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Department of Animal Science: Faculty Publications

Articles 811 - 840 of 1242

Full-Text Articles in Animal Sciences

Limiting Amino Acids In Meat And Bone And Poultry By-Product Meals, M. J. Klemesrud, Terry Klopfenstein, Austin Lewis, D. H. Shain, D. Herold Jan 1997

Limiting Amino Acids In Meat And Bone And Poultry By-Product Meals, M. J. Klemesrud, Terry Klopfenstein, Austin Lewis, D. H. Shain, D. Herold

Department of Animal Science: Faculty Publications

In situ, digestion, and growth studies were conducted to evaluate four meat and bone meals and six poultry by-product meals as sources of escape protein and to predict the first-limiting amino acid for growing calves. Escape protein values, determined by 12-h in situ incubation, ranged from 41.7 to 51.0% of CP for meat and bone meals; poultry by-product meals ranged from 32.0 to 39.8%. True protein digestion in the gastrointestinal tract of lambs differed among protein sources ( P < .05), ranging from 79 to 95%. In each of three growth trials, 60 steers (258 ± 24, 241 ± 23, and 230 ± 16 kg for Trials 1, 2, and 3, respectively) were supplemented with 4 of the 10 protein sources along with a urea supplement. Protein sources were fed at 30, 40, 50, and 60% of the supplemental CP, with urea supplying the remainder. Protein efficiency differed among treatments ( P < .10), ranging from .61 to 1.55. Amino acid composition was determined for each protein source, and the individual metabolizable amino acids were regressed on the protein efficiency values. Escape protein values were correlated (R2 = .75) with protein efficiency but had a negative slope. Metabolizable methionine was the only amino acid moderately correlated (R …

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Development Of Gilts And Boars For Efficient Reproduction, Donald G. Levis, Vernon D. Leibbrandt, Dale W. Rozeboom Jan 1997

Development Of Gilts And Boars For Efficient Reproduction, Donald G. Levis, Vernon D. Leibbrandt, Dale W. Rozeboom

Department of Animal Science: Faculty Publications

Successful introduction of replacement gilts and boars into the breeding herd is an important aspect of breeding herd efficiency. To attain herd efficiency, females must ovulate adequate numbers of viable ova, express estrus, show willingness to mate, and conceive in a regular manner. Males must produce adequate numbers of fertile spermatozoa, possess ability and show willingness to mate, and produce high-conception rates. If these qualities are properly developed, pregnancy rate and litter size will be maximized.

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A Simulation Model Including Ovulation Rate, Potential Embryonic Viability, And Uterine Capacity To Explain Litter Size In Mice: I. Model Development And Implementation, E. L. De A. Ribeiro, Merlyn K. Nielsen, Gary Bennett, Kreg A. Leymaster Jan 1997

A Simulation Model Including Ovulation Rate, Potential Embryonic Viability, And Uterine Capacity To Explain Litter Size In Mice: I. Model Development And Implementation, E. L. De A. Ribeiro, Merlyn K. Nielsen, Gary Bennett, Kreg A. Leymaster

Department of Animal Science: Faculty Publications

Litter size in mice was studied using a model including ovulation rate, potential embryonic viability, and uterine capacity. Simulated results were compared with experimental results from a selection experiment with mice. The four criteria of selection were selection on number born (LS), selection on an index of ovulation rate and ova success (IX), selection on number born to unilaterally ovariectomized females (UT), and unselected control (LC). Comparisons were made to statistics of the base generation and to responses after 13 generations of selection. Phenotypic and genetic statistics for uterine capacity were generated so that simulations produced the experimental means, standard …

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Effects Of Sire, Dam Traits, Calf Traits, And Environment On Dystocia And Subsequent Reproduction Of Two-Year-Old Heifers, D. J. Colburn, Gene H. Deutscher, Merlyn K. Nielsen, Don C. Adams Jan 1997

Effects Of Sire, Dam Traits, Calf Traits, And Environment On Dystocia And Subsequent Reproduction Of Two-Year-Old Heifers, D. J. Colburn, Gene H. Deutscher, Merlyn K. Nielsen, Don C. Adams

Department of Animal Science: Faculty Publications

A study was conducted over 3 yr to evaluate effects of sire birth weight EPD, calf birth weight and shape, and heifer pelvic area and weight, individually and in combination, on dystocia and subsequent rebreeding of 2-yr-old heifers. Heifers (n = 550), MARC II yearlings, were assigned for breeding to one of four Angus sires with birth weight EPD of -.95, -.82, +2.9, and +2.7 kg. At calving, heifers were assisted as needed. A gauge attached to the calf puller recorded applied traction pressure. Analysis of traction pressure detected only slightly larger amounts of variation (2 to 3%) affecting dystocia …

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Influence Of Sample Orientation On Prediction Of Fresh Ham Lean Content By Electromagnetic Scanning, N. L. Meseck, B. L. Gwartney, Chris R. Calkins, Phillip Miller Jan 1997

Influence Of Sample Orientation On Prediction Of Fresh Ham Lean Content By Electromagnetic Scanning, N. L. Meseck, B. L. Gwartney, Chris R. Calkins, Phillip Miller

Department of Animal Science: Faculty Publications

To evaluate the effect of orientation of hams during electromagnetic scanning on the estimation of dissected lean content, hams were scanned horizontally, posterior first (POS) or dorsal first (DOR), and vertically, medial side (aitchbone) first (MED; standing on the butt face). Weight and percentage of dissected lean were estimated using scan peak for each orientation, ham weight, and fat thickness. The mean scan peak for the MED orientation was approximately twice as great as peaks for the POS and DOR orientations, which suggests that this orientation may offer greater predictive accuracy by reducing the signal to noise ratio. Results, however, …

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Comparison Of Usda Quality Grade With Tendertec For The Assessment Of Beef Palatability, M. H. George, J.D. Tatum, H. G. Dolezal, J. B. Morgan, J. M. Wise, Chris R. Calkins, T. Gordon, J. O. Reagan, G. C. Smith Jan 1997

Comparison Of Usda Quality Grade With Tendertec For The Assessment Of Beef Palatability, M. H. George, J.D. Tatum, H. G. Dolezal, J. B. Morgan, J. M. Wise, Chris R. Calkins, T. Gordon, J. O. Reagan, G. C. Smith

Department of Animal Science: Faculty Publications

Carcasses (n = 265) selected to differ in USDA yield grade were evaluated by expert graders and assessed for tenderness with the Tendertec Mark III Beef Grading Instrument. Tendertec measurements were collected on longissimus lumborum muscles in both sides of each carcass. During fabrication of each left carcass side, a rib section (later converted into three steaks) was removed for aging and subsequent sensory panel evaluation at 14 d and for Warner-Bratzler shear force measurements at 14 and 28 d. Correlation coefficients for repeatability of Tendertec output variables, between left and right carcass sides, were .57, .44, .70, and .65 …

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Role Of Basic-Helix-Loop-Helix Transcription Factors In Sertoli Cell Differentiation: Identification Of An E-Box Response Element In The Transferrin Promoter, Jaideep Chaudhary, Andrea S. Cupp, Michael K. Skinner Jan 1997

Role Of Basic-Helix-Loop-Helix Transcription Factors In Sertoli Cell Differentiation: Identification Of An E-Box Response Element In The Transferrin Promoter, Jaideep Chaudhary, Andrea S. Cupp, Michael K. Skinner

Department of Animal Science: Faculty Publications

Sertoli cells are critical for testicular function and maintenance of the spermatogenic process. The induction of Sertoli cell differentiation in the embryo promotes testicular development and male sex determination. The progression of Sertoli cell differentiation during puberty promotes the onset of spermatogenesis. The maintenance of optimal Sertoli cell differentiation in the adult is required for spermatogenesis to proceed. The current study was designed to investigate the transcriptional regulation of Sertoli cell differentiation through the analysis of a previously identified marker of differentiation, transferrin gene expression. Sertoli cells produce transferrin to transport iron to developing spermatogenic cells sequestered within the blood-testis …

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Estimation Of Direct And Maternal Breed Effects For Prediction Of Expected Progeny Differences For Birth And Weaning Weights In Three Multibreed Populations, F. A. Rodriguez-Almeida, L. Dale Van Vleck, K. E. Gregory Oct 1996

Estimation Of Direct And Maternal Breed Effects For Prediction Of Expected Progeny Differences For Birth And Weaning Weights In Three Multibreed Populations, F. A. Rodriguez-Almeida, L. Dale Van Vleck, K. E. Gregory

Department of Animal Science: Faculty Publications

Direct and maternal breed effects on birth and 200-d weights were estimated for nine parental breeds (Hereford [H], Angus [A], Braunvieh [B], Limousin [L], Charolais [C], Simmental [S], Gelbvieh [G], Red Poll [R], and Pinzgauer [P]) that contributed to three composite populations (MARC I = ¼B, ¼C, ¼L, ⅛H, ⅛A; MARC II = ¼G, ¼S, ¼H, ¼A; and MARC III = ¼R, ¼P, ¼H, ¼A). Records from each population, the composite plus pure breeds and crosses used to create each composite, were analyzed separately. The animal model included fixed effects of contemporary group (birth year-sex-dam age), proportions of individual and …

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Comparison Of Circulating Concentrations Of Reproductive Hormones In Boars Of Lines Selected For Size Of Testes Or Number Of Ovulations And Embryonal Survival To Concentrations In Respective Control Lines, D. V. Mariscal, P. L. Wolfe, E. G. M. Bergfeld, A. S. Cupp, F. N. Kojima, K. E. Fike, T. Sanchez, M. E. Wehrman, R. K. Johnson, R. J. Kittock, J. J. Ford, J. E. Kinder Oct 1996

Comparison Of Circulating Concentrations Of Reproductive Hormones In Boars Of Lines Selected For Size Of Testes Or Number Of Ovulations And Embryonal Survival To Concentrations In Respective Control Lines, D. V. Mariscal, P. L. Wolfe, E. G. M. Bergfeld, A. S. Cupp, F. N. Kojima, K. E. Fike, T. Sanchez, M. E. Wehrman, R. K. Johnson, R. J. Kittock, J. J. Ford, J. E. Kinder

Department of Animal Science: Faculty Publications

The objectives of this study were to determine whether circulating concentrations of gonadotropins and gonadal hormones of boars were altered as a result of selection of pigs for size of testes or for embryonal survival and(or) number of ovulations. Included in Exp. 1 and 2 were boars with the greatest estimated paired weight of testes (TS) and boars from a control (C) line. Concentrations of FSH were similar (P > .10) in boars from the TS and C lines. In Exp. 3, 4, and 5, circulating concentrations of FSH and 17β-estradiol (E2) were evaluated in neonates, during pubertal …

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Prediction Of Breeding Values For Tenderness Of Market Animals From Measurements On Bulls, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff, M. Koohamaraie, D. D. Lunstra, J. D. Crouse Jul 1996

Prediction Of Breeding Values For Tenderness Of Market Animals From Measurements On Bulls, K. L. Barkhouse, L. Dale Van Vleck, Larry V. Cundiff, M. Koohamaraie, D. D. Lunstra, J. D. Crouse

Department of Animal Science: Faculty Publications

Data were tenderness measures on steaks from 237 bulls (Group II) slaughtered after producing freezable semen and on 1,431 related steers and heifers (market animals, Group I ) from Angus, Hereford, Pinzgauer, Brahman, and Sahiwal crosses from the Germ Plasm Evaluation project at the U.S. Meat Animal Research Center. Tenderness was assessed through Warner-Bratzler Shear Force (SF), taste panel tenderness (TPT), marbling score (MS), and myofibrillar fragmentation index (MFI). For all traits, as fraction Bos indicus inheritance increased, implied tenderness decreased. Heritability estimates were generally not significantly different from zero. Genetic correlations generally indicated favorable associations among the traits. The …

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Comparison Of Circulating Concentrations Of Reproductive Hormones In Boars Of Lines Selected For Size Of Testes Or Number Of Ovulations And Embryonal Survival To Concentrations In Respective Control Lines, D. V. Mariscal, P. L. Wolfe, E. G. M. Bergfeld, Andrea S. Cupp, F. N. Kojima, K. E. Fike, T. Sanchez, M. E. Wehrman, Rodger K. Johnson, Roger J. Kittok, J. J. Ford, J. E. Kinder Jul 1996

Comparison Of Circulating Concentrations Of Reproductive Hormones In Boars Of Lines Selected For Size Of Testes Or Number Of Ovulations And Embryonal Survival To Concentrations In Respective Control Lines, D. V. Mariscal, P. L. Wolfe, E. G. M. Bergfeld, Andrea S. Cupp, F. N. Kojima, K. E. Fike, T. Sanchez, M. E. Wehrman, Rodger K. Johnson, Roger J. Kittok, J. J. Ford, J. E. Kinder

Department of Animal Science: Faculty Publications

The objectives of this study were to determine whether circulating concentrations of gonadotropins and gonadal hormones of boars were altered as a result of selection of pigs for size of testes or for embryonal survival and(or) number of ovulations. Included in Exp. 1 and 2 were boars with the greatest estimated paired weight of testes (TS) and boars from a control (C) line. Concentrations of FSH were similar ( P > .10) in boars from the TS and C lines. In Exp. 3, 4, and 5, circulating concentrations of FSH and 17β-estradiol (E2) were evaluated in neonates, during pubertal …

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Progestin And Estrogen Regulation Of Pulsatile Lh Release And Development Of Persistent Ovarian Follicles In Cattle, J. E. Kinder, F. N. Kojima, E. G. M. Bergfeld, M. E. Wehrman, K. E. Fike May 1996

Progestin And Estrogen Regulation Of Pulsatile Lh Release And Development Of Persistent Ovarian Follicles In Cattle, J. E. Kinder, F. N. Kojima, E. G. M. Bergfeld, M. E. Wehrman, K. E. Fike

Department of Animal Science: Faculty Publications

When doses of progestin used commercially are administered to synchronize the stage of the estrous cycle among bovine females, fertility is reduced compared with that of untreated controls. The reduced fertility that results from the use of progestinbased estrus synchrony regimens is associated with the development of persistent ovarian follicles. Persistent ovarian follicles develop as a result of the greater frequency of LH pulses that occurs during the period of treatment with progestins. The greater release of LH pulses results in enhanced secretion of 17β-estradiol from persistent ovarian follicles. The greater frequency of LH release or the greater secretion of …

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Multiple-Trait Gibbs Sampler For Animal Models: Flexible Programs For Bayesian And Likelihood-Based (Co)Variance Component Inference, C. P. Van Tassell, L. Dale Van Vleck May 1996

Multiple-Trait Gibbs Sampler For Animal Models: Flexible Programs For Bayesian And Likelihood-Based (Co)Variance Component Inference, C. P. Van Tassell, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

A set of FORTRAN programs to implement a multiple-trait Gibbs sampling algorithm for (co)variance component inference in animal models (MTGSAM) was developed. The MTGSAM programs are available to the public. The programs support models with correlated genetic effects and arbitrary numbers of covariates, fixed effects, and independent random effects for each trait. Any combination of missing traits is allowed. The programs were used to estimate variance components for 50 replicates of simulated data. Each replicate consisted of 50 animals of each sex in each of four generations, for 400 animals in each replicate for two traits. For MTGSAM, informative prior …

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Direct And Maternal Genetic Covariances By Age Of Dam For Weaning Weight, L. Dale Van Vleck, K. E. Gregory, G. L. Bennett Mar 1996

Direct And Maternal Genetic Covariances By Age Of Dam For Weaning Weight, L. Dale Van Vleck, K. E. Gregory, G. L. Bennett

Department of Animal Science: Faculty Publications

Weaning weights of calves of dams at ages in years of 2, 3, and older were modeled to be three separate traits. Fixed effects were sex of calfyear of birth combinations for nine pure breeds and sex of calf-year of birth-generation for three composite populations. Random effects fitted for each trait were correlated direct and maternal genetic, maternal permanent environmental, and temporary environmental. Direct and maternal effects were correlated across traits. A multiple-trait, derivative-free REML algorithm was used to estimate the 30 (co)variance components. Number of animals per breed group ranged from 1,244 to 4,326. For the three traits for …

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Estimation Of Variances Due To Direct And Maternal Effects For Growth Traits Of Nelore Cattle, J. P. Eler, L. Dale Van Vleck, J. B. S. Ferraz, R. B. Lobo Mar 1996

Estimation Of Variances Due To Direct And Maternal Effects For Growth Traits Of Nelore Cattle, J. P. Eler, L. Dale Van Vleck, J. B. S. Ferraz, R. B. Lobo

Department of Animal Science: Faculty Publications

Estimates of (co)variance components and genetic parameters were obtained for birth, 205-d, and 365-d weight for Nelore cattle in Brazil, using single and multiple-trait animal models. Data were from the Brazilian Zebu Breeders Association (ABCZ). Records of 27,549 calves sired by 587 bulls and raised on pasture in 57 herds were analyzed by restricted maximum likelihood fitting an animal model including direct and maternal genetic and permanent environmental effects. Single and multiple- trait analyses were carried out. Heritability estimates for direct effects were lower than previous values reported for the Nelore breed. The estimates for maternal genetic effects showed that …

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Effect Of Selection For Size Of Testes In Boars On Semen And Testis Traits, Ying-Tsorn Huang, Rodger K. Johnson Mar 1996

Effect Of Selection For Size Of Testes In Boars On Semen And Testis Traits, Ying-Tsorn Huang, Rodger K. Johnson

Department of Animal Science: Faculty Publications

The objective of this study was to evaluate the effects of selection for increased size of testes on semen and testis characteristics. Boars from a line selected for increased size of testes at 150 d of age (TS, n = 25) and a randomly selected control line (C, n = 18) were used. Semen was collected three times per week for 3 wk (TRT1) then daily for 3 wk (TRT2) beginning when boar age averaged 276 d. It was followed by a 4-wk period of one collection per week and then the TRT1-TRT2 sequence was repeated. After 64 collections, boars …

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Variances Of Additive And Dominance Genetic Effects For Ovulation And Twinning Rates In A Population Selected For Twinning, L. Dale Van Vleck, K. E. Gregory Jan 1996

Variances Of Additive And Dominance Genetic Effects For Ovulation And Twinning Rates In A Population Selected For Twinning, L. Dale Van Vleck, K. E. Gregory

Department of Animal Science: Faculty Publications

Estimates of variances due to additive and dominance genetic effects and permanent and temporary environmental effects were obtained for ovulation and twinning rates from a composite population selected for twinning rate. Measures of ovulation rate after 11 mo of age on 2,317 heifers with a total of 19,209 measures were used. Twinning measures were on 1,522 first-parity cows, 1,311 later-parity cows with a total of 3,571 measures, and 1,704 all-parity cows with 5,100 measures. Models included fixed effects of year-season-age at calving for twinning, and year-season of birth, age in months, and calendar month of measurement for ovulation rate. Four …

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Ewe Fertility In The Star Accelerated Lambing System, R. M. Lewis, D. R. Notter, D. E. Hogue, B. H. Magee Jan 1996

Ewe Fertility In The Star Accelerated Lambing System, R. M. Lewis, D. R. Notter, D. E. Hogue, B. H. Magee

Department of Animal Science: Faculty Publications

Effects of environmental factors such as ewe age, season of exposure, and time from lambing to exposure on fertility were evaluated using records on 1,084 Dorset ewes in the STAR accelerated lambing system. The STAR program consisted of five 30-d concurrent breeding and lambing periods per year beginning on January 1, March 15, May 27, August 8, and October 20. Fertility in the flock changed in a cyclic and predictable fashion during the year. Changes in prolificacy were less consistent but also tended to show cyclic variation. Matings that occurred within the typical breeding season (August, October, and January) were …

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Embryonal Survival To 6 Days In Mice Selected On Different Criteria For Litter Size, E. L. De A. Ribeiro, M. A. J. Van Engelen, Merlyn K. Nielsen Jan 1996

Embryonal Survival To 6 Days In Mice Selected On Different Criteria For Litter Size, E. L. De A. Ribeiro, M. A. J. Van Engelen, Merlyn K. Nielsen

Department of Animal Science: Faculty Publications

Embryonal survival was compared in mice resulting from four criteria of selection: LS = selection on number born; IX = selection on an index of ovulation rate and ova success; UT = selection on number born to unilaterally ovariectomized females; and LC = unselected control. Selection occurred for 21 generations with three replicates of the four criteria; thereafter, relaxed selection was practiced. The evaluation was performed using mice of two replicates at Generation 35 and one replicate at Generation 36. Data on a total of 289 female mice were recorded. Females, at an average age of 9 wk, were mated …

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Effect Of Variance Of Interaction Effects Of Sire And Herd On Selection For Milk And Fat Yield, G. Dimov, Jeffrey F. Keown, L. Dale Van Vleck, H. D. Norman Jan 1996

Effect Of Variance Of Interaction Effects Of Sire And Herd On Selection For Milk And Fat Yield, G. Dimov, Jeffrey F. Keown, L. Dale Van Vleck, H. D. Norman

Department of Animal Science: Faculty Publications

The animal model for genetic evaluations of dairy cattle by the USDA currently includes a term for interaction effects of sire and herd. The relative magnitude of the variance of that effect was established in the 1960s as 14% of the total variance, but recent research has shown that the proportion is 2% or less. This report compared EBV using either the 14% or the actual estimate from 20 samples of records from herds in California, New York, and Pennsylvania. From 6 to 22% of bulls or cows selected for milk and fat yields based on evaluation with 14% of …

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Use Of Expected Progeny Differences For Marbling In Beef: I. Production Traits, B. A. Vieselmeyer, Richard J. Rasby, B. L. Gwartney, Chris R. Calkins, Rick Stock, James A. Gosey Jan 1996

Use Of Expected Progeny Differences For Marbling In Beef: I. Production Traits, B. A. Vieselmeyer, Richard J. Rasby, B. L. Gwartney, Chris R. Calkins, Rick Stock, James A. Gosey

Department of Animal Science: Faculty Publications

Six Angus bulls with HIGH (>.4) and six bulls with LOW (<-.16) expected progeny differences (EPD) for marbling were used to evaluate the impact of marbling on progeny production and carcass traits. Bulls were randomly bred to MARC II (¼ Hereford, ¼ Simmental, ¼ Angus, ¼ Gelbvieh) composite cows in each of 2 yr to calve in the spring. At weaning, steers and heifers were separated and managed in different production systems. Steers (n = 131) were fed a growing diet (1.1 Mcal of NEg/kg) for 48 d followed by adaptation to a 93% concentrate finishing diet. Heifers (n = 125) were fed a growing diet (.79 Mcal of NEg/kg) for 191 d followed by adaptation to the same 93% concentrate diet. Steers and heifers from each treatment were slaughtered at two times spaced about 60 d apart within both years. Marbling EPD class had no effect on fat thickness, USDA yield grade, carcass weight, finishing daily gain, finishing DMI, or finishing efficiency ( P > .18). More ( …

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Use Of Expected Progeny Differences For Marbling In Beef: Ii. Carcass And Palatability Traits, B. L. Gwartney, Chris R. Calkins, Richard J. Rasby, Rick Stock, B. A. Vieselmeyer, James A. Gosey Jan 1996

Use Of Expected Progeny Differences For Marbling In Beef: Ii. Carcass And Palatability Traits, B. L. Gwartney, Chris R. Calkins, Richard J. Rasby, Rick Stock, B. A. Vieselmeyer, James A. Gosey

Department of Animal Science: Faculty Publications

A 2-yr study was conducted to determine the effect of EPD for marbling on marbling score, palatability traits, and carcass fatness in beef. Steer (n = 122) and heifer (n = 123) carcasses were obtained by mating Angus bulls having a high (>.4) or low (<-.16) EPD for marbling to MARC II cows (¼ Angus, ¼ Hereford, ¼ Simmental, and ¼ Gelbvieh). Carcass traits, composition of primals, quarters, and sides, palatability, and shear force data were obtained and adjusted to the mean number of days on feed, equal marbling score (Small50) , fat thickness (1.0 cm), and carcass weight (318 kg) end points. Steer carcasses from the high marbling EPD group, adjusted to the mean number of days on feed, had significantly more marbling ( P < .01) and less subcutaneous fat in the side and the hindquarter ( P < .10) than their low marbling EPD counterparts. Adjusting steers to Small50 marbling produced smaller longissimus muscle area (by 5 cm2) , less fat thickness (1.15 vs 1.28 cm), and lighter side weights (306 vs …

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Changing Dose Of Progesterone Results In Sudden Changes In Frequency Of Luteinizing Hormone Pulses And Secretion Of 17Β-Estradiol In Bovine Females, E. G. M. Bergfeld, F. N. Kojima, Andrea S. Cupp, M. E. Wehrman, K. E. Peters, V. Mariscal, T. Sanchez, J. E. Kinder Jan 1996

Changing Dose Of Progesterone Results In Sudden Changes In Frequency Of Luteinizing Hormone Pulses And Secretion Of 17Β-Estradiol In Bovine Females, E. G. M. Bergfeld, F. N. Kojima, Andrea S. Cupp, M. E. Wehrman, K. E. Peters, V. Mariscal, T. Sanchez, J. E. Kinder

Department of Animal Science: Faculty Publications

The aim of the present study was to elucidate the time course according to which changes in circulating concentrations of progesterone influence pulsatile secretion of LH and secretion of 17β-estradiol. Our working hypothesis was that changing the dose of progesterone would result in changes in frequency of LH pulses and secretion of 17β-estradiol within 72 h. Five days after behavioral estrus, thirty-three cows were randomly assigned to one of five groups: 1) control, no treatment (CONT, n = 5); 2) treatment with two progesterone-releasing intravaginal devices (PRIDs) for 11 days (2PRID, 5-6 ng/ml plasma progesterone, n = 7); 3) treatment …

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Transcriptional Regulation Of Sertoli Cell Differentiation By Follicle-Stimulating Hormone At The Level Of The C-Fos And Transferrin Promoters, Jaideep Chaudary, Patricia D. Whaley, Andrea S. Cupp, Michael K. Skinner Jan 1996

Transcriptional Regulation Of Sertoli Cell Differentiation By Follicle-Stimulating Hormone At The Level Of The C-Fos And Transferrin Promoters, Jaideep Chaudary, Patricia D. Whaley, Andrea S. Cupp, Michael K. Skinner

Department of Animal Science: Faculty Publications

One of the primary endocrine hormones that influence the onset of Sertoli cell differentiation at puberty and help maintain differentiation in the adult testis is FSH. FSH can modulate the majority of Sertoli cell differentiated functions, including stimulation of the iron-binding protein transferrin. Previous studies have shown that FSH alters the levels of cAMP and the immediate early gene c-fos. The current study was designed to investigate the transcriptional regulation of Sertoli cell differentiation by examining the actions of FSH on the promoter of the immediate early gene c-fos and the promoter of the downstream differentiated function gene transferrin. …

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Genetic Trend And Environmental Effects In A Population Of Cattle Selected For Twinning, L. Dale Van Vleck, K. E. Gregory Jan 1996

Genetic Trend And Environmental Effects In A Population Of Cattle Selected For Twinning, L. Dale Van Vleck, K. E. Gregory

Department of Animal Science: Faculty Publications

A selection experiment was established in 1981 to increase twinning rate in cattle. Results reported are through 1993 calf crops. Estimates of genetic parameters for a two-trait twinning and ovulation rate model with genetic groups were as follows: heritabilities of .03 for twinning and .07 for ovulation rates with a genetic correlation of nearly 1.00 and fractional permanent environmental variances of .06 for twinning and .05 for ovulation rate. Corresponding estimates when group effects were ignored were as follows: heritabilities of .08 and .08 and fractional permanent environmental variances of .02 and .04 for twinning and ovulation rates, respectively. Twinning …

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Estimates Of Heritabilities And Genetic And Environmental Correlations For Left- And Right-Side Uterine Capacity And Ovulation Rate In Mice, Merlyn K. Nielsen, Y. L. Kochera Kirby, A. C. Clutter Jan 1996

Estimates Of Heritabilities And Genetic And Environmental Correlations For Left- And Right-Side Uterine Capacity And Ovulation Rate In Mice, Merlyn K. Nielsen, Y. L. Kochera Kirby, A. C. Clutter

Department of Animal Science: Faculty Publications

Heritabilities for and genetic and environmental correlations between uterine capacity, ovulation rate, and body mass (BM) were estimated in mice. Uterine capacity was defined as the number of fetuses (LUC or RUC for left or right side) in one uterine horn for unilaterally ovariectomized females. Ovulation rate (corpora lutea, LCL or RCL for left or right ovary) was measured on the remaining single ovary in these same females. Data on 1,931 mice from four selection populations were used. Left ovulation rate and LUC were measured on 958 animals, and RCL and RUC of another 972 animals were recorded. Genetic and …

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Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska Oct 1995

Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska

Department of Animal Science: Faculty Publications

Weights of testes and epididymides, body weight, and morphometric measurements of testicular tissue of 75 boars of a line selected for eight generations for predicted weight of testes at 150 d of age and 75 boars of a randomly selected control line were used to evaluate the effects of selection on testicular development at 70, 100, 130, 160, and 450 d of age (n = 15 boars per line per age). Body weights for boars of the select and control line did not differ (P <.05) and the shape of the body growth curve was similar for both lines. Boars of the select line had larger testes than control boars at each age (P < .05), but there was a significant line x age interaction. The percentage increase of the select line mean over the control mean for weight of testes was 37% at 70 d, a maximum of 120% at 100 d, and 25% at 450 d. The percentage of the testes made up of seminiferous tubules differed between lines (P <.01). Lines had similar means of approximately 28% at 70 d and 71% at 450 d, but the mean for the select line was larger between 100 and 160 d of age; the greatest difference was 11.6% (control = 43.7, select = 55.3%) at 100 d. After 70 d of age, select-line boars had a greater percentage of seminiferous tubules with lumens that contained elongated spermatids (P <.l0). The proportion of the testes occupied by Leydig cells was greatest at 70 d, declined sharply between 70 and 130 d with a sharper decline in select-line boars, and then declined more gradually from 130 to 450 d of age. We conclude that selection for weight of testes at 150 d resulted in lower age at puberty for boars of the select line.

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Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska Oct 1995

Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska

Department of Animal Science: Faculty Publications

Weights of testes and epididymides, body weight, and morphometric measurements of testicular tissue of 75 boars of a line selected for eight generations for predicted weight of testes at 150 d of age and 75 boars of a randomly selected control line were used to evaluate the effects of selection on testicular development at 70, 100, 130, 160, and 450 d of age (n = 15 boars per line per age). Body weights for boars of the select and control line did not differ (P <.05) and the shape of the body growth curve was similar for both lines. Boars of the select line had larger testes than control boars at each age (P < .05), but there was a significant line x age interaction. The percentage increase of the select line mean over the control mean for weight of testes was 37% at 70 d, a maximum of 120% at 100 d, and 25% at 450 d. The percentage of the testes made up of seminiferous tubules differed between lines (P <.01). Lines had similar means of approximately 28% at 70 d and 71% at 450 d, but the mean for the select line was larger between 100 and 160 d of age; the greatest difference was 11.6% (control = 43.7, select = 55.3%) at 100 d. After 70 d of age, select-line boars had a greater percentage of seminiferous tubules with lumens that contained elongated spermatids (P <.lo). The proportion of the testes occupied by Leydig cells was greatest at 70 d, declined sharply between 70 and 130 d with a sharper decline in select-line boars, and then declined more gradually from 130 to 450 d of age. We conclude that selection for weight of testes at 150 d resulted in lower age at puberty for boars of the select line.

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Estimation Of Variances Due To Direct And Maternal Effects For Growth Traits Of Nelore Cattle, J. P. Eler, L. Dale Van Vleck, J. B. S. Ferraz, R. B. Lobo May 1995

Estimation Of Variances Due To Direct And Maternal Effects For Growth Traits Of Nelore Cattle, J. P. Eler, L. Dale Van Vleck, J. B. S. Ferraz, R. B. Lobo

Department of Animal Science: Faculty Publications

Estimates of (co)variance components and genetic parameters were obtained for birth, 205-d, and 365-d weight for Nelore cattle in Brazil, using single and multiple-trait animal models. Data were from the Brazilian Zebu Breeders Association (ABCZ). Records of 27,549 calves sired by 587 bulls and raised on pasture in 57 herds were analyzed by restricted maximum likelihood fitting an animal model including direct and maternal genetic and permanent environmental effects. Single and multiple- trait analyses were carried out. Heritability estimates for direct effects were lower than previous values reported for the Nelore breed. The estimates for maternal genetic effects showed that …

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Effect Of Accounting For Different Phenotypic Variances By Sire Breed And Sex On Selection Of Sires Based On Expected Progeny Differences For 200- And 365-Day Weights, F. A. Rodriguez-Almeida, L. Dale Van Vleck, Larry V. Cundiff Apr 1995

Effect Of Accounting For Different Phenotypic Variances By Sire Breed And Sex On Selection Of Sires Based On Expected Progeny Differences For 200- And 365-Day Weights, F. A. Rodriguez-Almeida, L. Dale Van Vleck, Larry V. Cundiff

Department of Animal Science: Faculty Publications

The effects of accounting for different phenotypic variances according to sire breed and sex subclasses on estimation of sire breed effects and prediction of expected progeny differences of sires mated to Hereford and Angus cows were investigated. Data consisted of 6,977 and 6,530 records of 200-d (weaning) and 365-d (yearling) weights, respectively, of F1 calves sired by bulls (662 and 661, respectively) of 23 breeds that have been evaluated in the Germ Plasm Evaluation Program at the U.S. Meat Animal Research Center, Clay Center, NE. Models compared included fixed effects of genetic group of sire (samples of sires evaluated …

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