Side Of Muscle Research Articles

Lateral preference in mastication: relation to pain.

Ten subjects performed deliberate right and left-sided chewing of gum, each exercise with a duration of 60 s, followed by maximum voluntary teeth clenching (MVC) until onset of pains in the masseter muscles (pain threshold). Contractile activities of the right and left masseter muscles were assessed by integrated and cumulative surface electromyography (EMG). When the right and left muscles functioned as chewing side muscles only, they generated practically identical levels of chewing force; the same applied when they functioned as non-chewing side muscles only. During identical functions, EMGs suggested identical motor unit recruitment and firing patterns in the two paired muscles; i.e., units producing relatively high tensions for chewing side activity, and other units producing relatively low tensions for non-chewing side activity. During isometric MVC activity, until onset of pains, the right and left muscles generated practically identical levels of bite force, but right and left motor unit activity patterns seemed to differ. Right and left motor units might have fired at different rates or begun to drop out at different times. In the latter case, rapidly before slowly fatigued units. There was a tendency for a low pain threshold with high chewing side activity in both masseter muscles. Motor units producing high levels of tension, but easily fatigued, might have caused early onset of muscle pains. No relationships could be established between preferred chewing side and side of initial muscle pains, nor between MVC activity and side of pain onset and preferred chewing side.

GROWTH PATTERNS OF MUSCLE, FAT AND BONE, AND CARCASS COMPOSITION OF DOUBLE MUSCLED AND NORMAL CATTLE

Eighteen Double Muscled (DM), 18 Beef Synthetic (SY) and 18 Hereford (HE) bulls were serially slaughtered from approximately 250 to 800 kg liveweight to determine the influence of maturity type and "double muscling" on tissue growth patterns and compositional differences which were examined by using the allometric equation Y = aXb after transformation to common logarithms (log10). As liveweight (LW) increased, the proportions of total side fat (TSF) and subcutaneous fat (SCF) increased, the proportions of total side muscle (TSM) and intermuscular fat (IMF) remained relatively constant and the proportion of total side bone (TSB) decreased. Relative to LW, DM had a similar growth rate for TSM and lower growth rates for TSF, SCF and IMF than HE and SY. All breed types had similar growth rates for TSB on LW. Relative to dissected side weight (DSW) and TSB, the DM bulls had a higher growth rate for TSM than did the HE and S Y bulls. Differences existed between DM and the more normal genotypes in carcass composition. DM was characterized by a high muscle:liveweight ratio, a high proportion of muscle in the carcass, high muscle:bone and muscle:fat ratios and a low proportion of fat compared to the more normal genotypes. Objective criteria to discriminate between HE and DM were SCF, muscle:bone and TSMTMF ratios, and between SY and DM were TSB and muscle:bone ratio. Key words: Beef bulls (young), growth patterns, carcass composition, double muscling, breed type

電気刺激が健常骨格筋に及ぼす影響について

低周波電気刺激が健常な骨格筋に与える影響を調べる目的でラットの右側坐骨神経に毎日30分間,2週間にわたり周波数5Hzの電気刺激を加えて筋肉を収縮させ反対側下腿筋を対照として比較し以下の結果を得た.刺激側の筋肉はより赤味を帯び,筋重量は前脛骨筋,長趾伸筋,長母趾伸筋でそれぞれ約5.8%,10.2%,37.1%増加した.筋線維1個当たりの毛細血管数は前脛骨筋浅層,中間層で対照側ではそれぞれ1.32,1.35であるが,刺激側の筋肉では,1.68,1.88個に増加した.また刺激側のすべての筋線維にコハク酸脱水素酵素活性の上昇が認められた.

Cardiac performance and myocardial blood flow in pigs with compensated right ventricular hypertrophy.

Compensated right ventricular hypertrophy (RVH), defined by a greater than 100% RV weight increase compared to 17 normal animals, was created in 17 young pigs by pulmonary arterial banding. RVH was associated with significant elevations (p less than 0.001) in RV peak dP/dt, RV stroke work, RV minute work and RV rate-pressure product compared to normal animals matched by body weight. RV peak dP/dt showed a positive correlation (p less than 0.001) with RV peak systolic pressure in normals; however, this relationship was lost in banded animals since progressively higher RV pressures were not associated with concomitant increases in RV peak dP/dt, thus, suggesting an intrinsic difference between right and left ventricles when working at systemic arterial pressures. Time to RV peak dP/dt became progressively longer (p less than 0.05) as RV weight increased in the RVH animals. When indices of cardiac work were normalized for RV weight, the RVH group could not be distinguished from normals suggesting that the performance per unit weight of RV muscle in RVH was unchanged. Total RV blood flow, measured by radioactive microspheres, closely followed (p less than 0.001) increases in RV mass in banded animals. Blood flow . g-1 muscle in RV and septal right side were unaltered in RVH; however, regional perfusion of the left ventricle (p less than 0.001) and septal right side were unaltered in RVH; however, regional perfusion of the left ventricle (p less than 0.001) and septal left side (p less than 0.02) increased significantly. There were regional variations in RV perfusion which were maintained in compensated RVH; stress (isoprenaline infusion) caused significant increases in blood flow to all regions of the heart in normal and RVH animals (p less than 0.001), but relative regional distribution was maintained. Our observations suggest a relationship between myocardial work and blood flow in RVH such that RV perfusion . g-1 is elevated to meet haemodynamic requirements once RV regional work . g-1 become greater than normal.

The splenius capitis muscle of the rat, architecture and histochemistry, afferent and efferent innervation as compared with that of the quadriceps muscle.

The splenius muscle of the rat was investigated with regard to its structure and innervation. The latter was compared with that of the quadriceps muscle. The results can be summarized as follows: The splenius muscles of both sides form a bipennate muscle plate connecting the occipital bone with the spinous process of the second thoracic vertebra. The lateral parts of both muscles are attached directly to this prominent bony process, whereas the medial parts end in a median raphe which forms a tendinous cranial extension of the second thoracic vertebra. This tendinous extension, showing no connection to the cervical vertebrae, serves also for the attachment of acromio-trapezius muscle fibers. The lateral part of the splenius muscle is divided into two parts by a tendinous intersection. The splenius muscle consists mainly of fast twitch fibers: 55% were characterized as IIB and 40% as IIA fibers by histochemical demonstration of myosin ATPase-activity. A high content of muscle spindles--57 spindles per gram of muscle tissue--was found. Comparing several aspects of the innervation of the splenius to that of the quadriceps muscle, the following results could be obtained: The ratio of motor end plate size to muscle fiber volume is significantly higher in the splenius than in the quadriceps muscle. As demonstrated by transganglionary HRP-transport, the main part of labeled splenius afferents to the spinal cord terminates in the central cervical nucleus. Quadriceps afferents, entering the lower thoracic and upper lumbar segments, mainly end in the area of Clarke's column. Several labeled fibers descend to the sixth lumbar and first sacral segments, where they terminate in the area of Stilling's nucleus. A group of primary afferents from both muscles--most probably III- and IV-afferents--projects to the dorsal laminae of the dorsal horn; terminals from the splenius are accumulated in the lateral parts of these laminae, whereas those of the quadriceps are more concentrated in the medial areas. Within the brain stem, most afferents from the splenius terminate in the external cuneate nucleus. Most of the quadriceps afferents course to the gracile nucleus. Terminals from both muscle nerves were found in the area of the spinal vestibular nucleus. In conclusion, the most conspicuous results were: 1) Besides the segmental projection to the dorsal horn there is an almost exclusive projection of splenius primary afferents to relay nuclei to the cerebellum. 2) The relatively high ratio: end plate size/muscle fiber volume, which is characteristic of finely adjusting muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Interlimb coordination of posture in patients with spastic paresis. Impaired function of spinal reflexes.

Activation of leg musculature on both sides following a unilateral displacement was studied during stance on separate see-saws, or on stable force-measuring platforms, in patients with spastic hemiparesis and paraparesis. During balancing the movements on the spastic side were damped and the degree of muscle activation reduced. Whereas in healthy subjects the tibialis anterior muscles of both sides were activated, following a unilateral displacement, with the same strength and latency (see-saws 55 ms, platforms 85 ms), in hemispastic patients the EMG responses were delayed (by about 20 to 30 ms) and of reduced strength on the spastic leg, irrespective of whether the unaffected or the spastic side was displaced. In addition, the compensatory movements on the spastic side were damped in both conditions, although the amplitude of displacement was the same bilaterally. Although there was no correlation between the delay and the reduction in EMG response, the latter was correlated with the severity of paresis. In patients with spastic paraparesis quite similar results were obtained with delayed and reduced EMG responses on both sides. It is concluded that in spasticity the impaired regulation of quick compensatory movements is due to a dysfunction of a spinal interneuronal system by which the early EMG responses are mediated. This could be explained by loss of supraspinal control. In addition to the impaired neural activation of leg muscles, changes in the mechanical properties of muscle can be assumed to contribute to the damped movements on the spastic side.

A caliper for determining carcass composition in live cattle and skin-on carcass

A Harpenden Skinfold Caliper used to predict body density in man was modified for use in cattle. It was used to measure thickness of the anal fold, caudal fold and rectal wall in 34 live steers or their skinon carcasses (hot dressed weight 139-339 kg). The value of these measurements in determining carcass fat and carcass muscle was compared with that of 10th and 12th rib fat thickness measurements made in the carcass. Hot carcass weight was the best predictor of side fat weight and side muscle weight. Side fat percentage and side muscle percentage were most accurately predicted by 12th rib and 10th rib fat thickness, followed by live then single-shackle anal fold fat thickness. The three caudal fold measurements and rectal wall thickness were poor predictors. Addition of hot carcass weight to all linear measurements markedly improved the prediction of side fat weight and side muscle weight, but nor side fat percentage and, only marginally, side muscle percentage. Single-shackle anal fold fat thickness, slightly less accurate than the live measurement, was the most useful skin-on measurement. The spring-operated caliper described can be used to determine carcass fatness and carcass lean in live steers with an accuracy closely approaching that of 12th rib fat thickness in the carcass.

Tissue growth patterns in the carcasses of water buffalo and Friesian crossbred cattle—part 1: Individual muscles and anatomical muscle groups

The left sides of the carcasses of twelve Egyptian buffalo, nine half Friesian (♂ Friesian x ♀ Egyptian Baladi) and nine three-quarter Friesian (♂ x ♀ half-Friesian) bulls, serially slaughtered between 161 and 560 kg for buffaloes and between 176 and 448 kg for cattle, were used to describe the growth and distribution of individual muscles and muscle groups. Genotype-group differences in the relative rate of growth were not significant in 85 of 89 muscles and in 8 of 9 muscle groups. The pooled within-group growth coefficients of individual muscles revealed different increasing growth gradients, i.e. disto-proximal in both limbs, mediolateral in the proximal pelvic limb, from elbow flexors to shoulder flexors in the proximal thoracic limb, caudo-cranial in the trunk and from hypaxial to epaxial muscles around the spinal column. The relative growth was lowest in the distal part of the limbs and highest in the anterior part of the carcass (SMG 7 and 8), with the loin and abdominal muscle groups growing at a rate similar to that of the total muscle. The neck and thorax muscle group grew at a higher rate in Friesian crosses than in buffaloes. Genotype-group differences in the weight of each muscle relative to total side muscle (TSM) were significant in 50 of 89 muscles. Of the 50 muscles (constituting around 59% of TSM), 24 (approximately 44% of TSM) were from the expensive muscle groups. As compared with the most different Friesian cross (base = 100) at equal TSM, buffaloes had higher weight of muscle in the hindlimb (107·5% proximally; 106·3% distally) and forelimb (120·0% proximally: 104·6% distally) and significantly less weight of the muscle groups forming the abdominal wall (79·8%) and connecting the forelimb to the thorax (89·1%) and to the neck (90·7%). The weight of the combined expensive groups was significantly greater in buffaloes than in cattle (maximum difference = 1·8 kg) with a tendency for buffaloes to have relatively less of the tender muscles surrounding the spinal column.

Electrical Capacitance of Dark‐cutting Beef

ABSTRACTElectrical capacitance was measured on the exposed adductor muscles of sides of beef. Measurements were made with a 3 mV 100kHz current between two parallel needle electrodes in the meat. Capacitance decreased after slaughter, and was correlated with the pH of the longissimus dorsi muscles in both normal (r = 0.94, P < 0.005) and in dark‐cutting carcasses (r = 0.89, P < 0.01). The normal decline of pH postmortem was curtailed in carcasses with dark‐cutting meat. However, when adjusted for differences in pH, ciircasses with dark‐cutting meat had a lower (P < 0.01) capacitance than carcasses with normal meat.

Influence of the supporting point on occlusal forces and masticatory muscle activities (author's transl)

Occlusal forces and masticatory muscle activities during clenching in the habitual occlusal position and right and left lateral positions were studied to clarify the optimum occlusal contacts in the various jaw positions. The occlusal forces and EMG activities were measured with the canine, premolar and molar regions on the occlusal splint as the supporting points. The highest occlusal force during maximum clenching was obtained at the molar supporting point, the second was at the premolar and the third at the canine, at every jaw position. The correlation between the occlusal forces and the EMG activities of the masseter and of the anterior and posterior temporal muscles on both sides was discussed at every supporting point. It was found that there was a linear relationship between them and the correlation coefficiency was remarkable in the case of the total EMG activities. The total EMG activities on the supporting side were higher than those on the non. supporting side. The ratio of the to total EMG activities on the supporting side to those on the non-supporting side decreased with the increase of the occlusal forces. The difference between the EMG activities of the masseter muscles of both sides became smaller than that of the anterior and posterior temporal muscles. It was concluded that the ratio of the EMG activity in each muscle to the total activities varied with the occlusal force and the location of the supporting points.

Isokinetic Torque Outputs of Professional and Elite Amateur Ice Hockey Players

Instrumentation advances have recently allowed the isokinetic evaluation of muscle function for purposes of injury diagnosis, rehabilitation, and training prescription. This type of evaluation has been particularly useful for athletes in preparing for performance or returning to training following injury. lsokinetic testing of specific muscle groups and at the approximate limb speeds required for performance of the sport has allowed more specific analysis of the functional strengths and weaknesses of athletes. Isokinetic testing allows comparison of agonist and antagonist muscle groups for balance across a joint, for right and left side muscle group comparison, and for joint angle at peak torque. Several athletic groups have already been characterized; alpine skiing, track and field (sprinting, jumping, and walking), and orienteering. The purpose of this study was to evaluate the function of important muscle groups for the performance of ice hockey. The data provided the basis for devising a training program for the athletes and also provided data for the characterization of professional (NHL) and elite amateur (Olympic) ice hockey players. Analysis also provided comparative information about the two groups.J Orthop Sports Phys Ther 1981;3(2):42-47.

Growth and development of water buffalo and Friesian cross-bred cattle, with special reference to body and carcass composition

SUMMARYA sample of twelve buffalo, nine O Friesian × ♀ Egyptian native Baladi (½ Friesian) and nine ♂ Friesian ×♀½ Friesian (¾ Friesian) bulls were individually penned and fed commercially cubed concentrates and roughages from weaning at 100 kg and slaughtered over the live-weight ranges 161–560 kg for buffaloes and 176–448 kg for cattle. Weights of gut fill (GFW), empty body (EBW), offals (TOW) and carcass were recorded. Right sides of all carcasses were jointed then dissected into muscle, fat, bone and ‘other tissues’. Analysis of covariance based on the allometric equationY=aXbwas applied to assess growth patterns (estimated from the slopes) and compositional differences (estimated from the intercepts).The effect of genotype-group was not statistically significant on EBW at the same fasted body weight and cold carcass weight at the same EBW. However, the buffalo empty body contained (P< 0·05) more offal than the ¾ Friesian empty body and heavier TOW and lighter hot carcass than ½ Friesian empty body of the same weight.No significant genotype-group differences were found in the slope of the regression of weight of total side muscle (TSM), total side fat (TSF), subcutaneous fat, intermuscular fat and total side bone (TSB) on dissected side weight (DSW) and ½ EBW. Comparison of adjusted means, however, showed buffaloes to have significantly more TSF and TSB but less TSM than the Friesian cross-breds. Most of the difference in TSF was due to more subcutaneous fat in the buffaloes than in the Friesian cross-breds. In all comparisons the two Friesian cross-bred groups did not significantly differ from one another.The results indicate that Egyptian buffaloes may be earlier maturing than Friesian cross-bred cattle and buffaloes of other countries. It was also concluded that in order to produce desirable carcass of fat:muscle ratio of 1:5, Egyptian buffalo bulls should be slaughtered to produce carcasses of slightly more than 230 kg whereas ½ Friesian and ¾ Friesian bulls can be taken to heavier weights. Methods for reporting carcass compositional data are discussed.

Effect of level of energy intake and influence of breed and sex on muscle growth and distribution in the bovine carcass.

Growth and distribution of muscle in the trunk, and thoracic and pelvic limbs were studied in 141 cattle ranging in slaughter weight from 121 to 706 kilograms. Holstein and Angus bulls, steers and heifers were fed at two levels of energy: ad libitum and 65 to 70% of ad libitum. The allometric equation Y = aXb was used to examine the effects of energy intake and of breed and sex on the rate of muscle growth of the three joints relative to the carcass side or to total muscle in the carcass side. Group comparisons of muscle distribution in the three joints were made after adjustment by regression to a total muscle weight of 53.1 kilograms. In both breeds, and irrespective of the level of energy intake, sex did not influence (P greater than .05) growth rate of muscle in the thoracic and pelvic limbs relative to the carcass side or to total muscle. However, sex was found to affect growth rate of muscle in the trunk relative to the carcass side. Generally, neither level of energy intake nor breed altered (P greater than .05) growth rate of muscle in the three joints relative to the carcass side or total muscle. The distribution of muscle in the three joints adjusted to a total muscle weight of 53.1 kg was generally not influenced (P greater than .05) by sex or altered (P greater than .05) by the level of energy intake. Breed influenced (P less than .05) the distribution of muscle in the trunk and pelvic limb; however, the commercial importance of this difference is questionable.

THE GROWTH AND DISTRIBUTION OF MUSCLE IN BULLS AND HEIFERS OF TWO BREEDS

A trial is reported comparing muscle growth and distribution in 12 bulls and 12 heifers of each of two breed-types: Hereford (HE) and Dairy Synthetic (DY). Serial slaughter was carried out from weaning (163 ± 15.1 days) to approximately 15 mo of age. After slaughter, the left side of each carcass was broken into quarters and then eight wholesale cuts, which were separated into fat, muscle and bone. The growth pattern of muscle in each cut relative to total side muscle was estimated from the growth coefficient, b, in the allometric equation (Y = aXb). Growth coefficients were homogeneous among breeds and sexes, indicating that neither breed nor sex influenced relative muscle growth. Some significant (P < 0.05), though minor, sex and breed differences were found when muscle weight distribution was adjusted to constant side muscle weight. Notably DY heifers had significantly (P < 0.05) more muscle in the high-priced cuts (sum of round, sirloin, loin and rib) than either HE heifers or bulls of either breed-type. When muscle weight was adjusted to constant side weight, bulls were found to have a greater weight of muscle in the high-priced cuts than heifers, and DY animals to have more than HE animals.

EFFECTS OF BREED AND SEX ON THE PATTERNS OF FAT DEPOSITION AND DISTRIBUTION IN SWINE

The growth and distribution of fat from 163 pig carcasses were compared among five breeds (Duroc × Yorkshire (D × Y), Hampshire × Yorkshire (H × Y), Yorkshire (Y × Y), Yorkshire × Lacombe-Yorkshire (Y × L-Y) and Lacombe × Yorkshire (L × Y)) and two sex-types (barrows and gilts) over a wide range in carcass weight. The growth pattern of fat and the fat depots were estimated from the allometric equation (Y = aXb) using side muscle weight and side fat weight separately as independent variables. Growth coefficients (b) for intermuscular and subcutaneous fat depots were similar for the hindquarter but the intermuscular depot coefficient was slightly higher for the forequarter. The coefficient for body cavity fat was highest in all comparisons. No significant differences were detected for coefficients among breeds and between sexes using both total muscle and total side fat as independent variables. Significant breed and sex-type differences were found in the fat depots at a constant weight of side muscle. This would indicate that breed differences in fatness seemed to be more influenced by the initiation of fattening at different muscle weights than by any inherent differences in rate of fattening. Significant breed differences were also found in the fat depots at a constant fat weight, indicating that breed may influence fat distribution. Sex-type had no effect on fat distribution when the evaluation was made at constant fatness.

Development of body components in Kenana cattle. 2. Relative weight changes of major carcass tissues

SummaryThirty-two weaned Kenana bull calves were adequately fed to maximize growth and serially slaughtered at predetermined live weights of 100, 200, 300 and 400 kg. Eight animals were slaughtered at each slaughter point and the left side of each carcass dissected into individual muscles, bone, fat, tendons and fascia. Individual muscles were grouped into nine muscle groups and the distribution of intermuscular fat was studied in four anatomical regions. Huxley's (1932) allometric equation was used to describe the development of carcass tissues.Relative to overall carcass side growth, fat was the fastest developing tissue, followed by muscle and bone tissues in descending order. The muscles of neck + thorax and abdominal muscles exhibited the fastest rate of growth relative to overall total side muscle growth, and the distal muscles of both limbs exhibited the slowest rate of relative growth. Relative to the rate of side fat deposition throughout the experiment, subcutaneous fat was deposited at a faster rate than intermuscular or kidney + channel fat. Intermuscular fat was deposited at different rates in the anatomical regions of the carcass.The development of muscle groups was further examined in three arbitrary phases of the test period and revealed significant differences between phases in the rate at which each muscle group developed. Similar changes in the intensity of the rate at which fat was deposited in the subcutaneous region and between the muscles of the carcass or sites were evident.Kenana cattle compare favourably with foreign dairy and beef breeds of cattle in muscle:bone ratio. Further studies are needed to evaluate the efficiency of meat production from Kenana cattle under different systems of management.As reported in Part 1 (Gaili & Nour, 1980) a study was conducted to investigate the development of body components in Kenana cattle and to evaluate the potential of the breed for meat production. This paper is an account of the data which were obtained on the development of carcass tissues.

Asymmetrical Muscle Activity During Feeding in the Gar, Lepisosteus Oculatus

ABSTRACT Prey capture in the spotted gar, Lepisosteus oculatus, was studied by high-speed cinematography synchronized with electromyographic recordings of cranial muscle activity. Muscle activity patterns were recorded during each of the three major phases of feeding: the initial strike at the prey, manipulation of the prey following capture, and swallowing. With one exception, the obliquus superioris, all muscles at the strike are active in a bilaterally symmetrical pattern. During the manipulation phase two distinct muscle activity patterns occur: one is characterized by symmetrical activity in the epaxial muscles and obliquus inferioris, the other by complete asymmetry between the right and left sternohyoideus, obliquus superioris, and epaxial muscles. Low-amplitude manipulatory movements are characterized by activity in one side of the sternohyoideus only, all other muscles being generally inactive. The adductor mandibulae and obliquus inferioris are always active symmetrically. Asymmetrical activity in the sternohyoideus, epaxial muscles, and obliquus superioris correlates with lateral head movements during feeding and acts to rotate prey into the preferred orientation for swallowing. The pattern of asymmetrical activity between right and left side muscles is discussed in relation to previous studies of feeding which utilized only unilateral muscle recordings.

An evaluation of some methods of predicting muscle weight of cattle

The accuracy of some published equations to predict side muscle weight of cattle was assessed by fitting data from cattle of known carcase composition to them. A method of comparing the accuracy of different prediction equations is also described. The results indicated that there was considerable variation between the prediction equations in the accuracy with which they predicted side muscle weight in the test data. This suggests that such prediction equations should be applied to independent sets of data with extreme caution.

A comparison of tissue weight distribution in Landrace, Hampshire and Duroc Jersey pigs

SUMMARYThe carcasses of 20 Landrace, 20 Hampshire and 20 Duroc Jersey barrows were dissected in order to study the influence of the breed on tissue weight distribution.After weaning, at 56 days of age, the animals were allocated to individual pens and fed a standard diet containing 18% crude protein and 13 MJ ME/kg, until they reached their designated slaughter weight.The Landrace and Hampshire pigs were slaughtered between 60 and 115 kg and the Duroc Jersey ones between 40 and 115 kg live weight. The right half carcasses were completely dissected using strictly anatomical criteria. Individual muscles were classified into eight anatomical groups (Carden & Goenaga, 1977).The results were examined by covariance analyses utilizing the allometric equation. Carcass tissue composition was studied using the weight of the dissected side as covariate. When muscle: bone ratio was examined, the weight of total side muscle was used as the independent variable. The growth of different parts of a tissue relative to the corresponding whole tissue was studied.Concerning carcass composition, there were significant breed differences in muscle and fat contents and in the muscle:bone ratio.Breed differences were found in muscle distribution. The 6 values of muscle groups 1 (proximal hind limb), 2 (distal hind limb), 6 (distal forelimb) and 7 (muscles connecting forelimb to thorax) were statistically different as were the adjusted means of groups 3 (spinal column), 5 (proximal forelimb) and 8 (muscles connecting forelimb to neck and intrinsic muscles of neck and thorax).Significant differences were also found in bone weight distribution. Slope values of the tarsals, os coxae, scapula and sternum were statistically different. Adjusted means of tibia-fibula, sacrum, spinal column, radius-ulna, carpals and ribs were also significantly different.Finally, there were breed effects in the distribution of fat, the relative weight of subcutaneous and of intermuscular fat being statistically different.

The use of non-carcass parts in the prediction of beef carcass composition on the slaughter floor

Ninety-five steers were used to develop a method of estimating the weights or percentages of the four carcass tissues—muscle, bone, fat and connective tissue—while the carcasses were still on the slaughter floor. From an investigation of a number of non-carcass parts it was found that three measurements could be used to estimate all four carcass components. The measurements were (a) short-cut tongue weight; (b) foreshanks weight; (c) hot side weight. Simple and multiple regression equations were developed to estimate the weights of muscle, bone and connective tissue in the chilled side, and the accuracy of the estimates was compared with that of recorded prediction methods. The most useful equations employed short-cut tongue weight and hot side weight to estimate total side muscle weight, and foreshanks weight to estimate both total side bone weight and total side connective tissue weight. Fat weight was estimated from hot side weight and the estimates of the weights of the other three carcass components. This technique was more accurate than the Australian Beef Carcase Appraisal System and Butterfield's equation, both of which use fat thickness measurement at the 10th rib. When fat thickness measurement was included in regression equations, the estimates of muscle weight and fat weight were slightly improved. Advantages of using the 'non-carcass parts' technique are as follows. All four major carcass components are predicted; the carcass components can be recorded as absolute weights or percentages of chilled side weight; chilled side components are predicted whilst the hot side is still on the slaughter floor; no commercial loss occurs in carcass, offals or by-products; all measurements used in prediction are weights; and fat thickness measurements may be included in the prediction. The additional information enables producers to make a more critical assessment of the nutritive performance and genetic progress of their herds.