Journal of Animal Science

Lamberson, W., R.;Blair, R., M.;Rohde Parfet, K., A.;Day, B., N.;Johnson, R., K.

doi: 10.2527/jas1988.663595xpmid: 3378919

Abstract Records on age at puberty from 1,555 gilts and total number of pigs born in litters of 1,187 gilts from the Nebraska gene pool population were used to evaluate the effects of uterine environment on subsequent reproductive performance. Independent variables were line, year, line × year, proportion of males in the birth litter (sex ratio), number born in the birth litter (fraternity size) and sex ratio × fraternity size. Sex ratio, fraternity size and their interaction influenced age at puberty (P < .01) but not number born (P > .2). Partial regression coefficients indicated that age at puberty tended to decrease as sex ratio increased, particularly in small litters. Although the regression coefficients were relatively large, sex ratio, fraternity size and their interaction accounted for only 1.3% of the variation in age at puberty within line × year subclass. These results offer little encouragement for the use of sex ratio as a phenotypic selection criterion for improvement of reproductive performance in gilts. Results suggest that female swine are similar to rodents in response to uterine environmental effects. This content is only available as a PDF. Author notes 2 Dept. of Anim. Sci. 3 Dept. of Anim. Sci. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Beal, W., E.;Chenault, J., R.;Day, M., L.;Corah, L., R.

doi: 10.2527/jas1988.663599xpmid: 3163990

Abstract Beef cows and heifers (n = 263) at three locations that were exhibiting estrous cycles either were fed .5 mg/d melengestrol acetate (MGA) for 7 d and administered prostaglandin F2α (25 mg, i.m.) on the last day of MGA feeding or were untreated. State of the estrous cycle at the beginning of the experiment was determined based on estrous detection and(or) progesterone concentrations in pretreatment blood samples. Estrous was checked twice daily for 30 d posttreatment. Animals were artificially inseminated approximately 12 h after detection of estrus. A synchronized estrus (< 7 d posttreatment) was detected in 72% of the treated animals. More animals in the treated group became pregnant during the first 7 d of breeding, but their conception rate was lower than that of animals in the control group (P < .05). Conception rate (36%) was reduced among treated animals when MGA feeding began late (d 14 to 20) in the estrous cycle. Conversely, the conception rate (66%) of treated animals fed MGA beginning earlier in the cycle was not different from that of control animals (73%; treatment × stage of cycle; P < .05). This content is only available as a PDF. Author notes 2 Dept. of Anim. Sci., Virginia Polytechnic Institute and State University, Blacksburg 24061. 3 Reprod. and Growth Physiol. Unit. The Upjohn Co., Kalamazoo 49001. 4 Dept. Anim. Sci., The Ohio State University, Columbus 43210. 5 Anim. Sci. and Ind. Dept., Kansas State University, Manhattan 66506. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Wagner, J., J.;Lusby, K., S.;Oltjen, J., W.;Rakestraw,, J.;Wettemann, R., P.;Walters, L., E.

doi: 10.2527/jas1988.663603xpmid: 3378920

Abstract Seventy-two mature, nonpregnant, nonlactating Hereford cows (400 kg) were utilized in a comparative slaughter trial to investigate the effects of carcass composition on the metabolizable energy (ME) required for maintenance in winter. Body condition score (CS), live weight (LW) and weight:height ratio (WTHT) were evaluated and compared as estimators of carcass composition in cows. Cows ranged in LW, CS and WTHT from 275 to 595 kg, 2.0 to 8.0 units and 2.29 to 4.62 kg/cm, respectively. Live weight, CS and WTHT predicted total carcass energy (TMCAL, r2 = .81, .85 and .83), carcass fat (FAT, r2 = .78, .82 and .80), carcass protein (PRO, r2 = .71, .74 and .70) and carcass water (WAT, r2 = .78, .71 and .77) with similar accuracy. When composition was expressed on a per unit weight basis, CS was superior to LW and WTHT as predictors of TMCAL/hot carcass weight, TMCAL/LW and FAT/hot carcass weight (r2 = .82, .60 and .64; .83, .58 and .62; and .82, .64 and .68, respectively). Forty-seven cows were individually fed a complete diet (2.50 Mcal ME/dry matter) in drylot for 114 d in yr 1 and 115 d in yr 2. Daily feed intakes were adjusted each week to maintain constant LW throughout the winter. Data were analyzed by fitting the model: ME intake = k−1 (carcass energy change) + f(CS)LW·75, where k = efficiency of ME use for carcass energy change and f(CS) = function of CS. Year as a class variable and the expression .1028 + .0234(CS) − .0025(CS)2 accounted for 41% of the variation in Mcal ME for maintenance/LW·75. Condition score was more closely related to carcass composition in mature cows than was LW or WTHT and cows in either a thin (CS = 3) condition or a fat (CS = 7) condition required less (4.4% and 8.9%) Mcal ME/LW·75 for maintenance than cows in moderate (CS = 5) condition. This content is only available as a PDF. Author notes 2 Dept. of Anim. Sci. 3 Present address: Dept. of Anim. and Range Sci., South Dakota State Univ., Brookings. 4 Present address: XIT Feeders, Dalhart, TX. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Neville, W., E.;Richardson, K., L.;Utley, P., R.

doi: 10.2527/jas1988.663613xpmid: N/A

Abstract Reproductive performances were compared of bulls exposed to 40 vs 50 cows/bull in single-sire units during a 90-d to 95-d breeding period on pasture. Bulls were Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG). Bulls were not subjected to a breeding soundness examination (BSE) for yr 1; however, all bulls passed the BSE for yr 2 and 3. Cows were A, PH and SG straightbreds and crossbreds of these breeds. Each year cows were allotted at random within breed composition, age of dam and calving date to breeding groups. There were 25 of the 40-cow and 25 of the 50-cow groups. Nine, eight and eight A, PH and SG bulls, respectively, were used in each group size. Reproductive performances of bulls were evaluated in terms of calving rate (CR) of cows and number of days (NOD) from start of breeding until calf birth. Results indicated similar CR and NOD for the 40-cow and 50-cow groups and for the three sire breeds. However, there was a significant year × sire breed interaction for CR. Significant differences among sires within sire breed occurred for CR, but not for NOD. Both cow groups had bulls with high and with low reproductive performance. This content is only available as a PDF. Author notes 1 The authors appreciate the cooperation of personnel at the Rogers Correctional Institution, Reidsville (a part of the Georgia Dept. of Corrections), which permitted this research. Also the authors gratefully acknowledge the assistance of B. G. Mullinix, Jr., for conducting the statistical analyses. 3 Dept. of Anim. Sci., Coastal Plain Sta. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Wilson, D., E.;Willham, R., L.

doi: 10.2527/jas1988.663618xpmid: N/A

Abstract A procedure was tested that would enable beef cattle breed associations to compute interim expected progeny differences (EPD) for direct growth traits of young animals not included in the most recent national cattle evaluation (NCE). The procedure estimated contemporary group (CG) fixed effects of young animals just measured by adjusting records of young animals for the predicted breeding values of their parents obtained from the last NCE, if available, and then by obtaining a weighted average of adjusted records. The weighting was governed by whether or not the EPD of the parents were available from the last NCE. The difference between the performance record of an animal and the CG estimate was used to obtain a prediction of effect due to Mendelian sampling for that animal. Interim EPD were computed as half the sum of the EPD of sire and dam for each trait of interest plus half the effect due to Mendelian sampling of the animal. Interim EPD were computed sequentially by CG, allowing records to be processed by the associations upon receipt from breeders. To test the procedure, rank correlations were computed between interim EPD of young animals and their EPD from the NCE of 1986. Rank correlations between interim EPD and EPD from the NCE of 1986 for young animals with EPD available from the NCE of 1985 for both parents were .93, .93 and .96 for birth, direct weaning and yearling weights, respectively. For young animals with only the EPD of sire available from the NCE of 1985, rank correlations between interim and actual EPD were .83, .84 and .82 for birth, direct weaning and yearling weights, respectively. This content is only available as a PDF. Author notes 2 Authors gratefully acknowledge the help of American Angus Assoc. and Larry Benyshek and Del Little, Univ. of Georgia, in assembling data used in this project. Copyright 1988 by American Society of Animal Science American Society of Animal Science

, de Rose, E. P.;Wilton, J., W.;Schaeffer, L., R.

doi: 10.2527/jas1988.663626xpmid: N/A

Abstract Canadian test station data were used to estimate variance components and heritabilities for average daily gain on test, end-of-test height at hooks, s.c. fat thickness and scrotal circumference for Aberdeen Angus, Charolais, Hereford, Limousin, Shorthorn and Simmental bulls. Preweaning average daily gain records were obtained for tested bulls from the Federal-Provincial Herd Record of Performance program. The sire model for the estimation of variance components for traits measured at central test stations contained contemporary group as a fixed effect, regression on end-of-test age and a random sire effect. The model for preweaning average daily gain contained herd-year as a fixed effect, linear and quadratic regressions on weaning age and a random sire effect. Variance components were estimated separately for each breed using maximum likelihood procedures. Height, fat thickness and scrotal circumference were analyzed with single-trait models, whereas preweaning and test-station average daily gain were analyzed with a two-trait model. Heritabilities, averaged across breeds, were estimated as .25, .44, .85, .49 and .53 for preweaning average daily gain, test-station average daily gain, height, fat thickness and scrotal circumference, respectively. Differences were found between breeds. Average estimates of the phenotypic, genetic and environmental correlations between preweaning and test-station average daily gain were .03, .49 and −.19, respectively. This content is only available as a PDF. Author notes 1 The authors acknowledge the financial assistance of the Red Meat Program of the Ontario Ministry of Agric. and Food, and of the Natural Sci. and Eng. Res. Council of Canada. G. Crow and M. Donetz are acknowledged for their contribution of the Manitoba data. 2 Dept. of Anim. and Poultry Sci. Copyright 1988 by American Society of Animal Science American Society of Animal Science

, de Rose, E. P.;Wilton, J., W.;Schaeffer, L., R.

doi: 10.2527/jas1988.663635xpmid: N/A

Abstract Station-tested beef bulls were evaluated for postweaning average daily gain using a single-trait best linear unbiased prediction (BLUP) animal model and a two-trait BLUP animal model incorporating information on the correlated trait of average daily gain to weaning. The model for average daily gain to weaning contained breed and herd-year as fixed effects, linear and quadratic covariates of age at weaning and a random animal effect. The model for test-station average daily gain contained breed and test group as fixed effects and a random animal effect. Records on both growth traits were available on 5,082 Aberdeen Angus, Charolais, Hereford, Limousin, Shorthorn and Simmental bulls tested in Canada. Preweaning average daily gain records were available on 14,939 more untested bull calves from herd-years represented by at least one tested bull. Paternal half-sib information was incorporated into both the single and two-trait analyses. The two-trait model accounted for the selection of bulls entering test stations on the basis of phenotypic performance to weaning and for pretest environmental carry-over and the resulting effects on performance in the test station. Estimated breeding values from the theoretically best model, a two-trait BLUP animal model with maternal grandsire (MGS) information, were correlated with evaluations from other models. Correlations were .84, .87, .88 and .92, respectively, between the best model and in index based on a simple contemporary comparison, single-trait BLUP, single-trait BLUP with MGS information, and two-trait BLUP (without MGS) models. The two-trait MGS model and an index based on a simple contemporary comparison, single-trait BLUP, single-trait BLUP with MGS information, and two-trait BLUP (without MGS) models. The two-trait MGS of the effects of preselection and environmental carry-over. Significant reranking of bulls can be expected with use of the two-trait evaluation. The application of such an approach in existing testing programs is recommended. This content is only available as a PDF. Author notes 1 The authors acknowledge the financial assistance of the Red Meat Program of the Ontario Ministry of Agric. and Food, and of the Natural Sci. and Eng. Res. Council of Canada. G. Crow and M. Donetz are acknowledged for their contribution of the Manitoba data. 2 Dept. of Anim. and Poultry Sci. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Tanida,, H.;Hohenboken, W., D.;DeNise, S., K.

doi: 10.2527/jas1988.663640xpmid: 3378921

Abstract Thirty years and 23 yr of life history data from a Hereford herd in Arizona and an Angus herd in Wyoming, respectively, were analyzed. Longevity averaged 4.21 ± .06 for years from first calving to disposal (FST), 7.40 ± .06 for years from birth to disposal (AGE) and 3.46 ± .06 for lifetime number of calves weaned (NUM) in Herefords and 4.49 ± .13 (FST), 6.68 ± .12 (AGE) and 3.66 ± .11 (NUM) in Angus. In the Hereford herd, heritability estimates for traits measuring longevity, estimated from daughter-dam regression and paternal half-sib analyses, ranged from .16 to .26. In the Angus herd, heritability estimates from daughter-dam regression ranged from .03 to .05. In the Hereford herd, genetic correlations of birth weight and weaning weight with longevity, from daughter-dam regression, were negative and generally of low magnitude, whereas genetic correlations between weaning condition score and longevity were positive and moderate. Analogous estimates from paternal half-sib analyses all were positive and moderate to high. Phenotypic correlations between early life traits and longevity traits in Herefords all were near zero. In the Angus herd, curves for age-specific survivorship and age-specific survival rate varied markedly among sires. This study suggested the existence of moderate genetic variation for longevity traits in beef cattle. None of the traits expressed early in life that were examined would, however, be reliable predictors of genetic or phenotypic merit for longevity. This content is only available as a PDF. Author notes 2 Dept. of Anim. Sci., Oregon State Univ. 3 Current Address: Azabu Univ., 1-17-71, Fuchinobe, Sagamihara-shi, Kanagawa-ken, 229 Japan. 4 Current address: Dept. of Anim. Sci., Virginia Polytechnic Institute and State Univ., Blacksburg VA 24061. 5 Dept. of Anim. Sci., Univ. of Arizona. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Cantet,, R.J.C.;Kress, D., D.;Anderson, D., C.;Doornbos, D., E.;Burfening, P., J.;Blackwell, R., L.

doi: 10.2527/jas1988.663648xpmid: 3378922

Abstract Birth weights (BW) and weaning weights (WW) of 4,423 non-creep-fed Hereford calves were used to estimate direct and maternal sources of variation and maternal phenotypic effects (fm). Seventeen different (co)variances among relatives were estimated through Henderson's Method III and restricted estimated maximum likelihood procedures. Direct and maternal (co)variances and fm were evaluated by multiple regression procedures. Estimates of h2 for BW and WW were .28 and .28 respectively, by the paternal half-sib procedure and .45 and .88, respectively, based on full-sibs. Repeatability estimates were .21 for BW and .30 for WW. Heritabilities based on regression of offspring on dam and offspring on sire were .45 and .21 for BW and .28 and .06 for WW, respectively. Negative correlations were found between solutions for additive genetic direct and additive maternal effects (rG). Estimates of rG ranged from −.86 to −1.05 for BW and from −.57 to −.79 for WW. Estimates of heritability for direct effects (h2O), for maternal effects (h2m) and for total additive genetic effects (h2T) were .16 to .27, .18 to .63 and −.02 to .05 for BW and .26 to .32, .27 to .67 and .10 to .20 for WW. Dominance affected both direct and maternal effects for BW and WW. Values of −.15 (BW) and −.25 (WW) were found for fm (path coefficient between the maternal phenotypes of dam and daughter). These results indicated that selection response would be decreased due to the negative genetic correlation between direct and maternal effects. This content is only available as a PDF. Author notes 2 Departamento de Zootecnia, Fac. de Agronomia, Univ. de Buenos Aires, Argentina. Present Address: Dept. of Anim. Sci., Univ. of Il, Urbana. 3 Dept. of Anim. and Range Sci., Montana State Univ., Bozeman 59717. 4 Direct reprint requests to this author. 5 Northern Agric. Res. Center, Star Route 36, Box 43, Havre, MT 59501. 6 Authors gratefully acknowledge the helpful suggestions of Daniel Gianola. Copyright 1988 by American Society of Animal Science American Society of Animal Science

Petrie, C., L.;Gonyou, H., W.

doi: 10.2527/jas1988.663661xpmid: 3378923

Abstract Auditory, chemical and visual stimuli were used in a factorial trial in an attempt to stimulate feeding in newly weaned piglets. Ninety-six crossbred piglets weaned at 28 d of age were assigned to groups containing four littermates. Each group was placed in a 1.2-m × 1.2-m pen in an isolated room for 48 h. Pens were equipped with nipple waterers and trough-type feeders. The auditory stimulus was piglet and sow nursing vocalizations. A visual stimulus was provided by a lamp that illuminated the feeding area. Auditory and visual stimuli were presented for 5 min once an hour for 48 h. The chemical stimulus consisted of 60 ml of evaporated milk sprayed over the surface of the feed once every 12 h. Water was used in place of milk in control treatments. Piglets were videotaped for 48 h. Frequency and duration of feeding, drinking and lying were recorded for two piglets out of each pen. Auditory stimuli increased (P < .05) the number of drinking bouts per day from 16.3 to 19.2 and the number of drinking bouts associated with stimulus presentation from 6.2 to 8.0 There also was an auditory × day interaction effect on total time spent feeding. On d 2 postweaning piglets in the auditory treatment group spent more (P < .05) time feeding than did those without auditory stimulation (127.1 vs 104.2 min, respectively). The relatively simple visual and chemical stimuli tested had no significant effects on ingestive behavior. On d 2 postweaning, total time spent feeding increased (P < .001) to 115.7 min from 55.5 min on the 1st d. In addition, the maximum time between consecutive feedings decreased (P < .01) from 381 min on d 1 to 303 min on d 2. This content is only available as a PDF. Author notes 1 Dept. of Anim. Sci. Copyright 1988 by American Society of Animal Science American Society of Animal Science