Heifer Carcasses Research Articles

Electromagnetic scanning of beef quarters to predict carcass and primal lean content.

To study the use of electromagnetic scanning in prediction of lean content in beef carcasses and cuts, 100 beef cattle (60 steers and 40 heifers), representing a broad range in external fat thickness (.1 to 2.9 cm) and live weight (414 to 742 kg), were selected. Chilled right sides were divided into streamlined (foreshank, brisket, and ventral plate removed) forequarters (FQ) and full hindquarters (HQ) and scanned. Primal rounds, loins, ribs, and chucks were fabricated from the right side, scanned, and physically separated into lean, fat, and bone. Prediction equations for dissected lean content and percentage of lean included the peak of the electromagnetic scan response curve (obtained from scanning the HQ or FQ), length, temperature and weight of the scanned cut, and fat thickness at the 12th rib. Using the coefficient of determination, root mean square error, and Mallows' Cp statistic, the best model for each dependent variable (weight and percentage of lean) that included up to five independent variables was selected. Prediction equations for the HQ or FQ of steers accounted for 84 to 93% of the variation in lean weight of beef sides and quarters and 71 to 93% of primals. Sixty-one to 75% of the variation in percentage of lean in sides and quarters and 48 to 65% of primals was also explained. Similar results were obtained for heifer carcasses. Predicting percentage of lean in any scanned cut, rather than weight of lean, accounted for less of the variation. Weight and fat thickness contributed significantly when predicting percentage of lean.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Proteinated Minerals and Yeast Culture on Growth and Carcass Characteristics of Fattening Heifers

Feed additives which enhance the growth rate of beef cattle during the fattening period would be of benefit to the industry. The effects of dietary supplementation with “Bio-Boost Plus”, a product containing mineral proteinates (Cu, Zn, Mn) and yeast culture on heifer growth rate and carcass characteristics were examined. The response to the inclusion of yeast culture in the diet of fattening cattle was a 7.5% increase when averaged over sixteen different studies (Wallace and Newbold, 1993). It was postulated that the response to yeast culture would be increased with the inclusion of proteinated minerals Cu, Zn and Mn to the daily diet.Seventy two 16 month old continental cross heifers with an initial liveweight of 393 kg were assigned on a liveweight basis to one of two treatments: a) control - diet consisting of grass silage ad libitum plus 3 kg of concentrates per head per day; b) Bio-Boost Plus - control diet supplemented with 15 g of Bio-Boost Plus per head per day. Heifers were group penned according to treatment (8 pens of 9 animals) for the 131 day experimental period. The daily concentrate (rolled barley 900, soyabean meal 80 and minerals and vitamins 20 g/kg) allowance was offered in one feed each morning and the Bio-Boost Plus was added as a top dressing to the concentrate.

Beef carcass composition of slaughter cattle differing in frame size, muscle score, and external fatness.

Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.

Evaluation of mating systems involving five breeds for integrated beef production systems: II. Feedlot segment.

Computer models were used to simulate the feedlot segment of an integrated beef production system. Five breeds, Angus (A), Charolais (C), Hereford (H), Limousin (L), and Simmental (S), in three mating systems, pure-breeding and two- and three-breed rotational crossbreeding, were evaluated for feedlot and carcass performance. Breed data were taken from the literature. Feeder calves (steers and non-replacement heifers) entered the feedlot at 205 d of age. After a 35-d adjustment period, calves were custom-fed to four slaughter end points: 440 d, 457 d, 288-kg carcass weight, or low Choice. Cattle were fed to requirements (megacalories of ME). Input costs included feed and nonfeed expenses (purchase prices, transportation, yardage, and medicinal fees). Carcass values were $2.65 and $2.54/kg of carcass weight for steer and heifers, respectively, between 272 to 318 kg. Over- or underweight carcasses were discounted $.60/kg. At the 440-d end point, Select grade steer and heifer carcasses were discounted an additional $.22 and $17/kg, respectively. Biological efficiency was measured as megacalories of ME/kg of gain, and economic efficiencies were measured as input costs per kilogram of carcass weight, input costs per kilogram of lean weight, and input costs per carcass value. Continental breed combinations (C and S) were most efficient at age- and weight-constant end points for megacalories of ME per kilogram of gain and for input costs per carcass value and most efficient at all end points for input costs per kilogram of carcass weight and input costs per kilogram of lean weight. British breed combinations (A) were most efficient at a fat-constant end point for megacalories of ME per kilogram of gain and input costs per carcass value. Therefore, choosing breed combinations for feedlots depends on slaughter end point and measures of efficiency.

A survey of marbling fat in Canadian beef carcasses

Marbling score was assessed in 20 437 Canadian beef carcasses on a 10-point scale (1 = very abundant, 10 = devoid) in six provinces during the period August to November 1989. Heifer carcasses had a lower marbling score (more marbling fat) than steer carcasses, and both had lower marbling scores (more marbling fat) than bull carcasses. Marbling increased as Canada grade changed from B1 to A1 and from A1 through to A4, indicating that marbling fat increased with carcass fatness. The regression of marbling score on carcass weight and carcass 12th rib fat thickness, although significant, showed that these traits only accounted for 0.5 and 6%, respectively, of the overall variation in marbling score. The overall distribution of marbling scores showed that 20.6% of carcasses had small or more marbling, 57.9% had slight marbling, 20.4% had traces of marbling and 1.1% were devoid of marbling. Key words: Beef, carcass, marbling, survey

Maternal breed of sire effects on postweaning performance of heifer and steer progeny: postweaning growth and carcass characteristics

Heifer and steer progeny of 2-yr-old first-cross (F1) heifers and 3- to 6-yr-old F1 cows, from Hereford dams and five sire breeds, were evaluated for postweaning feedlot growth and carcass composition. Breeds of sire of dam were Angus (A), Red Poll (RP), Tarentaise (T), Simmental (Sm), and Pinzgauer (P). Calves from 2-yr-old heifers were sired by Shorthorn, and calves from 3- to 6-yr-old dams were sired by Charolais. Breed of sire of dam was significant (P less than .05 to P less than .01) for total gain and final weight for female progeny from 2-yr-old dams. At all weights, Sm, P, and T ranked above A and RP. Progeny of A, P, Sm, and T F1 2-yr-old dams were not significantly different but were higher (P less than .05) than RP heifers in total feedlot gain. Breed of sire of dam was significant (P less than .05) for carcass weight and longissimus muscle area; T ranked highest and RP lowest. Breed was not significant for any growth traits of steer progeny of 2-yr-old dams. Breed was significant for marbling score; A ranked highest and exceeded (P less than .01) both RP and Sm steers. Breed was significant (P less than .05) for most growth traits in the heifer progeny of the 3- to 6-yr-old dams bred to Charolais sires. Heifer calves of the Sm group were heavier (P less than .05) than all other groups for most weights and total gain. For total gain, P and T were intermediate and A and RP lowest. For heifer carcass traits from 3- to 6-yr-old dams, breed was significant (P less than .05 to P less than .01) for carcass weight, longissimus muscle area, percentage of cutability, and estimated kidney, heart, and pelvic fat. Heifers from Sm-sired dams were heavier (P less than .05) than those from all other groups but ranked second to heifers from P for percentage of cutability. Marbling scores of RP heifer carcasses ranked highest of all groups. Breed was not significant (P greater than .05) for any of the weights or gains in steer progeny of 3- to 6-yr-old dams; however, the Sm and P groups ranked above A and RP for all feedlot test weights.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of Beef Tenderness: Development and Verification

ABSTRACTEquations were developed to predict beef longissimus dorsi (LD) tenderness after postmortem refrigerated aging. Warner‐Bratzler shear force (WBSF) and myofibril fragmentation indices (MFI) were determined at 1, 3, 7 and 14 days postmortem on LD of Angus‐Hereford (AH, n = 8) and 5/8 Brahman crossbred (n = 8) heifer carcasses. Correlation coefficients between WBSF and MFI were −0.91, −0.74, −0.63, and −0.40 at 1, 3, 7 and 14 days postmortem, respectively. None of the traits measured correlated significantly with 14‐day WBSF (P > 0.05). A three‐variable prediction equation that included 24‐hr calcium‐dependent protease (CDP) inhibitor activity, 0‐hr CDP‐I activity and 24‐hr cystatin activity accounted for 63% of the variation in 14‐day WBSF.

Relationship between marbling group and major muscle contribution to beef carcass mass.

Left sides from 18 beef carcasses (9 steers and 9 heifers) were divided equally among three marbling groups (low = traces or slight; intermediate = small or modest; high = slightly abundant) and evaluated to determine the relationship between longissimus composition and the percentage each major muscle contributes to the weight of the beef carcass. The adductor (A), biceps femoris (BF), deep pectoral (DP), gluteal group (GL), infraspinatus (I), longissimus (L), psoas major (PM), rectus abdominis (RA), rectus femoris (RF), semimembranosus (SM), semitendinosus (ST), serratus ventralis (SV), spinalis (SP), supraspinatus (SU) and triceps brachii (TB) were removed, trimmed of external fat and weighed. Muscle weights were expressed as a percentage of hot carcass weight: A = .76%; BF = 3.30%; DP = 1.89%; GL = 1.81%; I = 1.10%; L = 3.35%; PM = .95%; RA = 1.12%; RF = .94%; SM = 2.35%; ST = 1.14%; SV = 2.26%; SP = .82%; SU = .69% and TB = 1.83%. The deep pectoral and triceps brachii were heavier (P less than .05) in steer carcasses than in heifer carcasses. No other significant sex effects were noted. Percentage of muscle tended to decrease with increasing marbling level; however, the linear regression of relative muscle weight on marbling level was significant for the BF, DP, PM, SM, SU and TB. Using marbling score or yield grade factors to predict the percentage of individual muscles in the carcass resulted in R/ values greater than .4 in 7 of the 15 muscles evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

The usefulness of muscle color and pH for segregating beef carcasses into tenderness groups

A total of 3435 beef carcasses from animals 11 to 14 months of age (472 bulls, 978 heifers, 1985 steers) were evaluated over a ten year period to determine the usefulness of measurements of muscle color and pH for segregating carcasses into tenderness groups. All carcasses were aged for 6 days at 2°C. Color and pH measurements were obtained on the longissimus† muscle. A loin steak from the eleventh-twelfth thoracic vertebrae interface was microwaved to approximately 70°C to determine shear force values. Steers had the lowest ultimate pH and shear force values and bulls had the highest (P=0·0001). Steers also had lighter colored lean (P=0·0001) than bulls and heifers (i.e. higher mean colorimeter readings). Arbitrary segregation of carcasses into tenderness groups based on shear force values (⩽6·0 tender; >6·0 tough) resulted in the tender group having higher colorimeter readings (17·40 versus 16·76, P=0·0001) and ultimate pH values (5·70 versus 5·69, P=0·02) and lower shear force values (4·89 versus 7·65, P<0·0001). Year and breed effects were observed in all three traits (P=0·0001). However, time trends were not detected and the range in shear force values among breeds was relatively narrow (6·02–6·74). Subjective color scores, colorimeter readings, and ultimate pH values accounted for 48% or less of the variation in shear force values in all sex, year, and breed groups indicating that generally none of these traits were highly related to tenderness in a linear fashion. Arbitrary segregation of carcasses into tenderness groups based upon shear force value resulted in consistently higher shear force values for the toughh group (SV>6·0) and lower values for the tender group (SV⩽6·0) (P<0·05) than the overall mean shear force value in all sex groups. Plotting of colorimeter readings and ultimate pH values against shear force values resulted in peaks within the range of colorimeter readings 8·5–16·5 and pH values 5·8–6·19. Segregation of carcasses with colorimeter readings within the range 8·5–16·5 was effective in segregating the tough ess steer and heifer carcasses and the tender bull carcasses, while segregation based upon pH values between 5·8 and 6·19 was effective in segregating the tough carcasses in all sex groups. Segregation based on both color and pH appeared to offer little advantage over the use of pH alone. Segregation of beef carcasses with ultimate longissimus pH values between 5·8 and 6·19 appears to be an easy, nondestructive, practical means to effectively remove the majority of tough carcasses (shear value >6·0) in all three sex groups, regardless of breed.

FACTORS AFFECTING BEEF COLOR AT TIME OF GRADING

The color of the longissimus dorsi (LD) muscles from 7695 beef carcasses was evaluated following carcass grading at a commercial abattoir in the Central Alberta Region. Darker-than-normal beef was found in 3.7% of steer and heifer carcasses. However, the incidence of true dark-cutting beef (i.e., dark in color and with a pH greater than 6.0) was estimated to be only 0.5%. The length of time between stunning and the measurement of color had a major impact on color. The incidence of dark-colored beef was three times higher at 15–18 h than at 23–26 h poststunning, apparently because of incomplete development of muscle color at the earlier times. Carcass fat cover, weight and conformation affected muscle color, with smaller and leaner carcasses yielding higher frequency of dark-colored beef. Other factors influenced muscle color, including: (1) gender, (2) nutritional regime, (3) transit distance, (4) lairage time at the abattoir and (5) weather conditions. All of these could be explained by their effect on the time of color measurement or on carcass size and fatness. These findings indicate that if meat color is evaluated during the first 24 h postslaughter, it may be affected by many factors not related to preslaughter stress. During this time period accurate assessment of ultimate muscle color of the dark-cutting condition of conventionally-handled carcasses is not possible. Key words: Beef, color, dark cutting, stress

EFFECT OF WEIGHT AND FAT COVER ON CHILLING RATE OF CONVENTIONALLY PROCESSED STEER AND HEIFER CARCASSES

Chill rates over the initial 24 h after slaughter were determined on 382 carcasses (209 steers, 173 heifers) at two anatomical locations (rib and hip) in animals slaughtered at 13.5 and 15.0 mo of age. The objectives of the study were to determine if chill rates differed between steer and heifer carcasses and the influence of hot carcass weight and fat cover on the prediction of chill rate. Steer carcasses chilled at a slower rate than heifer carcasses at the rib location but did not differ in chill rate at the hip location. Both hot carcass weight and fat cover significantly contributed to the determination of chill rate at the rib but only hot carcass weight was important in the determination of chill rate at the hip. At the rib location hot carcass weight had a greater influence than fat cover in accounting for variation in chill rate. The majority of the variation in chill rate at either location was due to factors other than hot carcass weight and fat cover. Key words: Beef carcass, chill rate, carcass weight, fat cover

The effect of a short finishing period for weaned once-bred heifers prior to slaughter on carcass height and composition

Previous work carried out at Aberdeen to investigate the effect of varying the length of the suckling period post calving on heifer and calf performance has shown little difference in the carcasses of heifers slaughtered twelve weeks post calving compared to heifers slaughtered six weeks post calving (Lowman and Broadbent, 1988). These results further emphasise the nutritional demand for lactation and suggest that major improvements in carcass weight of calved heifers can only be obtained if they are weaned early or allowed an appropriate finishing period after weaning. An experiment was therefore set up to examine the effect of a short finishing period for weaned once-bred heifers prior to slaughter on carcass weight, composition and eating quality and to relate these findings to a group of non-pregnant heifers.

Use of Mononuclear Leukocyte Insulin Receptor Characteristics as Predictors of Carcass Composition in Heifers and Steers

Total insulin specific binding (IB) and the number and affinity of insulin receptors on mononuclear leukocytes (MNL) were used to predict carcass composition of heifers and steers. Dependent variables were kidney fat, body cavity fat, s.c. fat, intermuscular fat, lean and bone. Independent variables were parameters that could be measured on the live animal, including insulin receptor characteristics, age, shrunk weight, breed and carcass s.c. rib fat thickness (SUB). All carcass fat characteristics and IB were greater for heifers than for steers, but the ability to predict either heifer or steer carcass fat characteristics was not improved by inclusion of IB in prediction equations. However, the number of low-affinity insulin receptors on MNL contributed significantly to the prediction of all heifer carcass characteristics except bone. Carcass s.c. rib fat thickness also entered the prediction equations for all heifer carcass characteristics except kidney fat. In the prediction of heifer kidney fat, the only significant independent variable was the number of low-affinity insulin receptors on MNL (R2 = .38). Carcass characteristics of steers were better predicted by SUB than were heifer carcass characteristics, and insulin receptor characteristics, when added to steer equations that contained SUB, improved R2 by .10 or less. Our results suggest that insulin receptor characteristics will be most useful in the prediction of carcass characteristics of heifers where there is a poor relationship between quantity of s.c. fat and other carcass fat depots.

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.

THE EFFECTS OF CARCASS GRADE AND SEX ON THE LEAN CONTENT OF BEEF CARCASSES

Heifer (n = 82) and steer (n = 89) carcasses were compared for lean content at the same grade (Canada A1 or A2), or at the same depth of average rib fat thickness within a grade (8.5 or 12.1 mm). Lean content for A1 grade carcasses was found to average 63.3% with a range from 55.6 to 69.2%. The corresponding figures for A2 grade carcasses were 60.0% lean and a range from 53.7 to 66.2%. A1 grade steer carcasses were found to contain 1.7% more lean than A1 grade heifer carcasses, but this difference was reduced to 1.2% when the comparison was made at an equal depth of subcutaneous fat thickness. There were no sex differences in lean content for A2 grade carcasses. The results are discussed with reference to lean content variation in existing carcass grades and pricing policies for heifer and steer carcasses of the same carcass grade. Key words: Beef, carcasses, steer, heifer, composition, grade

Use of the Hennessy Grading Probe (GP) for predicting the meat, fat and bone yields of beef carcasses

Left sides of 36 bulls, 22 cows, 57 steers and 38 heifer carcasses were weighed hot (HCWL) and were probed with the Hennessy Grading Probe (HGP) at five sites to give four subcutaneous fat depths, two M. longissimus dorsi depths and one total tissue depth measurement. A fat depth (GR) over the 10th rib was also measured by ruler probe. The left sides were later separated by knife into saleable eat (90% visual lean), fat trim and bone. Probe readings of subcutaneous fat thickness at the fatter rump sites (BF, 5–7 cm lateral to the perianal region over the M. biceps femoris; SC8, 8 cm lateral to the prominence of the sacral crest) were smaller than ruler measurements at the same sites. Probe eye muscle depth measurements were smaller than measurements taken at the same site by ruler. The BF measurement taken by probe, combined with HCWL, gave the best prediction of percentage fat trim (RSD = 2·0% for steers and 2·2% for heifers) and edible meat yield (RSD = 2·0% for steers and 2·6% for heifers) in the left sides of all the measurements studied, either singly or in combination. A major problem was to find a measurement site where subcutaneous fat was not removed from some carcasses during hide removal.

Why Spay Heifers?

The price spread between steers and heifers is the most important reason buyers purchase market heifers. To illustrate this price difference consider the following information summarized from a marketing study reported in 1979 comparing steer and heifer prices:11. The average heifer calf was worth about $58.00 less than the average steer calf due to weight and price. 2. Feeder heifers sold for about 15% less than feeder steers of similar quality.3. Fat heifers sold for approximately 4% less than fat steers of comparative quality.4. Heifer carcasses were valued at approximately 5% less than steer carcasses. &#x0D; This price differential is a strong indication that most stocker and feeder cattle buyers have a strong preference for steers. A further look at market prices also shows that slaughter steers consistently sell for more per hundred weight than comparative fat heifers. Why?

Percentage Ether Extractable Fat and Moisture Content of Beef Longissimus Muscle as Related to USDA Marbling Score

ABSTRACTPercentage fat and moisture values for beef longissimus steaks (trimmed completely of all subcutaneous fat, epimysium, and peripheral muscles) from 518 steer and heifer carcasses of A and B maturity over a wide range in marbling were as follows: Moderately Abundant = 10.42 and 68.14, Slightly Abundant = 8.56 and 69.56, Moderate = 7.34 and 70.35, Modest = 5.97 and 71.35, Small = 4.99 and 72.36, Slight = 3.43 and 73.61, Traces = 2.48 and 74.29, and Practically Devoid = 1.77 and 75.37.

The composition, fat distribution and yield of carcass beef from steers and heifers when entire, spayed, pregnant or fitted with an intravaginal device

An experiment at the Pastoral Research Institute, Hamilton, compared the carcass composition and yield of one group of 14 Hereford steers, and four groups of 14 heifers, either spayed, fitted with an intravaginal device, pregnant or entire. The animals were slaughtered at 18 or 22 months when average fat depths and carcass weights were 5.8 mm and 188.0 kg, or 7.5 mm and 219 kg, respectively. When compared at a constant carcass weight, the steers generally had heavier boneless primary cuts, with less fat than the heifers (P&lt;0. 05). Steers also had less channel and kidney fat, subcutaneous fat, intra-muscular and inter-muscular fat and consequently less total fat than heifers (P&lt;.05) . Differences between heifer groups were generally small and non-significant. When compared at the same age, differences between heifers and steers in carcass fatness were generally not significant (P&gt;0. 05) but trends similar to those described above were apparent. Estimated yield of carcass beef (muscle plus saleable fat) was affected by sex, fat depth and level of fat specified in the carcass beef. When lean carcass beef (1 5% fat) was specified, steers yielded about 3.8% more than heifers at the same weight and fat depth, but when fatter carcass beef (20% fat) was specified, this difference was reduced to about 3.2%. Removal of channel and kidney fat from the carcass brought the yield of steer and heifer carcasses to within about 3.0% of each other.

Lipid Characterization of Longissimus and Biceps Femoris Muscles from Beef Animals Exsanguinated at Various Times after Stunning

ABSTRACTLipid characteristics of bovine longissimus and biceps femoris muscle from 30 heifer carcasses which were exsanguinated 0 (control), 3 or 6 min after stunning were studied. Blood loss was greater when control animals were compared to animals stunned 3 or 6 min prior to exsanguination. However, total lipid, lipid phosphorus, cholesterol values and TBA numbers were similar among treatments. As time between stunning and exsanguination increased, monounsaturated and polyunsaturated fatty acids tended to increase. Delaying time between stunning and exsanguination had little influence on lipid characteristics of muscle even though large differences between lipid characteristics of muscle and blood exist.