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Department of Animal Science: Faculty Publications

Articles 781 - 810 of 1242

Full-Text Articles in Animal Sciences

Genetics Of The Interval From Weaning To Estrus In First-Litter Sows: Correlated Responses, J. Ten Napel, T. H. E. Meuwissen, R. K. Johnson, E. W. Brascamp Oct 1998

Genetics Of The Interval From Weaning To Estrus In First-Litter Sows: Correlated Responses, J. Ten Napel, T. H. E. Meuwissen, R. K. Johnson, E. W. Brascamp

Department of Animal Science: Faculty Publications

The objective of this study was to evaluate relationships between rebreeding performance and growth performance (n = 3,777 gilts) and rebreeding performance and reproductive performance (n = 2,242 sows). Our data were from a selection experiment for shorter intervals from weaning to estrus after the first parity (IWE), involving Dutch Landrace pigs, in which a selection line and a control line without selection were maintained for eight generations. Relationships were evaluated before and after transforming IWE to normal interval (NI; IWE &#; 7 d), prolonged interval (PI; IWE > 7 d), and incidence of a prolonged interval (INC). Heritabilities of NI, …

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Genetic And Phenotypic Parameters For Carcass Traits Of American Shorthorn Beef Cattle, F. Pariacote, R. E. Hunsley, L. Dale Van Vleck Jun 1998

Genetic And Phenotypic Parameters For Carcass Traits Of American Shorthorn Beef Cattle, F. Pariacote, R. E. Hunsley, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Carcass measurements were taken on 1,292 steers and collected by the American Shorthorn Association. The sires were purebred or appendix-registered Shorthorn. Because all dams were not Shorthorn, genetic fractions of breeds of origin were determined for each dam. Measurements for hot carcass weight; dressing percentage; fat thickness; ribeye area; kidney, pelvic, and heart fat (KPH); marbling; and yield grade were analyzed jointly with a multivariate REML algorithm to estimate heritabilities of and genetic and phenotypic correlations among the traits. The sire model chosen as best fit of the data included fixed effects of herd of origin (377 classes), slaughter group …

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Parameter Estimates For Direct, Maternal, And Grandmaternal Genetic Effects For Birth Weight And Weaning Weight In Hereford Cattle, J. Dodenhoff, L. Dale Van Vleck, Stephen D. Kachman, R. M. Koch Jun 1998

Parameter Estimates For Direct, Maternal, And Grandmaternal Genetic Effects For Birth Weight And Weaning Weight In Hereford Cattle, J. Dodenhoff, L. Dale Van Vleck, Stephen D. Kachman, R. M. Koch

Department of Animal Science: Faculty Publications

Birth and weaning weights adjusted for age of dam from four lines of Hereford cattle were analyzed to determine the relationships among grandmaternal, maternal, and direct genetic effects. Three lines were selected for 1) weaning weight (WWL), 2) yearling weight (YWL), and 3) an index of yearling weight and muscle score (IXL). The fourth line was an unselected control line (CTL). Numbers of observations ranged from 1,699 (CTL) to 2,811 (WWL), and number of animals in the pedigree file ranged from 2,266 to 3,192. Two animal models were used to obtain estimates by REML using an average information method. Model …

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Genetic Parameters For Sex-Specific Traits In Beef Cattle, R. K. Splan, Larry V. Cundiff, L. Dale Van Vleck May 1998

Genetic Parameters For Sex-Specific Traits In Beef Cattle, R. K. Splan, Larry V. Cundiff, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Data from 3,593 beef heifers and 4,079 of their steer paternal half-sibs were used to estimate genetic parameters of and among female growth and reproductive traits and male carcass traits. Estimates of heritability for adjusted 205-d weight, adjusted 365-d weight, age at puberty, calving rate, and calving difficulty measured on females were .16, .38, .47, .19, and .18, respectively; estimates for calving rate and calving difficulty were expressed on a normal scale. Estimates of heritability for hot carcass weight; retail product percentage; fat percentage; bone percentage; rib eye area; kidney, pelvic, and heart fat percentage; adjusted fat thickness; marbling score; …

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Estimation Of Relative Economic Value For Herd Life Of Dairy Cattle From Profile Equations, S. Jagannatha, Jeffrey F. Keown, L. Dale Van Vleck Feb 1998

Estimation Of Relative Economic Value For Herd Life Of Dairy Cattle From Profile Equations, S. Jagannatha, Jeffrey F. Keown, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Lifetime records of 122,679 cows from 7557 herds, obtained from Mid States Dairy Records Processing Center (Ames, IA), were used to determine net income and net income for the planning horizon. With a planning horizon of five lactations for each cow, the estimated profit from the replacements was credited to each cow not surviving until fifth calving. Net income was defined as lifetime income minus costs. Net income for the planning horizon was defined as net income plus profit from replacements within the planning horizon. Income was from the sale of milk, calves, and culled cows. Costs were included for …

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Developmental And Hormonal Regulation Of Transforming Growth Factor- Β1 (Tgfβ1), -2, And -3 Gene Expression In Isolated Prostatic Epithelial And Stromal Cells: Epidermal Growth Factor And Tgfβ Interactions, Naoki Itoh, Urvashi Patel, Andrea S. Cupp, Michael K. Skinner Feb 1998

Developmental And Hormonal Regulation Of Transforming Growth Factor- Β1 (Tgfβ1), -2, And -3 Gene Expression In Isolated Prostatic Epithelial And Stromal Cells: Epidermal Growth Factor And Tgfβ Interactions, Naoki Itoh, Urvashi Patel, Andrea S. Cupp, Michael K. Skinner

Department of Animal Science: Faculty Publications

Growth factors are postulated to mediate stromal-epithelial interactions in the prostate to maintain normal tissue physiology. Transforming growth factor-β (TGFβ) has been shown to influence the prostate and probably mediate stromal-epithelial interactions. TGFβ1 messenger RNA (mRNA) expression is stimulated after castration and can be suppressed by in vivo treatment with androgens. The hypothesis tested is that TGFβ is regulated not only by androgen, but also by a network of locally produced growth factors that influence prostatic growth and differentiation. Epithelial and stromal cells from 20-day-old rat ventral prostate were isolated and used to test this hypothesis. The expression of mRNA …

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Sex Effects On Breed Of Sire Differences For Birth, Weaning, And Yearling Weights, L. Dale Van Vleck, Larry V. Cundiff Jan 1998

Sex Effects On Breed Of Sire Differences For Birth, Weaning, And Yearling Weights, L. Dale Van Vleck, Larry V. Cundiff

Department of Animal Science: Faculty Publications

Weights of males and females can be considered to be correlated traits with different averages and variances. This study attempted to determine whether defining traits as expressed in males or in females would change estimates of breed of sire differences needed to calculate across-breed factors for adjustment of within-breed EPD to across-breed EPD. Records from the US Meat Animal Research Center of progeny of Hereford, Angus, and MARC III composite dams mated to 12 sire breeds that had been used to calculate breed of sire adjustments in 1996 were used. Breeds of sire were Hereford, Angus, Shorthorn, Brahman, Simmental, Limousin, …

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Bayesian Analysis Of Twinning And Ovulation Rates Using A Multiple-Trait Threshold Model And Gibbs Sampling, C. P. Van Tassell, L. Dale Van Vleck, K. E. Gregory Jan 1998

Bayesian Analysis Of Twinning And Ovulation Rates Using A Multiple-Trait Threshold Model And Gibbs Sampling, C. P. Van Tassell, L. Dale Van Vleck, K. E. Gregory

Department of Animal Science: Faculty Publications

The Multiple-Trait Gibbs Sampler for Animal Models programs were extended to allow analysis of ordered categorical data using a Bayesian threshold model. The algorithm is based on data augmentation, where a value on the unobserved underlying normally distributed variable (liability) is generated in each round of iteration for each categorical observation. The programs allow analysis of several continuous and ordered categorical traits. Categorical traits can have any number of response levels. Models can be different for each trait. The programs were used to analyze twinning and ovulation rates from a herd of cattle selected for twinning rate at the U.S. …

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Consequences Of Differing Wool Growth Rates On Staple Strength Of Merino Wethers With Divergent Staple Strengths, A. C. Schlink, G. Mata, R. M. Lewis Jan 1998

Consequences Of Differing Wool Growth Rates On Staple Strength Of Merino Wethers With Divergent Staple Strengths, A. C. Schlink, G. Mata, R. M. Lewis

Department of Animal Science: Faculty Publications

An experiment was conducted to determine the effects of dietary protein intake after a period of weight loss on the wool components of staple strength for sheep with a history of low or high staple strength (18.0 vs 34 Nlktex). After being fed to lose 15% of their liveweight over 10 weeks, sheep within each staple strength group were assigned in equal numbers to either a low or high protein diet designed to re-gain initialliveweight in 8 weeks. Liveweight, feed intakes and the growth, fibre diameter and fibre length characteristics of wool were measured at regular intervals. After the weight …

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Comparison Of Sire Breed Solutions For Growth Traits Adjusted By Mean Expected Progeny Differences To A 1993 Base, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff, D. S. Buchmann, D. M. Marshall Jan 1998

Comparison Of Sire Breed Solutions For Growth Traits Adjusted By Mean Expected Progeny Differences To A 1993 Base, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff, D. S. Buchmann, D. M. Marshall

Department of Animal Science: Faculty Publications

Records on growth traits were obtained from five Midwestern agricultural experiment stations as part of a beef cattle crossbreeding project (NC-196). Records on birth weight (BWT, n =3,490), weaning weight (WWT, n = 3,237), and yearling weight (YWT, n = 1,372) were analyzed within locations and pooled across locations to obtain estimates of breed of sire differences. Solutions for breed of sire differences were adjusted to the common base year of 1993. Then, factors to use with within-breed expected progeny differences (EPD) to obtain a crossbreed EPD were calculated. These factors were compared with factors obtained from similar analyses of …

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Effects Of Inbreeding And Heterozygosity On Preweaning Traits In A Closed Population Of Herefords Under Selection, L. Dale Van Vleck, M. D. Macneil Jan 1998

Effects Of Inbreeding And Heterozygosity On Preweaning Traits In A Closed Population Of Herefords Under Selection, L. Dale Van Vleck, M. D. Macneil

Department of Animal Science: Faculty Publications

Records of five inbred lines at the Livestock and Range Research Laboratory were used to evaluate effects of inbreeding and heterozygosity on preweaning traits. Members of each line were descendants of a single founder Hereford bull. A total of 8,065 records of birth weight and 7,380 records of preweaning daily gain and weaning weight were analyzed by derivative-free REML using a model that included fixed effects of sex, combination of year and month of birth and parity of dam, with covariates for direct and maternal genetic fractions of inheritance from the genetic groups, inbreeding, and heterozygosity fractions. Heterozygosity fractions were …

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Effect Of Energy Source And Escape Protein On Receiving And Finishing Performance And Health Of Calves, R. A. Mccoy, Rick Stock, Terry J. Klopfenstein, D. H. Shain, M. J. Klemesrud Jan 1998

Effect Of Energy Source And Escape Protein On Receiving And Finishing Performance And Health Of Calves, R. A. Mccoy, Rick Stock, Terry J. Klopfenstein, D. H. Shain, M. J. Klemesrud

Department of Animal Science: Faculty Publications

Two receiving and two finishing trials evaluated energy source and escape protein supplementation for calves. In receiving Trial 1, 398 calves (257 ± 24 kg BW) were used in a 2 x 2 factorial arrangement of treatments. Energy sources were dryrolled corn (DRC) and wet corn gluten feed (WCGF); each was fed without or with supplemental escape protein (EP). Calves fed WCGF gained slower ( P < .05) and consumed less DM ( P < .01) than calves fed DRC. Feed efficiency improved ( P < .10) with EP supplementation. In finishing Trial 1, 240 calves (305 ± 21 kg BW) were used. The arrangement of treatments was the same as in receiving Trial 1. Calves fed DRC/WCGF tended ( P = .15) to be more efficient and consumed less DM ( P < .05) than calves fed DRC. In receiving Trial 2, 315 calves (252 ± 23 kg BW) were fed diets similar to those fed in receiving Trial 1. Calves fed WCGF consumed less DM ( P < .01), gained similarly ( P > .15), and were more efficient ( P < .10) than calves fed DRC. In finishing Trial 2, 320 calves (298 ± 23 kg BW) were fed diets containing DRC, DRC/WCGF, high-moisture corn (HMC), HMC/WCGF, and DRC/HMC; each was fed without or with supplemental EP. An energy source ´ protein supplement interaction was detected for gain ( P < .05) and efficiency ( P < .01). Results suggest that WCGF has a NEg greater than DRC in receiving diets and a NEg similar to that of DRC but lower than that of HMC in finishing diets.

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Evaluation Of The Ovine Callipyge Locus: Ii. Genotypic Effects On Growth, Slaughter, And Carcass Traits, B. A. Freking, J. W. Keele, Merlyn K. Nielsen, Kreg A. Leymaster Jan 1998

Evaluation Of The Ovine Callipyge Locus: Ii. Genotypic Effects On Growth, Slaughter, And Carcass Traits, B. A. Freking, J. W. Keele, Merlyn K. Nielsen, Kreg A. Leymaster

Department of Animal Science: Faculty Publications

A resource flock of 362 F2 lambs provided phenotypic and genotypic data to estimate effects of callipyge ( CLPG) genotypes on growth, slaughter, and carcass traits. Lambs were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age to allow comparisons at different end points. Probabilities of CLPG genotypes were calculated at a position 86 cM from the most centromeric marker of chromosome 18. A contrast of CLPG genotypic effects, based on the paternal polar over-dominance model, was used to evaluate callipyge and normal phenotypes. Relationships of traits with slaughter age, carcass weight, or 12th-rib fat …

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Evaluation Of The Ovine Callipyge Locus: I. Relative Chromosomal Position And Gene Action, B. A. Freking, J. W. Keele, C. W. Beattie, S. M. Kappes, T. P.L. Smith, T. S. Sonstegard, Merlyn K. Nielsen, Kreg A. Leymaster Jan 1998

Evaluation Of The Ovine Callipyge Locus: I. Relative Chromosomal Position And Gene Action, B. A. Freking, J. W. Keele, C. W. Beattie, S. M. Kappes, T. P.L. Smith, T. S. Sonstegard, Merlyn K. Nielsen, Kreg A. Leymaster

Department of Animal Science: Faculty Publications

Genotypic and phenotypic data were collected to estimate chromosomal position of the callipyge (CLPG) gene and to test gene action. Nine Dorset rams of extreme muscling phenotype and 114 Romanov ewes composed the grandparent generation of a resource flock of 362 F2 lambs segregating at the CLPG locus. The parent generation consisted of eight F2 sires and 138 F1 dams. The F2 lambs were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age to allow comparisons at different end points. A linkage group of 25 marker loci (mean of 708 informative …

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Effect Of Wet Corn Gluten Feed, Supplemental Protein, And Tallow On Steer Finishing Performance, C. J. Richards, Rick Stock, Terry J. Klopfenstein, D. H. Shain Jan 1998

Effect Of Wet Corn Gluten Feed, Supplemental Protein, And Tallow On Steer Finishing Performance, C. J. Richards, Rick Stock, Terry J. Klopfenstein, D. H. Shain

Department of Animal Science: Faculty Publications

Two trials evaluated the effects of level of wet corn gluten feed (WCGF), type of supplemental protein, and supplemental tallow on steer finishing performance. In Trial 1, WCGF was fed at 0, 25 (two diets), or 50% of the dietary DM replacing dry-rolled corn (DRC), molasses, and a portion of the supplement. The DRC control diet and one 25% WCGF diet were supplemented with a combination of protein sources. The second 25% WCGF diet was supplemented with urea alone. The 50% WCGF diet contained no additional protein supplementation. No differences in DMI (P > .10) were observed. Calves fed 25% WCGF …

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Effect Of Degradable Intake Protein Level On Finishing Cattle Performance And Ruminal Metabolism, D. H. Shain, Rick Stock, Terry J. Klopfenstein, D. W. Herold Jan 1998

Effect Of Degradable Intake Protein Level On Finishing Cattle Performance And Ruminal Metabolism, D. H. Shain, Rick Stock, Terry J. Klopfenstein, D. W. Herold

Department of Animal Science: Faculty Publications

Two finishing trials and a metabolism trial were conducted to evaluate level of supplemental degradable intake (crude) protein (DIP) in finishing diets on cattle performance, carcass characteristics, and ruminal metabolism. Finishing trials were conducted in two consecutive years using 128 crossbred yearling steers (BW = 343 ± 5 kg, Trial 1) and 176 crossbred yearling steers (BW = 375 ± 4 kg, Trial 2) in a randomized complete block design. Steers were fed dry-rolled corn diets containing urea at 0, .88, 1.34, or 1.96% (DM basis). No differences in DMI, daily gain, or feed efficiency were noted among steers receiving …

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Complementary Responses Between Feather Meal And Poultry By-Product Meal With Or Without Ruminally Protected Methionine And Lysine In Growing Calves, M. J. Klemesrud, Terry J. Klopfenstein, Austin Lewis Jan 1998

Complementary Responses Between Feather Meal And Poultry By-Product Meal With Or Without Ruminally Protected Methionine And Lysine In Growing Calves, M. J. Klemesrud, Terry J. Klopfenstein, Austin Lewis

Department of Animal Science: Faculty Publications

We evaluated feather meal (FTH) and poultry by-product meal (PBM) as complementary protein sources for growing calves. In a replicated 84-d growth trial, individually fed steer calves (n = 120; 252 ± 24 kg) were supplemented with urea or with graded levels of soybean meal (SBM), FTH, PBM, or 2/3 FTH:1/3 PBM (CP basis). Protein efficiency, calculated as gain above the urea control vs natural protein intake using the slope-ratio technique, was greater for FTH than for SBM, PBM, and 2/3 FTH:1/3 PBM ( P < .10). Addition of ruminally protected methionine and lysine did not affect protein efficiency ( P > .30) for FTH, PBM, or 2/3 FTH:1/3 PBM. Even though true protein digestibility in the …

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Effect Of Acute Treatment With Progesterone On The Timing And Synchrony Of Ovulation In Bos Indicus Heifers Treated With A Norgestomet Implant For 17 Days, J. Cavalieri, J. E. Kinder, L. A. Fitzpatrick Jan 1998

Effect Of Acute Treatment With Progesterone On The Timing And Synchrony Of Ovulation In Bos Indicus Heifers Treated With A Norgestomet Implant For 17 Days, J. Cavalieri, J. E. Kinder, L. A. Fitzpatrick

Department of Animal Science: Faculty Publications

The aim of the present study was to develop a treatment protocol for the precise synchronization of oestrus that would avoid the development of persistent dominant ovarian follicles. Bos indicus heifers, in which oestrous cycles had been presynchronized, were allocated randomly, according to the day of their oestrous cycle, to one of five treatment groups. All heifers received a subcutaneous ear implant containing 3 mg of norgestomet for 17 days starting on day 0 and an injection of an analogue of prostaglandin F2α on days 0 and 4. Heifers in group 1 (control group; n = 7) received no …

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Expression Of An Inter-Α-Trypsininhibitor Heavy Chain-Like Protein In The Pig Endometrium During The Oestrous Cycle And Early Pregnancy, R. D. Geisert, J. V. Yelich, T. Pratt, Daniel Pomp Jan 1998

Expression Of An Inter-Α-Trypsininhibitor Heavy Chain-Like Protein In The Pig Endometrium During The Oestrous Cycle And Early Pregnancy, R. D. Geisert, J. V. Yelich, T. Pratt, Daniel Pomp

Department of Animal Science: Faculty Publications

In pigs, changes in an unidentified endometrial glycoprotein, pGP30, are temporally associated with rapid trophoblast elongation and initial placental attachment on day 12 of gestation. Identification of endometrial pGP30 was undertaken through protein purification, NH2-terminal amino acid sequencing and cDNA sequencing of products generated through reverse transcription-polymerasechain reaction. Sequencing of 35 amino acids from the NH2-terminal end of pGP30 revealed that the 30 kDa glycoprotein is a cleavage product from the C-terminal region of inter-α-trypsininhibitor heavy chain 4 (IαIH4), previously known as inter-α-trypsininhibitor heavy chain-like protein. IαIH4 is unique compared with the three other inter-α-trypsininhibitor heavy chains as it does …

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Effect Of Ignoring Random Sire And Dam Effects On Estimates And Standard Errors Of Breed Comparisons, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff Jan 1998

Effect Of Ignoring Random Sire And Dam Effects On Estimates And Standard Errors Of Breed Comparisons, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff

Department of Animal Science: Faculty Publications

Data were weights of F1 calves and weaning weights of top-cross progeny from sires and maternal grandsires of 13 breeds. Three analyses were performed on each trait to obtain estimates and standard errors of breed effects needed to calculate across-breed EPD and accuracies. Model (R) for records of F1 progeny contained fixed effects for birth year and date of birth, sex, age and breed of dam, and breed of sire, and a random residual effect. The second analysis included random effects for sires (RS), and the third analysis included random effects for sires and dams (RSD). In maternal …

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Variances Of Direct Genetic Effects, Maternal Genetic Effects, And Cytoplasmic Inheritance Effects For Milk Yield, Fat Yield, And Fat Percentage, L. G. Albuquerque, Jeffrey F. Keown, L. Dale Van Vleck Jan 1998

Variances Of Direct Genetic Effects, Maternal Genetic Effects, And Cytoplasmic Inheritance Effects For Milk Yield, Fat Yield, And Fat Percentage, L. G. Albuquerque, Jeffrey F. Keown, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Milk yield, fat yield, and fat percentage during the first three lactations were studied using New York Holsteins that were milked twice daily over a 305-d, mature equivalent lactation. Those data were used to estimate variances from direct and maternal genetic effects, cytoplasmic effects, sire by herd interaction, and cow permanent environmental effects. Cytoplasmic line was traced to the last female ancestor using DHI records from 1950 through 1991. Records were 138,869 lactations of 68,063 cows calving from 1980 through 1991. Ten random samples were based on herd code. Samples averaged 4926 dams and 2026 cytoplasmic lines. Model also included …

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Calculation Of Breed Direct And Maternal Genetic Fractions And Breed Specific Direct And Maternal Heterozygosity For Crossbreeding Data, L. Dale Van Vleck Dec 1997

Calculation Of Breed Direct And Maternal Genetic Fractions And Breed Specific Direct And Maternal Heterozygosity For Crossbreeding Data, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Teaching, research, and herd breeding applications may require calculation of breed additive contributions for direct and maternal genetic effects and fractions of heterozygosity associated with breed specific direct and maternal heterosis effects. These coefficients can be obtained from the first NB rows of a pseudo numerator relationship matrix where the first NB rows represent fractional contributions by breed to each animal or group representing a specific breed cross. The table begins with an NB x NB identity matrix representing pure breeds. Initial animals or representative crosses must be purebreds or two-breed crosses. Parents of initial purebreds are represented by the …

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Influence Of Dominance Relationships On The Estimation Of Dominance Variance With Sire-Dam Subclass Effects, N. Gengler, L. Dale Van Vleck, M. D. Macneil, I. Misztal, F. A. Pariacote Jul 1997

Influence Of Dominance Relationships On The Estimation Of Dominance Variance With Sire-Dam Subclass Effects, N. Gengler, L. Dale Van Vleck, M. D. Macneil, I. Misztal, F. A. Pariacote

Department of Animal Science: Faculty Publications

Two data sets from the USDA Livestock and Range Research Laboratory were analyzed to study dominance variance and the influence of dominance relationships. The first consisted of 4,155 birth weight (3,884 weaning weight) records of inbred USDA Line 1 Herefords. The second consisted of 8,065 birth weight (7,380 weaning weight) records from a line-cross experiment with five lines. Two models were used. Both included fixed effects of year-sex of calf and age of dam, and covariates for calving date, inbreeding of animal, and inbreeding of dam. For the second set, additional covariates were line composition and heterozygosity coefficients. Random effects …

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Relationships Between In Situ Protein Degradability And Grass Developmental Morphology, R. B. Mitchell, D. D. Redfearn, Lowell E. Moser, R. J. Grant, K. J. Moore, B. H. Kirch Jun 1997

Relationships Between In Situ Protein Degradability And Grass Developmental Morphology, R. B. Mitchell, D. D. Redfearn, Lowell E. Moser, R. J. Grant, K. J. Moore, B. H. Kirch

Department of Animal Science: Faculty Publications

The objective of this research was to determine the relationships between the morphological development and in situ ruminally degradable protein (RDP), ruminally undegradable protein (RUP), and microbial protein of two cool season grasses (intermediate wheatgrass and smooth bromegrass) and two warm season grasses (switchgrass and big bluestem). The initial growth of grass tillers grown near Mead, Nebraska was clipped at ground level six times during the 1992 growing season and morphologically classified. Mean stage was calculated. Forage was ground to pass a 2-mm screen and was incubated in ruminally fistulated steers for 16 h. The RUP was adjusted for microbial …

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Evidence For Quantitative Trait Loci Affecting Ovulation Rate In Pigs, Thomas A. Rathje, G. A. Rohrer, R. K. Johnson May 1997

Evidence For Quantitative Trait Loci Affecting Ovulation Rate In Pigs, Thomas A. Rathje, G. A. Rohrer, R. K. Johnson

Department of Animal Science: Faculty Publications

Fifty-five microsatellite markers were scored in an F2 population of pigs (n = 114 females) developed at the University of Nebraska. The population was produced by crossing a line previously selected for 10 generations using an index of ovulation rate and embryonal survival and a line selected at random. The lines were from a common base population and differed by 6.7 ovulations and 3.1 fetuses at 50 d of gestation. Ovulation rate and number of fully formed and mummified pigs were recorded for each female. Data were analyzed with regression models that included random animal effects. Likelihood-ratio tests were …

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Genetic And Environmental Parameters For Ovulation Rate, Twinning Rate, And Weight Traits In A Cattle Population Selected For Twinning, K. E. Gregory, G. L. Bennett, L. Dale Van Vleck, S. E. Echternkamp, Larry V. Cundiff Jan 1997

Genetic And Environmental Parameters For Ovulation Rate, Twinning Rate, And Weight Traits In A Cattle Population Selected For Twinning, K. E. Gregory, G. L. Bennett, L. Dale Van Vleck, S. E. Echternkamp, Larry V. Cundiff

Department of Animal Science: Faculty Publications

A project was implemented in 1981 with the objective of increasing twinning rate in cattle. Daughters of foundation sires had twin calves at a frequency of from 8 to 13%, and foundation females had twin calves at an average frequency of 50%. Data were analyzed on twinning rate, ovulation rate, and weight traits. The h2 of ovulation rate increased from .11 to .38 for a single estrous cycle to the mean of eight estrous cycles. From all data, h2 for single observation of ovulation rate and twinning rate were .10 and .09, respectively. The rg between them …

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Divergent Selection For Heat Loss In Mice: Ii. Correlated Responses In Feed Intake, Body Mass, Body Composition, And Number Born Through Fifteen Generations, Merlyn K. Nielsen, B. A. Freking, L. D. Jones, S. M. Nelson, T. L. Vorderstrasse, B. A. Hussey Jan 1997

Divergent Selection For Heat Loss In Mice: Ii. Correlated Responses In Feed Intake, Body Mass, Body Composition, And Number Born Through Fifteen Generations, Merlyn K. Nielsen, B. A. Freking, L. D. Jones, S. M. Nelson, T. L. Vorderstrasse, B. A. Hussey

Department of Animal Science: Faculty Publications

Divergent selection for heat loss (kcal•kg-.75•d-1) , measured in 9- to 11-wk-old male mice, was conducted for 15 generations. Selection for high (MH) and low (ML) heat loss and unselected control (MC) occurred in each of three replicates for a total of nine unique lines. Feed intake in males was measured during Generations 9 through 15. Body mass at commencement of mating in females and at time of measurement of heat loss in males was recorded. Body fat percentage at 12 wk for animals of Generations 6, 10, and 14 was predicted as a function of …

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Variability In Metabolic Rate, Feed Intake And Fatness Among Selection And Inbred Lines Of Mice, D. E. Moody, Daniel Pomp, Merlyn K. Nielsen Jan 1997

Variability In Metabolic Rate, Feed Intake And Fatness Among Selection And Inbred Lines Of Mice, D. E. Moody, Daniel Pomp, Merlyn K. Nielsen

Department of Animal Science: Faculty Publications

Mouse populations differing in metabolic rate have been developed through selection for high (MH) and low (ML) heat loss (HLOSS), along with randomly selected controls (MC). Objectives of this study were to (a) compare MH, ML and MC lines for HLOSS and correlated traits of feed intake, body composition and organ weights; (b) compare three widely used inbred mouse lines with MH, ML and MC for the same traits ; and (c) investigate potential genotype by diet interaction resulting from feeding diets differing in fat percentage. Heat loss (kcal/day) of MH and ML mice differed by 37% of the mean …

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A Simulation Model Including Ovulation Rate, Potential Embryonic Viability, And Uterine Capacity To Explain Litter Size In Mice: Ii. Responses To Alternative Criteria Of Selection, E. L. De A. Ribeiro, Merlyn K. Nielsen, Kreg A. Leymaster, Gary Bennett Jan 1997

A Simulation Model Including Ovulation Rate, Potential Embryonic Viability, And Uterine Capacity To Explain Litter Size In Mice: Ii. Responses To Alternative Criteria Of Selection, E. L. De A. Ribeiro, Merlyn K. Nielsen, Kreg A. Leymaster, Gary Bennett

Department of Animal Science: Faculty Publications

Direct selection for litter size was compared with selection for ovulation rate, ova success, or uterine capacity and for indexes of ovulation rate with ova success or uterine capacity. Selection was simulated for 10 generations in a mouse population based on a model integrating ovulation rate, potential embryonic viability, and uterine capacity. Two indexes including ovulation rate (OR) and ova success (OS) were I = .291 x OR + 2.19 x OS and I = .165 x OR + .736 x OS. Heritabilities for ovulation rate and ova success, assumed in the simulation and to derive the indexes, were .25 …

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Divergent Selection For Heat Loss In Mice: I. Selection Applied And Direct Response Through Fifteen Generations, Merlyn K. Nielsen, L. D. Jones, B. A. Freking, J. A. Deshazer Jan 1997

Divergent Selection For Heat Loss In Mice: I. Selection Applied And Direct Response Through Fifteen Generations, Merlyn K. Nielsen, L. D. Jones, B. A. Freking, J. A. Deshazer

Department of Animal Science: Faculty Publications

Divergent selection for heat production/ loss (kcal•kg-.75•d-1) , measured in 9- to 11-wk-old male mice, was conducted for 15 generations. Heat loss was measured for 15 h on individual animals placed overnight in direct, gradient-layer calorimeters. Selection for high (MH) and low (ML) heat loss and unselected control (MC) occurred in each of three replicates for a total of nine unique lines. Repeatability of the heat loss measurement was .45 and the CV was 10.5%. Cumulative realized selection differentials, averaged for the three replicates, were 145.1 and -105.0 (kcal•kg-.75•d-1) and ranged from …

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