Journal of Animal Science

Oliver, W., M.

doi: 10.2527/jas1975.414999xpmid: N/A

Summary A 140-day grazing trial was conducted to determine the effects of various levels of monensin on gains made by steer calves and yearlings while grazing Coastal bermudagrass pasture. Cattle on all treatments were grazed on Coastal bermudagrass forage at a stocking rate of 2.5 head per acre (6.2 steers per hectare). Corn, yellow, grnd., pelleted, 4 02 992 (ground, pelleted corn) was fed at a rate of 2 lb (908g) per head daily as a carrier for the appropriate monensin levels. The treatments were no corn, corn only, and corn plus 25, 50, 100, or 200 mg monensin per head daily. Each treatment was replicated twice. Ten cattle, with equal numbers of steer calves and yearling steers, were grazed in each replicate. The cattle were rotated among pastures within each set of replicates at 7-day intervals. Cattle on all levels of monensin produced larger (P<.05) weight gains than the control cattle. Animals fed corn with no monensin performed better than those on forage only. Growth rates of the steers receiving monensin increased as the drug level increased through 100 mg per head daily. Cattle fed the 200 mg level of monensin gained only slightly, but significantly, more than those on the 25 mg level. This content is only available as a PDF. Author notes 1 Gratitude is expressed to Eli Lilly and Company, Greenfield, Indiana for their support of this study and to Dr. Ben F. Schlegel, D.V.M. of the Eli Lilly Company for his guidance in conducting the study. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Brown, M., A.;Frahm, R., R.

doi: 10.2527/jas1975.4141002xpmid: N/A

Summary Average daily feed consumption (ADFC) and feed efficiency (FE, gain/feed) from 21 to 42 days of age were measured in three groups of mice during generations 11 through 14 of a study designed to measure responses to selection for increased growth. One group was selected for increased 21-day weight (WWL), another group was selected for rapid gain between 21 and 42 days of age (ADGL), and a third group served as an unselected control (CL). Comparisons of FE and ADFC among WWL, ADGL and CL were very consistent over the four generations studied. As a result of the selection pressure applied, WWL and ADGL exceeded (P<.001) CL in 21-day weight by an average of 26.4% and 17.2%, respectively, and in 21 to 42-day ADG by 14.1% and 53.1%, respectively. The WWL and ADGL exceeded (P<.001) CL in ADFC by 17.4% and 26.9%, respectively. There was a 21.6% improvement (P<.001) in FE in ADGL over CL; however, WWL were 2.4% (P<.05)-less efficient than CL. Analyses of variance and covariance in CL provided estimates of genetic correlations between 21-day weight and ADFC of .37 ± .26, between 21-day weight and FE of –.48 ± .38, between 21 to 42-day ADG and ADFC of .55 ± .18 and between 21 to 42-day ADG and FE of .63 ±.16. This content is only available as a PDF. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Carroll, F., D.;Rollins, W., C.;Wagnon, K., A.;Loy, R., G.

doi: 10.2527/jas1975.4141008xpmid: N/A

Summary Thirty-two steers implanted with 36 mg of DES were compared with 32 untreated bulls as to growth rate and carcass characteristics. Of these animals, 17 paternal half-sib bull-steer pairs were used to compare eating quality. Average age at slaughter was approximately 14 months. Bulls produced more carcass weight per day of age than steers. Bull carcasses had less fat content, less marbling, larger rib-eye areas, darker meat, higher conformation grades and lower quality grades. Raw muscle samples from steers had more bound moisture while samples from bulls tended to have more free moisture, however, total moisture differences were nonsignificant. Total cooking losses were comparable in rib roasts from bulls and steers, but higher in top-round roasts from bulls. Cooked muscle samples from bulls and steers were comparable in shear value. For the more tender longissimus muscle, the taste panel scored steer meat higher than bull meat for tenderness, juiciness and flavor; but for less tender adductor and semimembranosus muscles there were no significant differences between buls and steers. This content is only available as a PDF. Author notes 1 Department of Animal Science. 2 Present Address: Department of Veterinary Medicine, University of Kentucky, Lexington 40506. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Overstreet, J., W.;Marple, D., N.;Huffman, D., L.;Nachreiner, R., F.

doi: 10.2527/jas1975.4141014xpmid: N/A

Summary Sixty market weight pigs were randomly assigned to one of six treatment groups: (I) unrestrained and unstunned control; (II) un-stunned but restrained; (III) immobilized with 90 volt a.c. current applied for 10 sec; (IV) stunned with 290 volt a.c. current applied for 2 sec; (V) stunned with captive bolt pistol; or (VI) immobilized by inhalation of a gas mixture of 75% CO2 and 25% air. Animals with a serum creatine phosphate kinase (CPK) level of less than 100 Sigma units/ml were selected for the study. Muscle biopsies collected 12 to 24 hr prior to slaughter and muscle samples taken 1 hr postmortem were analyzed for glucose-6-phosphate (G-6-P), adenosine triphosphate (ATP), creatine phosphate (CP), and lactate. Blood samples were obtained immediately prior to exsanguination for determination of blood pH, pCO2 and pO2. Muscle pH was determined at 1 and 18 hr postmortem. Group I had significantly (P<.05) higher muscle pH values and ATP levels at 1 hr postmortem and higher blood pH values than any other group. Group I had the higher blood pH values and Group VI had lower blood pH and higher pCO2 values than all other groups (P<.05). Groups I and IV had significantly higher CP levels 1 hr postmortem. There were no significant differences among other groups. The group of animals that was restrained, but not stunned had values similar to animals stunned by various methods. On the basis of this experiment it was recommended that the use of captive bolt pistol stunning should be discouraged. From a quality aspect the use of any stunning procedure is inferior to slaughtering without stunning. All other stunning methods affected postmortem metabolism similarly. This content is only available as a PDF. Author notes 1 Department of Animal and Dairy Sciences. 2 Departments of Physiology and Pharmacology and Animal Health Research. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

McConnel, J., C.;Skelley, G., C.;Handlin, D., L.;Johnston, W., E.

doi: 10.2527/jas1975.4141021xpmid: N/A

Summary Feedlot performance, carcass traits and the acceptability of fresh and stored pork samples were monitored on three replicates of pigs fed diets based on corn, wheat, milo or barley with soybean meal or roasted whole soybeans as the supplemental protein. The corn-based diets contained 16% crude protein for pigs weighing 21 to 57 kg and 14% crude protein from 57 to 101 kilograms. The other respective diets were formulated by substituting either wheat, milo or barley on a unit-for-unit basis for corn. Over the entire experimental period (21 to 101 kg), all treatments except barley-soybean meal promoted similar (P>.05) daily gains. Three significantly different (P<.05) groupings of treatments based on efficiencies of feed conversion were noted, which, ranked from most to least acceptable, were: corn and wheat containing either protein source; barley-roasted soybeans; and milo with either protein or barley-soybean meal. Data were also presented which indicated feedlot response to each treatment during both the growing and the finishing phases of production. This content is only available as a PDF. Author notes 2 Department of Animal Science. 3 Experimental Statistician. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Irvin, Keith, M.;Swiger, L., A.;Mahan, D., C.

doi: 10.2527/jas1975.4141031xpmid: N/A

Summary Four diets differing in crude protein level (12, 14, 16 and 18%) were fed throughout the growing-finishing period to pigs of two sexes (barrows and gilts) and three genetic groups (inbred and non-inbred Hampshires and Yorkshire × Hampshire crossbreds) to determine the influence of different dietary protein levels on feed, gain and carcass traits and to determine whether or not genetic differences are similarly influenced by the different protein levels. Gilts averaged higher in percent lean cuts and lower in growth rate than did barrows. A trend was observed in an increase of percent lean cuts as dietary protein level increased. Pigs fed the 14% and 16% levels of crude protein deposited a significantly larger amount of lean cuts per day on test than did those fed 12% or 18% protein. There was a significant increase in weight gain during both the first 42 days and the entire experimental period, in the first backfat layer during the first 42 days of the trial, and in the second backfat layer for the entire trial as a result of feeding 14% and 16% protein. This content is only available as a PDF. Author notes 2 Department of Animal Science, The Ohio State University, Columbus. 3 Department of Animal Science, Ohio Agricultural Research and Development Center, Wooster. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Baird, D., M.;McCampbell, H., C.;Allison, J., R.

doi: 10.2527/jas1975.4141039xpmid: N/A

Summary Two feeding trials from weaning to market weight were conducted with diets containing 4 and 8% crude fiber, 13 and 17% crude protein, and 2.87 and 3.48 Mcal/kg ME. The diets were computer formulated with pre-specified physical and quality requirements. A third feeding trial consisted of two levels of fiber (2.09 vs 8.87%) or bulk and two levels of energy (3.50 vs 2.94 Mcal/kg). Feeds in the third trial were used to determine volume of feed when wet or dry and the effect of volume and swelling capacity on feed consumption as related to bulk and energy content. Levels of crude fiber had no effect on growth rate provided energy density was adequate. The low fiber diets produced leaner carcasses than the high fiber diets, which may partially be due to added fats in the high fiber diets to equate energy levels. Crude protein level did not significantly increase growth rate when fed in diets of equal energy. This content is only available as a PDF. Author notes 1 Department of Animal Science and Agricultural Economics, respectively. 2 Present address: Department of Animal Science, University of Georgia, Athens 30602. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Mersmann, H., J.;Phinney,, G.;Brown, L., J.

doi: 10.2527/jas1975.4141048xpmid: 1176359

Summary Weaning of swine from a milk diet to a grain diet (lower fat and protein) yielded a decrease in the epinephrine-stimulated maximal lipolytic rate as well as the sensitivity to epinephrine in adipose tissue slices. The dietary influence was not solely the caloric or fat content of the diet since a similar lard-fortified diet with caloric and fat content similar to the milk yielded maximal lipolytic rates and epinephrine sensitivities that were intermediate between the milk diet and the grain diet. This content is only available as a PDF. Author notes 1 We would like to thank Dr. D. E. DeKay for the diet analysis and Mr. F. Gonsalves for the animal care. 2 Mailing Address: Shell Development Company, Biological Sciences Research Center, P. O. Box 4248, Modesto, California 95325. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Pond, W., G.;Walker, E., F.;Kirtland,, D.

doi: 10.2527/jas1975.4141053xpmid: 1176360

Summary One hundred and twenty mycoplasma pneumonia-free Yorkshire weanling pigs were divided randomly at 4 to 6 weeks of age into two groups fed a high (1.2% Ca, 1.0% P) Ca-P or normal (.5% Ca., .4% P) Ca-P corn-soybean meal-type diet to slaughter at approximately 90 kg live weight to determine the effect of dietary Ca-P level on weight gain, feed utilization and mineral content of bone and liver. There was no significant effect of Ca-P level on weight gain, efficiency of feed utilization or on retention of Ca, Co, Cu, Mg, Mn or Zn in bone or liver. Fe content of radius-ulna was decreased (P<.05) by high Ca. Ash content of radius-ulna from pigs fed 1.2% Ca-1.0% P tended to be higher than that of radius-ulna from pigs fed .5% Ca-.4% P. The lack of change in bone and liver concentrations of Mg, Co, Cu, Mn or Zn of pigs fed high Ca-P diets suggests that major changes in body stores of required trace elements are not likely as a result of high-Ca-P feeding if dietary levels are at or above N.R.C. recommendations. This content is only available as a PDF. Author notes 1 Department of Animal Science. 2 The authors are indebted to R. G. Eggert, American Cyanamid Co., Princeton, New Jersey for supplying the antibiotic supplement and to Priscilla Lawrence, Allan Chandler and Charles Avery for technical assistance and care of animals. Copyright 1975 by American Society of Animal Science. American Society of Animal Science

Woody, C., O.;Abenes, F., B.

doi: 10.2527/jas1975.4141057xpmid: 1176361

Summary Two-hundred and fifteen Holstein heifers were used in five experiments to evaluate the use of implants containing SC-21009 (17α-acetoxy -11β-methyl-19-norpreg-4-ene-3, 20-dione), a synthetic progestogen, alone or in combination with an injection of estradiol valerate for the control of estrus and ovulation. Two experiments were conducted using a 16-day implant period. In Experiment I, it was observed that heifers implanted 14 days postestrus and in heat within 5 days after implant removal had lower fertility (none of eight conceived to first service) than did those implanted 2 days postestrus and in heat within 5 days after implant removal (nine of 13 conceived to first service). In Experiment II, estrus and ovulation were not suppressed in most heifers implanted 14 days after estrus. This occurred during the winter with temperatures consistently below freezing. Three experiments with 9-day implant periods were conducted. In Experiment III, the number of heifers with an estrous cycle less than 17 days in length following implantation on days 2 through 11 was greater in heifers implanted with 12 mg SC-21009 than in heifers implanted with 6 milligrams. In Experiment IV, the data indicated that the highest fertility, as well as the greatest number of heifers in heat within 5 days after implant removal, was obtained in those heifers treated with 12 mg SC-21009 and 5 mg estradiol valerate. In Experiment V, fertility of heifers treated 0, 4, 8 or 16 days postestrus with 12 mg SC-21009 and 5 mg estradiol valerate was compared with untreated control heifers. The percent conception at first service of treated heifers (60.8%) did not differ from that of control heifers (63.6%). This content is only available as a PDF. Author notes 3 The authors would like to thank the following for their help and cooperation: D. A. Grant, D. Avery, H. Schaid and F. Schaffer. Copyright 1975 by American Society of Animal Science. American Society of Animal Science