Journal of Animal Science

Lofgreen, G., P.;Dunbar, J., R.;Addis, D., G.;Clark, J., G.

doi: 10.2527/jas1975.4151256xpmid: N/A

Summary Three-hundred-ninety-five calves subjected to the stresses of marketing and shipping were used to test various energy levels in receiving rations. Rations containing 38, 46, 50 and 54 megcal of NEg per 100 lb (.84, 1.01, 1.10 and 1.19 megcal per kilogram) were compared. The rations contained 20, 55, 72 and 90% concentrates. Performance improved with increasing concentrate or energy level until the 72% level was reached. Calves fed the 90% concentrate level were slower starting than those fed the 72% ration although after the first week the performance was good. Because of the disease stress the first week, the 90% ration is not recommended. The majority of the first treatments of sick calves occurred during the first 7 days following arrival. When receiving calves on the 72% concentrate ration, no advantage was found in providing free access to long stem alfalfa hay. This content is only available as a PDF. Author notes 2 Department of Animal Science. 3 Extension Livestock Specialist, Davis, California. 4 Farm Advisor, Agricultural Extension Service, Riverside County. 5 Veterinarian, Brawley, California. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Siers, David, G.

doi: 10.2527/jas1975.4151266xpmid: N/A

Summary Sixty-six Yorkshire pigs consisting of 21 boars, 22 barrows and 23 gilts were individually penned and fed a ration containing chromic oxide. Digestion coefficients for the total ration (GPT), the protein (GPP) and the fat (GPF) were calculated for each pig at three different weights. The pig's ability to digest the ration and its components was influenced significantly by the size (age) of the pig but not by sex. Significant litter effects were found for GPT and GPP but not for GPF. The intraclass correlations among full-sibs for GPT, GPP and GPF were .31, .27 and .14-, respectively. The correlations among GPT, GPP, GPF, feed efficiency, rate of gain and feed consumption indicate that fast growing pigs eat more feed per day, require less feed per unit of gain and have lower digestion coefficients for the complete ration, protein and fat. The correlations of backfat, longissimus muscle measurements and ham and loin percentage with GPT, GPP and GPF indicate that the, pigs that have the highest percent muscle are the pigs that more completely digest and absorb the ration. This content is only available as a PDF. Author notes 2 Present address: Shell Development Company, Biological Sciences Research Center, P. O. Box 4248, Modesto, California, 95352. 3 Department of Animal Science. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Cundiff, Larry, V.;Gregory, Keith, E.;Long, Charles, R.

doi: 10.2527/jas1975.4151270xpmid: N/A

Summary Birth and livability data on 995 calves born, weaning data on 915 calves and carcass data on 817 calves produced in two calf crops were studied. Calves were sired by 51 bulls from 18 Angus herds and 44 bulls from 18 Polled Hereford herds (two to four sires sampled/herd) through AI matings to Hereford and Angus cows at the U.S. MARC. Estimates of genetic variance did not differ significantly between breeds. From pooled analyses, effects of herd origin of sires were significant for birth weight, 200-day weight, postweaning average daily gain, 452-day weight, marbling, final carcass grade and carcass conformation grade. Effects of sire/herd were highly significant for postweaning average daily gain, 452-day weight, carcass conformation, final grade, marbling, fat thickness, longissimus muscle area and significant for estimated cutability. Genetic variance components for herds and sires/herd were used to compute the intraherd correlation of individual breeding values. Relatively higher correlations for growth traits (averaging .51) than for carcass traits (averaging .16) indicate that selection pressures and responses have been more diverse, among herds, for growth traits than for carcass traits. This content is only available as a PDF. Author notes 3 U.S. Meat Animal Research Center, North Central Region, Agricultural Research Service. 4 Present Address: Department of Animal Science, Texas A&M University, College Station. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Mowafy,, M.;Cassens, R., G.

doi: 10.2527/jas1975.4151281xpmid: 1194118

Summary Skin samples were removed from several body regions of the pig by biopsy or during the slaughter process and were fixed, processed for paraffin embedding and sectioned at 6 to 8 µm thickness. Several stains were used to emphasize the different structures of the organ. Microscopic observations revealed that the epidermis of the pig was rather rough and characterized by a pattern of ridges. Epidermal thickness varied greatly amongst different body regions. The shoulder and the snout possessed deep patterns of ridges, while the dorsum and the hip were characterized by a thin pattern. The dermis consisted mainly of coarse collagen fibers oriented both perpendicular and parallel to the surface. Elastic fibers permeated the entire dermis and were concentrated around the hair follicles and in the papillary layer around the interpapillary pegs. Bulbs of the growing hair follicles were located primarily in the relatively thick hypodermis. Most of the secretory coils of the sweat glands were also located in the hypodermis and their ducts opened independently near the orifice of the hair follicles with which they were associated. Sebaceous glands were rather rudimentary and were mainly found in conjunction with hair follicles. Hair follicles were generally arranged in groups of three (triad). This content is only available as a PDF. Author notes 2 Department of Meat and Animal Science. Copyright 1975 by American Society of Animal Science American Society of Animal Science

Mowafy,, M.;Cassens, R., G.

doi: 10.2527/jas1975.4151291xpmid: N/A

Summary The effects of several scalding methods were studied. Skin strips from pigs were obtained immediately after exsanguination and were scalded in five different media at 56, 58 and 60 C for 2, 4, 6 and 8 minutes. Upon completion of scalding, the plucking force of hairs was determined. Skin samples were also procured and processed for microscopic studies. The use of different scalding media did not significantly affect the plucking force or the microstructure of the skin. Plucking force, however, significantly decreased as both scalding time and temperature increased. The use of sodium borohydride (a common depilator) aided in the faster sloughing off of the stratum corneum at relatively low temperatures. Scalding at temperatures higher than 58 C for periods longer than 6 min had, generally, a detrimental effect on the skin quality. Severe loss of the grain layer and a disintegration of the hair shafts inside their follicles were noticed when samples were over-scaled. According to the microscopic observations on skin strips scalded at 60 C for 4 min (recommended by the American Meat Institute Foundation), the samples were considered overscalded. This content is only available as a PDF. Author notes 2 Department of Meat and Animal Science. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Skelley, G., C.;Borgman, R., F.;Handlin, D., L.;Acton, J., C.;McConnell, J., C.;Wardlaw, F., B.;Evans, E., J.

doi: 10.2527/jas1975.4151298xpmid: N/A

Summary Four treatments with 14 swine per treatment were conducted during the growth period. Treatment 1 was a typical corn-soybean meal ration, whereas treatments 2, 3 and 4 employed barley in combination with 14, 22 and 30% roasted soybeans, respectively. Dressing percentages, muscling, backfat and final grade were similar among treatment groups. The carcasses from treatment 1 produced a slightly firmer type of fat and lean. There were no significant differences in longissimus muscle area or percentages of cuts. The linoleic acid content of the meat and backfat increased in direct proportion to the amount of whole soybeans in the ration. The percentage of linoleic acid ranged from 5.1 to 10.6% of total fat in raw lean meat. An increase in linoleic acid from 11.2 to 21.3% was noted in the backfat. Whole soybeans in swine rations produced carcasses of acceptable quality and cuts which have a greater percentage of linoleic acid. This may be of advantage to a certain portion of our population interested in increasing the amount of polyunsaturated fat in their diet. In fact, the amount of linoleic acid in the final product can actually be changed by changing the level of roasted soybeans in the ration. A greater percentage of unsaturated fat has not been proven to be desirable; however, it should be known that such a product can be adequately produced, processed, stored and consumed. This content is only available as a PDF. Author notes 2 Department of Animal Science. 3 Department of Food Science. 4 Appreciation is expressed to J. T. Gillingham, Agriculture Chemical Services and W. E. Johnston, Experimental Statistics. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Davis, G., W.;Smith, G., C.;Carpenter, Z., L.;Cross, H., R.

doi: 10.2527/jas1975.4151305xpmid: N/A

Summary Scores were assigned for marbling, color, firmness and structure of muscle surfaces at the blade end, 10th rib, last rib, fifth lumbar vertebra and sirloin end of 403 wholesale pork loins. Chops from a section of the loin between the 10th and last ribs were cooked to an internal temperature of 75 C and rated by a trained six-member sensory evaluation panel. Quality scores at the five anatomical locations as well as chemical and physical measurements from the longissimus muscle were related to cooking losses and palatability attributes. Marbling, color, firmness and muscle structure, evaluated at all five loin interfaces, were related (P<.01) to ratings for juiciness and overall satisfaction. Multiple regression equations combining the four quality scores at the blade end, 10th rib and sirloin end, respectively, accounted for .5, 19.7, 8.1 and 15.6; 1.8, 28.2, 12.0 and 24.1; 2.0, 23.6, 9.2 and 15.5% of the variability in ratings for flavor, juiciness, tenderness and overall satisfaction, respectively. Stratification according to marbling, color or muscle structure segmented loins into groups which differed significantly in juiciness, tenderness, overall satisfaction and cooking loss percentages, but did not identify loins which differed significantly in flavor intensity. Marbling, color and/or structure scores assigned at the blade or sirloin end of the loin (if industry practice necessitates grading at one end or the other) can be used to segment wholesale pork loins into quality groups for grade identification purposes. This content is only available as a PDF. Author notes 2 Employed by the Standardization Branch, Livestock Division, Agriculture Marketing Service, U.S.D.A. at the time of this study. Present Address: Meat Science Research Laboratory, Agricultural Marketing Research Institute, A.R.S., U.S.D.A., Beltsville, Maryland. 3 Department of Animal Science, Meats and Meat Chemistry Section. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Campion, D., R.;Olson, J., C.;Topel, D., G.;Christian, L., L.;Kuhlers, D., L.

doi: 10.2527/jas1975.4151314xpmid: 352

Summary The purpose of this investigation was to study the respiratory functions of skeletal muscle mitochondria isolated from 12 pigs of similar breeding that were equally divided as stress susceptible (SS) and stress resistant (SR), depending on their response to halothane (Fluothane®) anesthesia. Skeletal muscle samples were collected by biopsy 2 to 4 weeks before slaughter, immediately post-mortem and 3 hr post-mortem. As the muscle pH decreased from a mean value of 7.08 to 6.39, state 3 and state 4 respiration, respiratory control index and ADP/O ratio were reduced. No mitochondrial respiratory activity was observed below muscle pH 5.90. Statistical analysis was confined to biopsy and immediately post-mortem values because of lack of respiratory activity in all mitochondrial preparations from SS pigs at 3 hr post-mortem. For the remaining two sampling periods, no significant interactions were observed between time of sampling and type of pig for any of the respiratory traits measured. Type of pig did not show a significant relationship between state 3, state 4 or the ADP/O ratio when biopsy values were compared. Therefore, the mitochondrial characteristics studied do not appear to be involved in the etiology of the porcine stress syndrome. When muscle tissue was obtained immediately after death, the stress-susceptible pigs had significantly (P<.01) lower state 4 values, and the state 3 values were approaching significance (P<.07). The respiratory response probably was caused by a significantly (P<.01) lower muscle pH for the stress-susceptible pigs when evaluated immediately post-mortem. This content is only available as a PDF. Author notes 2 Present address: U.S. Meat Animal Research Center, A.R.S., U.S.D.A., Clay Center, Nebraska 68933. 3 Research supported by the Iowa Agriculture and Home Economics Experiment Station and by A.R.S., U.S.D.A. Cooperative Agreement No. 12-14-100-11185-44. Appreciation is expressed to Ayerst Laboratory for providing for Fluothane. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Cross, H., R.;Smith, G., C.;Carpenter, Z., L.;Kotula, A., W.

doi: 10.2527/jas1975.4151318xpmid: N/A

Summary A total of 403 butcher hog carcasses were selected from two commercial firms or from the Meats Laboratory at Texas A&M University. These carcasses, chosen to vary widely in muscling and fatness, were cut and trimmed according to procedures developed by U.S.D.A. and Texas A&M University personnel. Among measures of fatness, fat depth over the longissimus muscle (10th or last rib) was most closely associated with yields of lean cuts and total lean. Neither length nor weight of carcass was associated with more than 10% of the variability in cutting yields. Among measures of muscling, loin eye area (longissimus muscle area at the 10th or last rib) and lumbar lean depth were most highly correlated with percentages of trimmed four lean cuts (.64, .66 and .49, respectively). Some advantage in accuracy of lean yield estimation was noted in favor of the use of overall U.S.D.A. muscling scores as compared to either of the ham evaluations (rear or stifle views). Unadjusted and subjectively adjusted (by use of other visual indices of carcass fatness) backfat thickness measures were not different for predicting percentages of regular trimmed four lean cuts (−.88 and −.89). An equation combining measures of average backfat thickness, carcass length and U.S.D.A. muscling score (overall evaluation) was associated with 83.4% of the observed variability in percentage of regular trimmed four lean cuts. A change of .25 cm (.1 in) in average backfat thickness was equivalent to a change of one full U.S.D.A. muscling score in its effect on percentage yields of regular trimmed four lean cuts. Fat depth over the longissimus muscle at the 10th rib, in combination with carcass length and longissimus area at the 10th rib most accurately predicted percentages of total separable muscle from the four lean cuts (R2 × 100 = 89.5%). This content is only available as a PDF. Author notes 1 Employed by the Standardization Branch, Livestock Division, Agriculture Marketing Service, U.S.D.A. at the time of this study. Present address: Meat Science Research Laboratory, Agricultural Marketing Research Institute, A.R.S., U.S.D.A., Beltsville, Maryland. 2 Meats and Meat Chemistry Section, Department of Animal Science, Texas A&M University, College Station 77843. 3 Meat Science Research Laboratory, A.R.S., U.S.D.A., Beltsville, Maryland. Copyright 1975 by American Society of Animal Science. American Society of Animal Science