Biomedical subjects

J D Crouse

Publications and source records attributed to J D Crouse.

At least 19 recordsLinked to original sources

PubMed2006

Manure composition of swine as affected by dietary protein and cellulose concentrations.

An experiment was conducted to investigate the effects of reducing dietary CP and increasing dietary cellulose concentrations on manure DM, C, N, S, VFA, indole, and phenol concentrations. Twenty-two pigs (105 kg initial BW) were fed diets containing either 14.5 or 12.0% CP, in combination with either 2.5 or 8.7% cellulose. Pigs were fed twice daily over the 56-d study, with feed intake averaging 2.74 kg/d. Feces and urine were collected after each feeding and added to the manure storage containers. Manure storage containers were designed to provide a similar unit area per animal as found in industry (7,393 cm2). Before sampling on d 56, the manure was gently stirred to obtain a representative sample for subsequent analyses. An interaction of dietary CP and cellulose was observed for manure acetic acid concentration, in that decreasing CP lowered acetic acid in pigs fed standard levels of cellulose but increased acetic acid in pigs fed greater levels of cellulose (P = 0.03). No other interactions were noted. Decreasing dietary CP reduced manure pH (P = 0.01), NH4 (P = 0.01), isovaleric acid (P = 0.06), phenol (P = 0.05), and 4-ethyl phenol (P = 0.02) concentrations. Increasing dietary cellulose decreased pH (P = 0.01) and NH4 (P = 0.07) concentration but increased manure C (P = 0.03), propionic acid (P = 0.01), butyric acid (P = 0.03), and cresol (P = 0.09) concentrations in the manure. Increasing dietary cellulose also increased manure DM (P = 0.11), N (P = 0.11), and C (P = 0.02) contents as a percentage of nutrient intake. Neither cellulose nor CP level of the diet affected manure S composition or output as a percentage of S intake. Headspace N2O concentration was increased by decreasing dietary CP (P = 0.03) or by increasing dietary cellulose (P = 0.05). Neither dietary CP nor cellulose affected headspace concentration of CH4. This study demonstrates that diets differing in CP and cellulose content can significantly impact manure composition and concentrations of VFA, phenol, and indole, and headspace concentrations of N(2)O, which may thereby affect the environmental impact of livestock production on soil, air, and water.

Animal Feed↗

PubMed2004

Genetic relationships between sex-specific traits in beef cattle: mature weight, weight adjusted for body condition score, height and body condition score of cows, and carcass traits of their steer relatives.

Data from the first four cycles of the Germplasm Evaluation Program at the U.S. Meat Animal Research Center (USMARC) were used to investigate genetic relationships between mature weight (MW, n = 37,710), mature weight adjusted for body condition score (AMW, n = 37,676), mature height (HT, n = 37,123), and BCS (n = 37,676) from 4- to 8-yr old cows (n = 1,800) and carcass traits (n = 4,027) measured on their crossbred paternal half-sib steers. Covariance components among traits were estimated using REML. Carcass traits were adjusted for age at slaughter. Estimates of heritability for hot carcass weight (HCWT); percentage of retail product; percentage of fat; percentage of bone; longissimus muscle area; fat thickness adjusted visually; estimated kidney, pelvic, and heart fat percentage; marbling score; Warner-Bratzler shear force; and taste panel tenderness measured on steers were moderate to high (0.26 to 0.65), suggesting that selection for carcass and meat traits could be effective. Estimates of heritability for taste panel flavor and taste panel juiciness were low and negligible (0.05 and 0.01, respectively). Estimates of heritability from cow data over all ages and seasons were high for MW, AMW, and HT (0.52, 0.57, 0.71; respectively) and relatively low for BCS (0.16). Pairwise analyses for each female mature trait with each carcass trait were done with bivariate animal models. Estimates of genetic correlations between cow mature size and carcass composition or meat quality traits, with the exception of HCWT, were relatively low. Selection for cow mature size (weight and/or height) could be effective and would not be expected to result in much, if any, correlated changes in carcass and meat composition traits. However, genetic correlations of cow traits, with the possible exception of BCS, with HCWT may be too large to ignore. Selection for steers with greater HCWT would lead to larger cows.

Adipose Tissue↗

PubMed1997

Characterization of different biological types of steers (cycle IV): wholesale, subprimal, and retail product yields.

Carcass cut-out yields of 888 steers obtained from mating Hereford and Angus cows to Hereford or Angus (HA), Charolais (Ch), Gelbvieh (Gb), Pinzgauer (Pz), Shorthorn (Sh), Galloway (Gw), Longhorn (Lh), Nellore (Ne), Piedmontese (Pm), and Salers (Sa) sires were compared. Data were evaluated at constant age (426 d), carcass weight (324 kg), fat thickness (1.2 cm), fat trim percentage (23%), and marbling (Small(00)) end points. Piedmontese-sired steers excelled in total retail product and fat trim percentages at all slaughter end points except at the 23% fat trim end point. At an age end point, percentage of retail product was greater in steers sired by Continental European breeds (Gb, Ch, Sa, Pz; 63.3 to 65.5% at 0 cm trim) than in steers sired by British breeds (Sh, HA; 60.1 to 61.0%). Piedmontese-sired steers, which were expected to carry one copy of a major gene for muscle hypertrophy, had the highest (P < .05) retail product yields at an age end point (69.7%). At an age end point, although carcass weights were significantly heavier (P < .05) for Charolais-sired steers than for Piedmontese-sired steers, lean growth rate, as reflected by totally trimmed retail product at 426 d, was similar (P > .05) for Piedmontese and Charolais-sired steers. Differences among sire breeds were small for retail product percentage at marbling, fat thickness, and fat trim end points. Ranking of sire breeds for age-constant weight of retail product was as follows: Ch, Pm, Gb, Sa, Ne, Pz, HA, Sh, Gw, and Lh. Sire breed differences in wholesale and subprimal cut yields were similar to total retail product differences. Piedmontese-sired steers produced the most muscular, leanest, and highest-yielding carcasses, and HA- and Sh-sired steers produced the fattest, lowest-yielding carcasses.

Analysis of Variance↗

PubMed1996

Prediction of breeding values for tenderness of market animals from measurements on bulls.

Data were tenderness measures on steaks from 237 bulls (Group II) slaughtered after producing freezable semen and on 1,431 related steers and heifers (market animals, Group I) from Angus, Hereford, Pinzgauer, Brahman, and Sahiwal crosses from the Germ Plasm Evaluation project at the U.S. Meat Animal Research Center. Tenderness was assessed through Warner-Bratzler Shear Force (SF), taste panel tenderness (TPT), marbling score (MS), and myofibrillar fragmentation index (MFI). For all traits, as fraction Bos indicus inheritance increased, implied tenderness decreased. Heritability estimates were generally not significantly different from zero. Genetic correlations generally indicated favorable associations among the traits. The range in predicted breeding values of bulls for market animal tenderness was small and from -.34 to .32 kg for market animal shear force. Because of low estimates of heritability for SF or TPT, results from this experiment indicate that selection based on tenderness of steaks sampled from intact or late castrate males slaughtered following collection of freezable quality semen would not be very effective in improving average tenderness of steaks from steers of heifer progeny. If a mean of heritability estimates reported in the literature of .27 for shear value was assumed for market steer and heifer progeny instead of .02 as found in the present study, then selection based on estimates of shear force in young bulls would be relatively more effective in improving shear force of market progeny.

Animals↗

PubMed1996

Characterization of biological types of cattle (Cycle IV): carcass traits and longissimus palatability.

Carcass and longissimus thoracis palatability traits from 888 steers obtained from mating Hereford and Angus cows to Hereford or Angus (HA), Charolais (Ch), Gelbvieh (Gb), Pinzgauer (Pz), Shorthorn (Sh), Galloway (Gw), Longhorn (Lh), Nellore (Ne), Piedmontese (Pm), and Salers (Sa) sires were compared. Data were adjusted to constant age (426 d), carcass weight (324 kg), fat thickness (1.2 cm), fat trim percentage (23%), and marbling (small00) end points. At a constant age of 426 d, carcasses from Ch steers were heaviest (P < .05) and Gw and Lh carcasses were lightest (P < .05). Adjusted fat thickness was greatest (P < .05) on carcasses from HA and least (P < .05) on carcasses from Ch, Gb, Lh, and Pm steers. USDA numerical yield grades were lowest (P < .05) for carcasses from Pm and highest (P < .05) for carcasses from HA, Ne, and Sh steers. Marbling scores were highest (P < .05) for carcasses from HA, Pz, and Sh and lowest (P < .05) for carcasses from Ch, Ne, and Pm steers. Longissimus thoracis from Pz had a lower (P < .05) shear force than that from all other breeds except HA, Gb, and Pm. Longissimus thoracis of carcasses from Ne steers was least (P < .05) tender. Adjustment of traits to various end points resulted in some changes in sire breed differences depending on the end point and the trait being considered but had little effect on palatability traits. Carcasses from Pm-sired steers provided the most desirable combination of carcass and longissimus palatability traits.

Analysis of Variance↗

PubMed1995

Growth, digestive capability, carcass, and meat characteristics of Bison bison, Bos taurus, and Bos x Bison.

Three experiments involving 39 Bos taurus, 14 Bison bison, and 20 Bos x Bison fed diets differing in proportions of roughage and concentrate to evaluate growth, digestive capability, carcass, and meat characteristics are reported. Bos taurus consumed more (P < .05) feed per day and gained more (P < .05) rapidly than bison or Bos x Bison except during a period of extremely cold weather. Efficiency of gain was similar for all species types. There was no tendency for bison or Bos x Bison to gain more than Bos taurus on the higher-roughage diets. Bison and Bos x Bison had higher (P < .10 to .01) digestion coefficients for all components evaluated (i.e., DM, CP, GE, NDF,hemicellulose, and cellulose). Species x diet interactions were not significant, indicating that the higher digestion coefficients of bison were not specific to high-roughage diets. Bison and their hybrids had more (P < .05) lean meat and less (P < .01) fat trim in all wholesale cuts except the chuck and rib cuts. Fat thickness at the 12th rib of bison was higher (P < .01) than that of Bos taurus because most of the carcass fat of bison is located over the thoracic area. Bison and Bos x Bison had higher (P < .01) dressing percentages and a lower (P < .01) proportion of their carcass in the hindquarter than Bos taurus. Shear force and sensory tenderness scores indicated bison were more (P < .05) tender and had a flavor different (P < .01) from that of Bos taurus. Bison and Bos x Bison had more (P < .01) cholesterol in the longissimus muscle and less (P < .05) in the subcutaneous fat than Bos taurus. Bison had a lower (P < .01) percentage of white and higher percentage of intermediate muscle fibers than Bos taurus with essentially no difference in percentage of red fibers.

Animals↗

PubMed1993

Effect of castration on myofibrillar protein turnover, endogenous proteinase activities, and muscle growth in bovine skeletal muscle.

The effect of castration on endogenous proteinase activity and myofibrillar protein turnover was investigated in cattle. Six each of MARC III composite bulls and steers weighing approximately 210 kg were given ad libitum access to a typical growing diet. At 0, 42, 84, 126, and 168 d, two consecutive 24-h urine samples were obtained. Urine was analyzed for N tau-methylhistidine (N tau MH) and creatinine. Following slaughter after 170 d on feed, a longissimus muscle sample was removed immediately from each carcass for quantification of mu-calpain, m-calpain, calpastatin, cystatin(s), cathepsin B, and cathepsin B + L activities. Bulls were heavier (P < .05) at 126 and 168 d and more efficient (P < .05) in conversion of feed to gain at 84 and 168 d than were steers. Compared with steers, bulls excreted less (P < .05) N tau MH at 84, 126, and 168 d and displayed lower (P < .05) fractional degradation rates (FDR) at all sample times. No differences (P > .05) in calpain or cathepsin activities were observed between bulls and steers. However, muscle from bulls had greater (P < .05) activities of calpastatin and cystatin(s) than that from steers. A negative relationship existed between d-168 FDR and calpastatin (r = -.72; P < .05) and cystatin (r = -.62; P < .05) activities. These results indicate that decreased FDR of skeletal muscle from growing bulls contributes to their greater efficiency of growth and could be related partially to cystatin-mediated cathepsin activity and(or) calpastatin-mediated calpain activity.

Animals↗

PubMed1993

Meat tenderness and the calpain proteolytic system in longissimus muscle of young bulls and steers.

The objectives of this study were to examine the effects of castration on the calpain proteinase system (mu-calpain, m-calpain, and calpastatin) activities and meat tenderness. Six each, MARC III bulls and steers were slaughtered at approximately 12 mo of age. Longissimus muscle samples were obtained for determining myofibril fragmentation index, Warner-Bratzler shear force, and sensory panel evaluation at 1, 7, and 14 d postmortem, and mu- and m-calpain and calpastatin activities at 24 h postmortem. Bulls produced leaner carcasses with lower (P < .05) quality grades than did steers. Meat from bulls had higher (P < .05) shear force values than meat from steers; however, sensory panelists were unable (P > .05) to detect differences in tenderness or other sensory traits between bulls and steers. Activities of mu- and m-calpain were not affected (P > .05) by castration; however, calpastatin was higher (P < .05) in muscles from the bull carcasses. Lower (P < .05) myofibril fragmentation index values indicate that less proteolysis occurred in muscle from bulls than in muscle from steers during the first 7 d postmortem. Greater calpastatin 24-h activity may be associated with the increased shear force of meat from bulls.

Animals↗

PubMed1992

The effect of postmortem time of injection and freezing on the effectiveness of calcium chloride for improving beef tenderness.

Three experiments were conducted to determine the effect of freezing and time postmortem on the effectiveness of injecting CaCl2 to tenderize beef. In Exp. 1, longissimus muscle treatments included 1) control 0 h, 2) CaCl2-injected 0 h, 3) control 24 h, and 4) CaCl2-injected 24 h. Injection consisted of .3 M CaCl2 at 10% by weight. Injecting CaCl2 at 24 h postmortem reduced (P < .05) shear force requirements compared with the 24 h control but did not (P < .05) tenderize meat as much as injecting at 0 h. In Exp. 2, longissimus muscle treatments included the following: 1) aged 2 d; 2) aged 7 d; 3) frozen d 1, thawed, aged 6 d; 4) CaCl2-injected d 1, aged 6 d; 5) frozen d 1, thawed, CaCl2-injected, aged 6 d; and 6) CaCl2-injected d 1, frozen, thawed, aged 6 d. Injection alone at d 1 or freezing, then thawing and injecting resulted in the lowest (P < .05) shear force requirements. In Exp. 3, longissimus muscle treatments included the following: 1) aged 1 d; 2) aged 7 d; 3) CaCl2-injected 0 h, aged 7 d; 4) CaCl2-injected d 1, aged 6 d; 5) frozen d 1, thawed, aged 6 d; and 6) frozen, thawed, CaCl2-injected, aged 6 d. Both d-1 injection alone and freezing, thawing, then injecting resulted in meat with shear force requirements similar to those of 0-h injected meat. The effect of treatments on cooking loss was inconsistent. Treatments that reduced shear force also reduced (P < .05) calpain and calpastatin activity proportionately.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Estimated breeding values for meat characteristics of crossbred cattle with an animal model.

Longissimus muscle area, shear force measure, and sensory panel scores for flavor, juiciness, and tenderness, and marbling score were obtained from 682 steer carcasses, resulting from crosses among five Bos taurus and Bos indicus breeds. The single-trait model used included birth year and as covariates breed fractions, weaning age, and days on feed. The numerator relationship matrix was for 1,350 animals (682 steers, 74 pure breed and 52 F1-cross sires and 542 dams). The coefficient matrix was inverted to examine standard errors of prediction. Estimated breeding value is the sum of the estimate of genetic deviation and the weighted (fractions) sum of estimates of breed effects. Heritabilities used in estimating breeding values were .62, .06, .05, .11, .05, and .43 for longissimus muscle area, shear force, flavor, juiciness, tenderness, and marbling score. Sires within a breed or crossbred group tended to rank similarly due to large differences among breed effects (e.g., the six Sahiwal sires ranked in the highest six places for shear force). These results illustrate that for traits with large breed differences, selection of the proper breed should be done before selection within that breed.

Animals↗

PubMed1991

An evaluation of tenderness of the longissimus muscle of Angus by Hereford versus Brahman crossbred heifers.

Postmortem aging of carcasses obtained from Angus-Hereford (n = 8) and 5/8 Brahman crossbred (n = 8) heifers was investigated to determine the cause of variation in meat tenderness. Raw longissimus muscle (LM) myofibril fragmentation index was lower and cooked LM Warner-Bratzler shear force was greater for the 5/8 Brahman crossbreds (P less than .05). The activities of calcium-dependent protease (CDP) -I and -II were not affected (P greater than .05) by breed; however, CDP inhibitor activity was higher (P less than .05) in the 5/8 Brahman carcasses. The activities of cathepsins B and B + L were not affected by breed or postmortem storage time (0, 1, 3, 7 or 14 d). Hereford-Angus carcasses were fatter opposite the 12th rib and had higher USDA yield grades and marbling scores (P less than .05). Hereford-Angus crossbreds had less dark, coarse band formation around the exterior of the LM and lighter, finer-textured lean (P less than .05). Cooking loss (%) and cooking rate (g/min) were not affected by breed or postmortem aging (P greater than .05). The increased toughness in the 5/8 Brahman carcasses may be due to increased CDP inhibitor activity.

Animals↗

PubMed1991

Factors influencing difficulty of removing pelts from lamb carcasses.

Forty-eight Suffolk x white-faced ram and wether lambs approximately 5, 7, or 9 mo of age were slaughtered to evaluate the effects of age and gender on difficulty of pelt removal, pelt damage, and leg damage. A commercial belt-type pelt puller and a scale that recorded force required to remove the pelt from the thickest part of the legs was used as lambs hung suspended from their front legs. Rams required more force (P less than .05) to remove the pelt than wethers, and the difference between genders became larger as age increased. Neither pelt damage due to grain crack nor leg damage judged by amount of fell and fat removed by the pelt puller changed with age. Rams possessed thicker pelts (P less than .05) than wethers; this plus a greater amount of collagen crosslinking in ram skins could be responsible for the slightly smaller amount of grain crack observed in ram pelts. Factors involved in difficulty of pelt removal in ram lambs included age, splenius weight, and overall maturity. Difficulty of pelt removal in wether lambs was best predicted by including age and splenius weight in the model. These data tend to support packers' common practice of discounting rams over 5 mo of age because rams develop masculine characteristics and become harder to dress with increasing age.

Age Factors↗

PubMed1991

Effect of ractopamine on growth, carcass traits, and fasting heat production of U.S. contemporary crossbred and Chinese Meishan pure- and crossbred pigs.

Twenty-four U.S. crossbred (Duroc x White composite; D x Wc; 83.9 kg), 24 purebred Meishan (M; 59.4 kg), and 24 Meishan x White composite crossbred (M x Wc; 83.4 kg) barrows were allotted within genotype to a 16% CP corn-soybean meal diet or this basal diet + 20 ppm of ractopamine and allowed ad libitum access to feed for 52 d. No genotype x ractopamine interactions were detected (P greater than .05) in pigs for growth, lean cuts, ham and loin characteristics, leaf fat and visceral organ weights, fasting whole-animal heat production, and carcass traits except longissimus muscle area (LMA). The LMA was increased by ractopamine in D x Wc and M x Wc pigs (P less than .05) but not in M pigs. Compared with D x Wc and M x Wc pigs, M pigs had lower ADG, ADFI, and gain to feed ratio (G/F), shorter carcasses, and lower dressing percentage, LMA, predicted amount of muscle, weights of trimmed picnic, loin, and ham cuts, percentage of ham lean, and CP in ham lean, but heavier liver, kidneys, pancreas, and entire gastrointestinal tract with greater percentage of ham fat and ham bone (P less than .05). The M x Wc pigs had lower ADG, G/F, dressing percentage, LMA, amount of muscle, weights of trimmed cuts, and percentage of ham lean but heavier lungs, pancreas, stomach, and large intestine than did D x Wc pigs (P less than .05). Supplemental ractopamine increased ADG, G/F, dressing percentage, amount of muscle, trimmed loin weight, percentage of ham lean, and CP in ham lean and decreased weights of heart, lungs, kidneys, and pancreas in pigs (P less than .05). Neither genotype nor ractopamine had any effect on 4- to 24-h postprandial whole-animal heat production of pigs (P greater than .05). These results indicate that ractopamine will improve growth performance and carcass leanness in pure- and crossbred Meishan pigs.

Animals↗

PubMed1991

Effects of calcium chloride injection and hot boning on the tenderness of round muscles.

Two experiments were conducted to determine the effect of CaCl2 injection on round muscles obtained from Bos indicus bulls and late-castrate steers. In Exp. 1, the biceps femoris (BF) muscle from the left side of each of 15 bull carcasses was injected within 30 min postexsanguination with .3 M CaCl2 at 10% by weight while either intact (n = 8) on the carcass or after hot boning (n = 7). The right sides served as controls. In Exp. 2, the semimembranosus (SM) muscles from the carcasses of nine steers (castrated at 16 mo of age) were hot-boned within 30 min postexsanguination and one-half were injected with CaCl2 as described above. Hot boning had no effect (P greater than .05) on shear force values. Calcium chloride injection dramatically reduced shear force requirements at 1, 8, and 14 d postmortem compared with noninjected controls in both experiments. Cooking traits of the SM muscle were not affected (P greater than .05) by CaCl2 injection. However, BF muscles injected with CaCl2 required more (P less than .05) time to cook and had greater (P less than .05) cooking losses than BF controls. Calcium chloride injection of prerigor round muscles reduced aging time needed for normal tenderization to 1 d postmortem. Hot boning was successfully used in conjunction with CaCl2 injection to facilitate the injection process.

Abattoirs↗

PubMed1991

Postmortem proteolysis in longissimus muscle from beef, lamb and pork carcasses.

Postmortem proteolysis in skeletal muscle and factors affecting this process were examined in pork, lamb and beef longissimus muscles (LM) to determine the cause of differences in meat tenderness among these species. Fat thickness differed among species in the following order: pork greater than beef greater than lamb. The following patterns were observed for rate of temperature and pH decline: lamb greater than pork greater than beef and pork greater than beef greater than lamb, respectively. At 1 d postmortem, pork was the most tender, followed by beef and lamb, respectively. Between 1 and 14 d of postmortem storage, lamb LM was the most improved in tenderness, followed by beef and pork, respectively. Species did not differ (P greater than .05) in LM collagen solubility. Pork LM from fed pigs had the highest (P less than .05) level of cathepsins B + L and cystatin(s) activities, whereas no differences (P greater than .05) were observed among the species for cathepsin B activity. The lowest (P less than .01) Ca2(+)-dependent protease (CDP)-II and CDP inhibitor activities were observed in pork LM. Beef LM had the highest CDP inhibitor activity (P less than .05) but was intermediate in CDP-II activity. No differences were observed among species for CDP-I activity. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrils isolated at 0, 1 and 14 d postmortem indicated that by d 1, desmin hydrolysis was most extensive in pork muscle, followed by lamb and beef.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1990

Use of a bacteriocin produced by Pediococcus acidilactici to inhibit Listeria monocytogenes associated with fresh meat.

A bacteriocin produced by Pediococcus acidilactici had an inhibitory and bactericidal effect on Listeria monocytogenes associated with fresh meat. MICs were significantly lower than minimum killing concentrations. When meat was inoculated with L. monocytogenes, the bacteriocin reduced the number of attached bacteria in 2 min by 0.5 to 2.2 log cycles depending upon bacteriocin concentration. Meat treated initially with the bacteriocin resulted in attachment of 1.0 to 2.5 log cycles fewer bacteria than that attained with the control. The bacteriocin, after 28 days of refrigerated storage on meat surfaces, was stable and exhibited an inhibitory effect on L. monocytogenes.

Animals↗

PubMed1990

Effect of ovariectomy and ovariectomy with ovarian autotransplantation on feedlot performance and carcass characteristics of heifers.

Feedlot growth performance and carcass characteristics were examined in 96 crossbred heifers of continental breeding. Heifers were assigned to four treatment groups: intact control, sham ovariectomized, ovariectomized, and ovarian autografted. Ovarian autografted heifers were bilaterally ovariectomized via a left flank incision and one ovary was bisected sagittally and implanted in the musculature of the flank. Animals were fed a diet based on corn silage and were slaughtered at a weight of about 450 kg. There was no effect of treatment on feedlot performance or objectively measured carcass traits. However, carcasses of ovariectomized and ovarian autografted heifers had lower maturity scores than carcasses of the intact and sham-ovariectomy heifers. Blood samples were collected monthly throughout the study. Progesterone concentrations in these samples indicated that approximately 20% of the ovarian autografted heifers exhibited ovarian cyclicity. Examination of the transplanted ovaries at slaughter indicated that approximately 20% of the transplanted ovaries were resorbed. Cavitated, fluid-filled, thick-walled structures that were considered to be luteinized follicles were the most prominent structures found on the transplanted ovary; these were found in one-third of the ovarian autografted heifers. These results indicate that an ovary transplanted to the musculature can remain viable; however, its physiological function is disrupted and it does not affect rate or efficiency of gain or carcass composition compared to ovariectomized heifers.

Animals↗

PubMed1990

Effects of high-temperature conditioning on enzymatic activity and tenderness of Bos indicus longissimus muscle.

We studied the effects of high-temperature conditioning (HTC) on beef longissimus (LM) and semitendinosus muscles. Eleven 5/8 Sahiwal x Angus, Hereford or Angus x Hereford crosses (seven heifers and four steers) were slaughtered. Alternate carcass sides were held at 22 +/- 3 degrees C for 6 h, then chilled at -1 degree C for 18 h. The opposite, control (C) sides were chilled at -1 degree C for 24 h. Samples were removed only from the LM at various times to determine calcium-dependent protease (CDP) and CDP inhibitor (INH) activity, cathepsins B and B + L activity, shear-force, sensory panel traits, myofibrillar fragmentation index (MFI) and sarcomere length. Results were analyzed by least squares procedures; our model included fixed effects of temperature, sex and their interaction. The LM temperature remained higher (P less than .01) for the HTC treatment at 3, 6, 9 and 12 h postmortem. In addition, HTC increased the rate of pH decline which resulted in pH differences (P less than .01) at 6, 9 and 12 h. At d 1, LM steaks had lower (P less than .05) shear forces (8.3 vs 9.6 kg) from HTC than C carcasses. At d 14, LM shear forces tended (P = .13) to be lower for HTC (6.9 kg) than for C (7.7 kg) carcasses. At, 3, 7 and 14 d, MFI for LM were greater (P less than .07) for the HTC steaks. However, by 6 h postmortem, INH activity had decreased (P less than .10) 35% in HTC samples, but no change had occurred in C samples (P less than .10).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗