of their chemical components (standard error of estimate, g = 1 to 86) is possible.

Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 2. Chemical and dissectible body composition

ABSTRACTThe changes in chemical and dissectible body composition from birth to maturity were examined in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. Body composition was examined in 34 mature animals and the maturing patterns for body components calculated using mean values from the mature animals and individual data from 106 immature animals.In the 34 mature animals, strain had no effect on the proportions of chemical and dissected fat, protein and muscle in the body. The weight-plus had greater proportions of ash and carcass bone in the body than the weight-minus animals. Mature rams had lower proportions of chemical and dissected fat and greater proportions of protein, muscle, ash and carcass bone in the body than mature ewes.The weight-minus animals had later maturing patterns for both chemical and dissected fat than the weight-plus animals. Strain had no effect on the maturing patterns for protein and muscle, although both ash and carcass bone were later maturing in the weight-plus, than in the weight-minus animals. Chemical and dissected fat were later maturing in the ewes than in the rams, whereas protein, muscle, ash and carcass bone were earlier maturing in the ewes than in the rams.The weight-minus animals were fatter at the heavier body weights, although there was a trend for the weight-plus animals to be slightly fatter at the lighter body weights. When compared at the same stage of maturity of body weight, strain differences in the proportion of fat in the body declined as the animals matured. Compositional differences between the rams and ewes varied according to the body weight or stage of maturity of body weight at which they were compared.

USDA yield grades and various carcass traits as predictors of carcass composition

Twenty-five carcasses from each of three breedtypes (Brahman, Angus and Brahman × Angus) were physically separated into fat, lean and bone. Several muscles from the round and the femur were used to derive equations to predict carcass composition and muscle-to-bone ratio. The femur (as a percentage of the carcass) was shown to predict percentage carcass bone with 90% accuracy. All of the muscles studied were highly related to total carcass lean but the percentage of carcass as M. biceps femoris was the best single muscle indicator of carcass lean of the muscles studied. More variation in carcass lean could be accounted for by a multiple regression equation, involving all four muscles studied, than by any single muscle. M. biceps femoris-to-femur ratio was found to predict carcass muscle-to-bone ratio with a high degree of accuracy. The USDA yield grades were found to be reliable indicators of carcass composition. A two-variable equation involving adjusted fat thickness and biceps femoris accounted for 88·6% of the variation (RSD = 1/·64) in percentage of carcass as separable lean.

Relationships between chemical and physical body composition in two lines of Large White pigs at five feeding levels

The ARC Nutrient Requirement of Pigs (1981) has highlighted a shortage of information which would allow factorial estimates of chemical body composition to be related to physical carcase composition and commercial grading characteristics. The present study aimed to provide estimates of these relationships.Data related to weights of total carcass lean (Le), total carcass fat (TF), subcutaneous fat (SF), intermuscular fat (IF), total carcass bone (B), whole body crude protein (P), Lipid (Li), Ash (A) and Water (W) and backfat depths (P2, L2, shouTder(sh)) of 231 Newcastle selected (S) and control (C) boars.

EFFECTS OF DIETARY ENERGY INTAKE AND SEX ON CARCASS TISSUE AND OFFAL GROWTH IN SHEEP

Forty crossbred lambs (20 rams, 20 ewes) were penned in two groups (equal numbers of each sex) and fed a pelleted ration either ad libitum (H) or 70% of expected ad libitum intake (70% H). Ten lambs (5 rams, 5 ewes) from both groups (H and 70% H) were slaughtered after 40 days on feed while the remaining lambs were slaughtered after 61 days on feed. All lambs were measured for carcass leanness using an EMME machine immediately prior to slaughter. The offal components were weighed fresh and the alimentary tract was emptied of digesta. One side of each carcass was broken into four cuts (leg, loin, rib, shoulder) which were further separated into fat, muscle and bone. EMME numbers only marginally increased the amount of explained variation in the prediction of lean weight over that provided by liveweight alone. Growth coefficients between sexes and intake groups (H, 70% H) for the offal components relative to empty body weight were homogeneous, indicating that sex and dietary energy intake did not affect the relative growth of the offal components. Ram lambs had heavier heads and smaller intestines than ewe lambs, but contained less caul and mesenteric fat than ewe lambs at the same empty body weight. Lambs fed H had a greater weight of pelt, liver and caul fat, but had a lower warm carcass weight and less mesenteric fat than lambs fed 70% H at the same empty body weight. Growth coefficients between sexes and intake groups for the carcass tissues relative to physically separated tissue weights (muscle, bone, fat) were homogeneous, which indicated that sex and intake did not affect the relative growth of the carcass tissues. Ram lamb carcasses had a greater weight of muscle in the shoulder and less muscle in the leg than ewe lamb carcasses at the same carcass muscle weight. Dietary energy intake had small but statistically significant effects on carcass muscle distribution. Lambs fed 70% H produced carcasses with proportionally more muscle in the leg and less muscle in the loin and shoulder than lambs fed H at the same carcass muscle weight. Sex and dietary energy intake had minor effects on carcass bone and fat distribution. Key words: Lambs, carcass, offal, fat, EMME