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Life Sciences

University of Nebraska - Lincoln

2004

Selection

Articles 1 - 8 of 8

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Follicular Development And Maturation In Gilts Selected For An Index Of High Ovulation Rate And High Prenatal Survival, H.-W. Yen, J. J. Ford, D. R. Zimmerman, R. K. Johnson Nov 2004

Follicular Development And Maturation In Gilts Selected For An Index Of High Ovulation Rate And High Prenatal Survival, H.-W. Yen, J. J. Ford, D. R. Zimmerman, R. K. Johnson

Department of Animal Science: Faculty Publications

Seventy-one 10th-generation gilts from White Line-1 (WL-1 = randomly selected control line) and White Line-2 (WL-2 = selected for an index of ovulation rate and prenatal survival rate) were used to compare the pattern of follicular development and atresia during the follicular phase of the estrous cycle. Gilts were treated with PGF on d 13 of the estrous cycle (d 0 of induced follicular development) to induce luteolysis and assigned randomly within line and sire for ovary recovery on d 0, 2, 3, 4, 5, and the day after estrus. Ovaries were evaluated for numbers of corpora albicantia and …


Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr And Human Microarrays: I. Ovarian Follicles, C. D. Gladney, G. R. Bertani, R. K. Johnson, Daniel Pomp Oct 2004

Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr And Human Microarrays: I. Ovarian Follicles, C. D. Gladney, G. R. Bertani, R. K. Johnson, Daniel Pomp

Department of Animal Science: Faculty Publications

Differential display PCR (ddPCR) and complementary DNA microarray analyses were used to evaluate gene expression differences in porcine ovarian follicles between a line of pigs selected for an index of ovulation rate and embryo survival (Line I) and its randomly selected control line (Line C). Follicles (4.0 to 7.0 mm) were dissected from ovaries of multiparous sows (n = 27) at either 2 or 4 d following PGF2α analog injection on d 12 to 14 of the estrous cycle. Using ddPCR, differentially expressed bands (n = 282) were excised from gels and 107 were sequenced, yielding 84 unique porcine follicle …


Responses To 19 Generations Of Litter Size Selection In The Ne Index Line. Ii. Growth And Carcass Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, J. W. Holl, R. K. Johnson Jun 2004

Responses To 19 Generations Of Litter Size Selection In The Ne Index Line. Ii. Growth And Carcass Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, J. W. Holl, R. K. Johnson

Department of Animal Science: Faculty Publications

Our objective was to estimate responses in growth and carcass traits in the NE Index line (I) that was selected for 19 generations for increased litter size. Differences between Line I and the randomly selected control line (C) were estimated in pure line litters and in F1 and three-way cross litters produced by mating I and C females with males of unrelated lines. Contrasts of means were used to estimate the genetic difference between I and C and interactions of line differences with mating type. In Exp 1, 694 gilts that were retained for breeding, including 538 I and …


Genetic Parameters For Six Measures Of Length Of Productive Life And Three Measures Of Lifetime Production By 6 Yr After First Calving For Hereford Cows, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck Jun 2004

Genetic Parameters For Six Measures Of Length Of Productive Life And Three Measures Of Lifetime Production By 6 Yr After First Calving For Hereford Cows, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Genetic parameters for length of productive life given the opportunity (LPL|O), measured as days between first calving and disposal conditioned on one of six opportunity groups, L1 through L6 (e.g., L2 is length of productive life in days given the opportunity to live 2 yr after first calving), and lifetime production (LP), measured as the number of calves born (NB), number of calves weaned (NW), and cumulative weaning weight (CW) by 6 yr after first calving, were estimated using records of 1,886 Hereford cows from a selection experiment with three selected lines and a control line. Weaning weights were adjusted …


Number Of Calves Born, Number Of Calves Weaned, And Cumulative Weaning Weight As Measures Of Lifetime Production For Hereford Cows, G. E. Martinez, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck Jun 2004

Number Of Calves Born, Number Of Calves Weaned, And Cumulative Weaning Weight As Measures Of Lifetime Production For Hereford Cows, G. E. Martinez, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Genetic parameters for lifetime production for cows with the opportunity to produce from 2 through 7 yr of age, as measured by the number of calves born (NB2, …, NB7), the number of calves weaned (NW2, …, NW7), and cumulative weaning weight (CW2,…, CW7), were estimated using data from 3,064 Hereford cows from a selection experiment with a control line (CTL) and three lines selected for weaning weight (WWL), yearling weight (YWL), and an index of yearling weight and muscle score (IXL). Weaning weights were adjusted to 200 d of age and for sex and age of dam. Estimates of …


Responses To 19 Generations Of Litter Size Selection In The Nebraska Index Line. I. Reproductive Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, Rodger K. Johnson Mar 2004

Responses To 19 Generations Of Litter Size Selection In The Nebraska Index Line. I. Reproductive Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, Rodger K. Johnson

Department of Animal Science: Faculty Publications

Our objective was to estimate responses in reproductive traits in the Nebraska Index line (I) after 19 generations of selection for increased litter size. Responses were estimated in dams producing pure line, F1, and three-way cross litters. A total of 850 litters were produced over six year-seasons, including 224 pure line litters, 393 F1 litters produced from I and C females mated with DanbredNALandrace (L) or Duroc- Hampshire (T) boars, and 233 litters by F1 L x I and L x C females mated with T boars. Contrasts of means were used to estimate the genetic …


Genetic Response To Selection For Weaning Weight Or Yearling Weight Or Yearling Weight And Muscle Score In Hereford Cattle: Efficiency Of Gain, Growth, And Carcass Characteristics, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck Feb 2004

Genetic Response To Selection For Weaning Weight Or Yearling Weight Or Yearling Weight And Muscle Score In Hereford Cattle: Efficiency Of Gain, Growth, And Carcass Characteristics, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

An experiment involving crosses among selection and control lines was conducted to partition direct and maternal additive genetic response to 20 yr of selection for 1) weaning weight, 2) yearling weight, and 3) index of yearling weight and muscle score. Selection response was evaluated for efficiency of gain, growth from birth through market weight, and carcass characteristics. Heritability and genetic correlations among traits were estimated using animal model analyses. Over a time-constant interval, selected lines were heavier, gained more weight, consumed more ME, and had more gain/ME than the control. Over a weight-constant interval, selected lines required fewer days, consumed …


Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr And Human Microarrays: I. Ovarian Follicles, C. D. Gladney, G. R. Bertani, R. K. Johnson, Daniel Pomp Jan 2004

Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr And Human Microarrays: I. Ovarian Follicles, C. D. Gladney, G. R. Bertani, R. K. Johnson, Daniel Pomp

Department of Animal Science: Faculty Publications

Differential display PCR (ddPCR) and complementary DNA microarray analyses were used to evaluate gene expression differences in porcine ovarian follicles between a line of pigs selected for an index of ovulation rate and embryo survival (Line I) and its randomly selected control line (Line C). Follicles (4.0 to 7.0 mm) were dissected from ovaries of multiparous sows (n = 27) at either 2 or 4 d following PGF analog injection on d 12 to 14 of the estrous cycle. Using ddPCR, differentially expressed bands (n = 282) were excised from gels and 107 were sequenced, yielding 84 unique porcine …