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Full-Text Articles in Life Sciences
Differences In Heritability Estimates From Multiple-Trait And Repeated-Records Models, L. Dale Van Vleck, K. E. Gregory
Differences In Heritability Estimates From Multiple-Trait And Repeated-Records Models, L. Dale Van Vleck, K. E. Gregory
Department of Animal Science: Faculty Publications
Analyses of ovulation rates in consecutive estrous cycles with multiple-trait and repeated-records animal models resulted in different estimates of heritability. The estimate from the repeated-records model was seen to be approximately the product of the average genetic correlation and the average heritability from the multiple-trait procedure. A simple model is used to show algebraically that such a result is expected particularly if the environmental correlations are small among records of the same animal. Comparison of results of the two types of analyses of 10 replications of 10 combinations of underlying heritabilities and genetic correlations confirms this explanation.
Modulation Of Luteinizing Hormone And Follicle-Stimulating Hormone In Circulation By Interactions Between Endogenous Opioids And Oestradiol During The Peripubertal Period Of Heifers, M. W. Wolfe, M. S. Roberson, T. T. Stumpf, Roger J. Kittok, J. E. Kinder
Modulation Of Luteinizing Hormone And Follicle-Stimulating Hormone In Circulation By Interactions Between Endogenous Opioids And Oestradiol During The Peripubertal Period Of Heifers, M. W. Wolfe, M. S. Roberson, T. T. Stumpf, Roger J. Kittok, J. E. Kinder
Department of Animal Science: Faculty Publications
The aim of this study was to determine whether the decline in oestradiol inhibition of circulating luteinizing hormone (LH) and follicle-stimulating hormone (FSH) during the peripubertal period of heifers is associated with a change in opioid modulation of LH and FSH secretion. Opioid inhibition of LH secretion was determined by response to administration of the opioid antagonist naloxone. Prepubertal heifers (403 days old) were left as intact controls, ovariectomized or ovariectomized and chronically administered oestradiol. Control heifers were used to determine time of puberty. Three weeks after ovariectomy, four doses of naloxone (0·13-0·75 mg kg-1 body weight) or saline …
Genetic Variation Liver Mass, Body Mass, And Liver:Body Mass In Mice, L. D. Jones, Merlyn K. Nielsen, R. Britton
Genetic Variation Liver Mass, Body Mass, And Liver:Body Mass In Mice, L. D. Jones, Merlyn K. Nielsen, R. Britton
Department of Animal Science: Faculty Publications
Genetic variation for liver mass (LM), body mass (BM), and 1iver:body mass (LM/ BM) was examined for outbred populations of laboratory mice. Liver mass and body mass data were collected on 170 pureline sires at 12 wk of age, representing four outbred stocks of laboratory mice; 523 of their male and female two-way cross progeny at 9 or 12 wk; and 214 four-way-cross' offspring at 12, 14, or 16 wk. Genetic differences for LM, BM, and LM/BM were found among the base sire lines and between two-way crosses. Heritabilities and genetic correlations for LM, BM, LM/BM, and LM/MBM (MBM = …
Exogenous Progesterone And Progestins As Used In Estrous Synchrony Regimens Do Not Mimic The Corpus Luteum In Regulation Of Luteinizing Hormone And 17Β-Estradiol In Circulation Of Cows, N. Kojima, T. T. Stumpf, Andrea S. Cupp, L. A. Werth, M. S. Roberson, M. W. Wolfe, Roger J. Kittok, James E. Kinder
Exogenous Progesterone And Progestins As Used In Estrous Synchrony Regimens Do Not Mimic The Corpus Luteum In Regulation Of Luteinizing Hormone And 17Β-Estradiol In Circulation Of Cows, N. Kojima, T. T. Stumpf, Andrea S. Cupp, L. A. Werth, M. S. Roberson, M. W. Wolfe, Roger J. Kittok, James E. Kinder
Department of Animal Science: Faculty Publications
Our working hypothesis was that the low concentrations of progesterone (P4) and synthetic progestins administered in hormonal regimens to control estrous cycles of cows would have similar effects on secretion of LH and 17β-estradiol (E2). In addition, we hypothesized that concentrations of exogenous P4 typical of the midluteal phase of the estrous cycle and the corpus luteum (CL) would have similar effects on LH and E2, and the effects would be different from those of synthetic progestins and low concentrations of P4. Cows (n = 29) were randomly assigned to one …
Steady-State Amounts Of Α- And Luteinizing Hormone (Lh) Β-Subunit Messenger Ribonucleic Acids Are Uncoupled From Pulsatility Of Lh Secretion During Sexual Maturation Of The Heifer, M. S. Roberson, M. W. Wolfe, T. T. Stumpf, D. L. Hamernik, Andrea S. Cupp, L. A. Werth, N. Kojima, Roger J. Kittok, H. E. Grotjan, J. E. Kinder Kinder.15@Osu.Edu
Steady-State Amounts Of Α- And Luteinizing Hormone (Lh) Β-Subunit Messenger Ribonucleic Acids Are Uncoupled From Pulsatility Of Lh Secretion During Sexual Maturation Of The Heifer, M. S. Roberson, M. W. Wolfe, T. T. Stumpf, D. L. Hamernik, Andrea S. Cupp, L. A. Werth, N. Kojima, Roger J. Kittok, H. E. Grotjan, J. E. Kinder Kinder.15@Osu.Edu
Department of Animal Science: Faculty Publications
Our primary objective for this study was to determine whether steady-state amounts of α - and LH β-subunit mRNAs in the anterior pituitary are altered during sexual maturation in the bovine female. A secondary objective was to determine whether 17β-estradiol (E2) alters amounts of LH subunit mRNAs before onset of puberty. Heifers (7 mo old) were assigned to one of three treatments: 1) ovariectomized (OVX, n = 16); 2) OVX and administered E2 (OVXE, n = 16); or 3) ovary-intact (INTACT, n = 20). Pituitaries were collected at an estimated 120 days before onset of puberty (prepuberty) …
Response Time Of Broiler Chickens To Cimaterol: Meat Tenderness, Muscle Composition, Fiber Size, And Carcass Characteristic, B. L. Gwartney, Steven J. Jones, Chris R. Calkins
Response Time Of Broiler Chickens To Cimaterol: Meat Tenderness, Muscle Composition, Fiber Size, And Carcass Characteristic, B. L. Gwartney, Steven J. Jones, Chris R. Calkins
Department of Animal Science: Faculty Publications
The response time to cimaterol (CIM), a P-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At …
Multiple-Trait Restricted Maximum Likelihood For Simulated Measures Of Ovulation Rate With Underlying Multivariate Normal Distributions, L. Dale Van Vleck, K. E. Gregory
Multiple-Trait Restricted Maximum Likelihood For Simulated Measures Of Ovulation Rate With Underlying Multivariate Normal Distributions, L. Dale Van Vleck, K. E. Gregory
Department of Animal Science: Faculty Publications
A data set that was used to estimate covariance components with REML for an animal model with eight measures of ovulation rate treated as separate traits was used as a template to simulate data sets of eight multivariate normal traits that were then truncated to binomial traits. The model for simulation included eight measures on 610 animals with 1,071 animals in the numerator relationship matrix. Heritabilities were equal for the eight measures, and both genetic and phenotypic correlations among the measures were equal. Ten replications for each combination of heritability (.15, .25, and .35) and genetic correlation (.50, .66 and …
Circulating Gonadotrophins During A Period Of Restricted Energy Intake In Relation To Body Condition In Heifers, M. S. Roberson, T. T. Stumpf, M. W. Wolfe, Andrea S. Cupp, N. Kojima, L. A. Werth, Roger J. Kittok, J. E. Kinder
Circulating Gonadotrophins During A Period Of Restricted Energy Intake In Relation To Body Condition In Heifers, M. S. Roberson, T. T. Stumpf, M. W. Wolfe, Andrea S. Cupp, N. Kojima, L. A. Werth, Roger J. Kittok, J. E. Kinder
Department of Animal Science: Faculty Publications
Beef heifers, 13 months old, were fed to achieve high (7·6 + 0·2 units) or low (3·9 ± 0·1 units) body condition by feeding them one of two diets for 20 weeks. During week 17 of the growth phase, all heifers were ovariectomized. From week 20 to week 27 (restriction phase), all heifers were fed a daily diet containing 0·071 MJ metabolizable energy kg-1 body weight. At weekly intervals throughout the restriction phase, blood samples were collected at 10-min intervals for 11 h to determine the pattern of secretion of luteinizing hormone (LH), the amount of LH released in …
Similar Distribution Of Gonadotropin Isohormones Is Maintained In The Pituitary Throughout Sexual Maturation In The Heifer, T. T. Stumpf, M. S. Roberson, M. W. Wolfe, D. D. Zalesky, Andrea S. Cupp, L. A. Werth, N. Kojima, K. Hejl, Roger J. Kittok, H. E. Grotjan, J. E. Kinder
Similar Distribution Of Gonadotropin Isohormones Is Maintained In The Pituitary Throughout Sexual Maturation In The Heifer, T. T. Stumpf, M. S. Roberson, M. W. Wolfe, D. D. Zalesky, Andrea S. Cupp, L. A. Werth, N. Kojima, K. Hejl, Roger J. Kittok, H. E. Grotjan, J. E. Kinder
Department of Animal Science: Faculty Publications
Our working hypotheses for this study were that 1) the profile of intrapituitary LH and FSH isoforms would be shifted toward acidic forms as sexual maturation progresses in the bovine female; and 2) concentration of 17β-estradiol (E2) in circulation during sexual maturation would be a major factor modulating the percentage of the more acidic isoforms. In addition, the biological: immunoreactive (B:l) ratios of each isoform of LH were evaluated at selected stages of sexual maturation. Heifers (7 mo of age) were assigned to one of three treatment groups: 1) ovariectomized (OVX; n = 16); 2) OVX and administered …