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Reciprocal Recurrent Selection For 21-Day Litter Weight Of Crossbred Gilts. Ii. Reproductive Performance Of Purebred Females Producing Purebred And Two-Way Cross Litters And Performance Of Purebred And Crossbred Pigs, L. D. Young, I. T. Omtvedt, J. A. Whatley Jr., R. K. Johnson
Reciprocal Recurrent Selection For 21-Day Litter Weight Of Crossbred Gilts. Ii. Reproductive Performance Of Purebred Females Producing Purebred And Two-Way Cross Litters And Performance Of Purebred And Crossbred Pigs, L. D. Young, I. T. Omtvedt, J. A. Whatley Jr., R. K. Johnson
Department of Animal Science: Faculty Publications
This paper reports estimates of correlated genetic change in reproductive performance of purebred gilts producing two-way cross litters and purebred sows producing purebred litters as well as postweaning performance of two-way cross and purebred pigs produced during reciprocal recurrent selection (RRS) between Line 8 (Duroc) and Line 9 (Beltsville No. 1) for 21-d litter weight production of crossbred gilts. A randomly mated control line developed from a crossbred foundation was maintained to monitor environmental change. Data were adjusted for age of dam, inbreeding of dam, inbreeding of litter (or pig) and linear and quadratic effects of day born within season. …
Reciprocal Recurrent Selection For 21-Day Litter Weight Of Crossbred Gilts. I. Selection Applied And Genetic Change In Reproduction Of Crossbred Gilts, L. D. Young, I. T. Omtvedt, J. A. Whatley Jr., R. K. Johnson
Reciprocal Recurrent Selection For 21-Day Litter Weight Of Crossbred Gilts. I. Selection Applied And Genetic Change In Reproduction Of Crossbred Gilts, L. D. Young, I. T. Omtvedt, J. A. Whatley Jr., R. K. Johnson
Department of Animal Science: Faculty Publications
Six cycles of reciprocal recurrent selection (RRS) between Line 8 (Duroc) and Line 9 (Beltsville No. 1) were completed at the Fort Reno Livestock Research Center, E1 Reno, Oklahoma. A randomly mated control line was maintained. Each cycle of selection required three seasons. Selection of purebred pigs (born in the second season) was based on the mean 21-d litter weight of their maternal and paternal half-sib crossbred gilts that were born in the first season and farrowed in the third season (XB21DLWT). On the average, 5.8 maternal and paternal half-sib gilts contributed to the mean XB21DLWT for each purebred individual. …
Genetic And Phenotypic Parameters Estimated From Nebraska Speci Fic-Pathogen-Free Swine Field Records, P. J. David, R. K. Johnson, T. E. Socha
Genetic And Phenotypic Parameters Estimated From Nebraska Speci Fic-Pathogen-Free Swine Field Records, P. J. David, R. K. Johnson, T. E. Socha
Department of Animal Science: Faculty Publications
Records collected during 1971 through 1979 from 101,606 hogs raised in 18 Nebraska Specific Pathogen Free herds were analyzed. Traits considered were backfat at 100 kg (BF), weight at 140 d of age (WT) and, in some analyses, number of live pigs/litter at birth (NBA). The phenotypic correlation of BF and WT, averaged across herds, was -.07. The correlations between BF and NBA and between WT and NBA were .04 and -.05, respectively. Average phenotypic standard deviations for BF, WT and NBA were 2.6 mm, 8.8 kg and 2.0 pigs. Estimates of the heritability of BF and WT were lower …
Simulation Of Breed And Crossbreeding Effects On Costs Of Pork Production, G. L. Bennett, W. M. Tess, G. E. Dickerson, R. K. Johnson
Simulation Of Breed And Crossbreeding Effects On Costs Of Pork Production, G. L. Bennett, W. M. Tess, G. E. Dickerson, R. K. Johnson
Department of Animal Science: Faculty Publications
A bio-economic model of swine production was used to simulate expected performance effects of breeds in alternative breeding systems on total costs/100 kg of live weight (EWW) or/l00 kg lean (ELW) for marketing at 100 kg live weight and on costs/100 kg lean for marketing at mean 185-d weight (ELA). Effects of heterosis and of six U.S. breeds were simulated for integrated industry purebred (P), two-breed specific (2S), backcross (2B) and rotation cross (2R), and three-breed specific (3S) and rotation cross (3R) breeding systems. Traits considered were age at puberty (-PUB), conception rate (CR), litter size born alive (NBA), preweaning …
Simulation Of Heterosis Effects On Costs Of Pork Production, G. L. Bennett, M. W. Tess, G. E. Dickerson, R. K. Johnson
Simulation Of Heterosis Effects On Costs Of Pork Production, G. L. Bennett, M. W. Tess, G. E. Dickerson, R. K. Johnson
Department of Animal Science: Faculty Publications
Individual plus maternal heterotic effects on swine production were simulated with a bioeconomic model by changing performance levels of eight traits: -8 d in age at puberty, +3% in conception rate, +.94 in pigs born/litter, +.035 kg in pig birth weight, +2.05 Mcal•sow-1•d -1 in maximum milk output, +8% in preweaning survival, +10.8% in protein growth rate and +17.3% in fat growth rate. Associated heterosis simulated for other traits, such as weaning weights and postweaning gain/feed, was similar to experimental results. Effects of heterosis on biological (feed Mcal/kg) and economic ($/kg) costs were evaluated by simulating two- and …
Index Selection And Feed Intake Restriction In Swine. I. Effect On Rate And Composition Of Growth, Erik R. Cleveland, R. K. Johnson, R. W. Mandigo
Index Selection And Feed Intake Restriction In Swine. I. Effect On Rate And Composition Of Growth, Erik R. Cleveland, R. K. Johnson, R. W. Mandigo
Department of Animal Science: Faculty Publications
The objectives of this experiment were to determine the effects of index selection for increased average daily gain and decreased backfat, and the effects of restriction of daily feed intake, on rate and composition of growth in swine. A total of 53 barrows from select and control lines were randomly assigned to three feeding levels at 83 d of age, and 33 littermate barrows were slaughtered to establish initial body composition. The trial was approximately 105 d and the feeding levels were twice daily to appetite (AP), once daily feeding of 91% of appetite (AP9l) and once daily feeding of …
Index Selection And Feed Intake Restriction In Swine. Ii. Effect On Energy Utilization, Erik R. Cleveland, R. K. Johnson, R. W. Mandigo, E. R. Peo Jr.
Index Selection And Feed Intake Restriction In Swine. Ii. Effect On Energy Utilization, Erik R. Cleveland, R. K. Johnson, R. W. Mandigo, E. R. Peo Jr.
Department of Animal Science: Faculty Publications
Fifty-three index select and control line barrows were randomly assigned to three feeding levels at 83 d of age. They were slaughtered at approximately 188 d of age to determine the effects of index selection (for increased average daily gain and decreased backfat) and level of feed intake on energy utilization. During the trial, the feed intake levels were twice daily to appetite (AP), once daily feeding of 91% of appetite (AP91) or once daily feeding of 82% of appetite (AP82) intake. The metabolizable energy intake required per kilogram of edible lean deposited (Mcal/kg) was reduced (P<.05) by restricting intake and was lower (P<.01) for index than for control barrows [index: 25.6 (AP), 23.3 (AP91) and 25.3 (AP82) vs control: 31.1 (AP), 27.5 (AP91) and 28.1 (AP82)]. However, intake restriction and index selection increased (P<.05) the energy lost per unit of retained energy (index: 1.33, 1.45 and 1.53 vs control: 1.24, 1.29 and 1.34). The index line had a higher (P<.05) maintenance requirement than the control line when expressed unit of weight (kg.75)-1 …
"Dried Fat" For Growing-Finishing Swine, K. E. Keaschall, B. D. Moser, E. R. Peo, Jr., A. J. Lewis, T. D. Crenshaw, Win Butler
"Dried Fat" For Growing-Finishing Swine, K. E. Keaschall, B. D. Moser, E. R. Peo, Jr., A. J. Lewis, T. D. Crenshaw, Win Butler
Department of Animal Science: Faculty Publications
Three trials were conducted to determine the effect of "dried fat" (fats absorbed on carriers) in diets for growing-finishing swine. In trial I pigs receiving diets containing 5% added fat gained faster (.74 vs .71 kg/d), consumed less feed (1.87 vs 2.43 kg/d) and had a better feed efficiency (2.52 vs 2.88) than pigs fed diets without added fat (all P<.01). Pigs given the "dried fat" treatments gained faster (P<.01) and more efficiency (P<.01) than pigs fed the nonfat carrier counterpart. "Dried fats" containing whey plus fat and wheat bran plus fat produced similar performance to that observed with pigs fed a conventional tallow diet.