Biomedical subjects

W E Vinson

Publications and source records attributed to W E Vinson.

At least 19 recordsLinked to original sources

PubMed1991

Effect of gestational mastectomy on postpartum gonadotropin releasing hormone and thyrotropin releasing hormone-induced luteinizing hormone and prolactin response in first lactation Holstein cattle.

First lactation Holstein cows were divided into two treatment groups to evaluate thyrotropin releasing hormone (TRH, 0.25 microgram/kg body weight) and gonadotropin releasing hormone (GnRH; 200 micrograms) induced secretion of prolactin (PRL) and luteinizing hormone (LH) on days 7 and 16 postpartum. Disregarding treatment, LH response was greater (p less than 0.01) on day 16 than day 7 postpartum (7.5 +/- 0.3 ng/ml on day 7 vs 10.2 +/- 0.3 ng/ml serum on day 16). Mastectomized cattle had similar time for initiation of LH increase, but peak concentrations were achieved later. Peak PRL concentrations were reached 12 to 15 min after injection and returned to baseline within 2.5 h in both groups. However, intact cows had higher (p less than 0.01) mean serum PRL than the mastectomized cows for 1 h following injection. Peak PRL concentration was 83.3 +/- 17.6 ng/ml for mastectomized cows vs 128.0 +/- 24.7 ng/ml for intact cows. It appears that udder removal allows for greater pituitary responsiveness to GnRH but diminishes PRL response to TRH suggesting the mammary gland differentially affects pituitary secretion of LH and PRL.

Animals↗

PubMed1989

Early postpartum reproductive profiles in Holstein cows with retained placenta and uterine discharges.

Sixty Holstein cows were allocated to three groups. Twenty cows had retained placenta. The remaining cows were examined on d 14 postpartum and those with purulent discharges (n = 22) were assigned to one group and the remaining (n = 18) to a control group. Within each group, cows were given randomly either gonadotropin-releasing hormone (i.m., 200 micrograms) or saline on d 15 postpartum to evaluate the effect on changes in ovarian structures and plasma progesterone through 50 d postpartum and fertility. Corpora lutea were found in control cows by d 21, cows with uterine discharge by d 28, and cows with retained placenta by d 27. Maximum progesterone production during the first luteal phase was higher in control cows than in cows with purulent discharge or retained placenta (4.66 ng/ml compared with 3.23 and 3.34 ng/ml, respectively). Duration of the first corpus luteum was affected by clinical condition. Only 6.2% of cows with retained placenta had corpora lutea of normal duration (12 to 16 d), whereas 43.8 and 50.0% of cows with uterine discharge and control cows had normal postpartum luteal phases. Measures of fertility were not affected by gonadotropin-releasing hormone. Control cows had less days to conception (97) and fewer services per conception (1.6) than cows with retained placenta (134 and 2.5, respectively). Clinical group affected reproduction more than gonadotropin-releasing hormone did, possibly by altering ovarian function.

Animals↗

PubMed1988

Influence of uterine flushings from superovulated cows on in vitro bovine morulae development.

To evaluate early embryo development, 248 good to excellent bovine morulae were cultured in Ham's F-10 medium, supplemented with 10% steer serum, uterine flushings from Days 6, 10 or 15 following estrus (0.01, 0.1, 1.0 and 10% protein; 64 mg protein/ml), and 1.0% uterine flushings and 10% steer serum. Final development scores for embryos in steer serum were significantly higher (range across experiments was: 4.06 to 4.37) than for embryos cultured in uterine flushings alone (-0.23 to 0.52). Treatment means were not different (P >0.05) when 10% steer serum was added to 1.0% uterine flushings. A higher percentage of embryos in 10% steer serum (92%) than in 10% steer serum plus 1.0% uterine flushing from Day 6 (33%), Day 10 (45%) and Day 15 (50%) developed to hatched blastocysts. Embryos cultured in 1.0% Day 6 uterine flushings plus 10% steer serum required more time to attain the early blastocyst and blastocyst stages, while embryos in 1.0% Day 15 uterine flushings and 10% steer serum developed at the same rate as controls to the expanded blastocyst stage, but hatched sooner (72.8 vs 96.5 h). These results suggest substance(s) in uterine secretions can have inhibitory and stimulatory influences on early bovine embryo development.

Journal Article↗

PubMed1988

Culture of bovine morulae in media supplemented with immunoglobulins.

Bovine morulae (d 6; n = 257) were obtained to evaluate the effect of Ig on embryo development in vitro to the hatched blastocyst stage or until degeneration. Embryos were cultured in Ham's F-10 containing either 6.4 mg/ml steer serum, .64 mg/ml bovine gamma globulins, bovine IgG, bovine IgM alone, and steer serum added to gamma globulins, IgG, or IgM. In steer serum alone, 69.6% of the embryos developed to the expanded blastocyst stage, whereas 73.9% of embryos in gamma globulin and steer serum and 25% of embryos in gamma globulin alone reached the same stage of development. None of the morulae cultured in IgG and IgM alone or IgG and IgM with steer serum reached the expanded blastocyst stage. Additionally, the times to degeneration were shorter when embryos were cultured in IgG (54.9 h) and IgM (59.4 h) plus steer serum than for embryos placed in gamma globulin plus steer serum (77.6 h) or steer serum (81.5 h) alone. These results suggest that .64 mg/ml bovine gamma globulin did not affect embryo growth, whereas .64 mg/ml IgG and IgM were toxic to early development of bovine embryos in vitro.

Animals↗

PubMed1987

Effect of low dose of FSH given at the beginning of the estrous cycle and subsequent superovulatory response in Holstein cows.

A total of 47 superovulations were conducted on forty non-lactating cows to evaluate two different schemes using follicle stimulating hormone (FSH) for superovulating cattle. Cows randomly assigned to treatment A (26 collections) were superovulated beginning on days 9 to 13 of the estrous cycle by giving FSH at decreasing doses of 6, 6, 5, 5, 3, 3, and 2, 2 mg for 4 consecutive days at 12-h intervals while those in treatment B (21 collections) also received 2.5 mg of FSH on days 3 and 4 of the estrous cycle. Animals in both treatments were each given 12.5 mg of prostaglandin F2alpha (PGF2alpha) at 60 and 72 h after the initiation of superovulatory treatment. Cows were artificially inseminated at 0, 12, and 24 h after the onset of estrus. Embryos were recovered nonsurgically on d 6 and morphologically evaluated. Ovaries of the cows were palpated at the end of flushings to assess the number of corpora lutea (CL). The mean interval from PGF2alpha to the onset of estrus was not different (P>0.05) for treatments A (56.6 h) and B (50.0 h). Also, mean duration of standing estrus was not different for either treatment (13.4 h vs 12.8 h). The mean number of CL palpated (7.3 vs 12.9) and ova recovered (5.5 vs 14.2) were significantly greater (P<0.05) for treatment B. The mean number of excellent and good embryos recovered was lower for treatment A animals, but not significant (P>0.05). Therefore, low doses of FSH given at the beginning of the cycle increased ovulation rate and embryo recovery in non-lactating cows.

Journal Article↗

PubMed1987

Potential bias in genetic evaluations from differences in variation within herds.

Evidence is reviewed that indicates substantial differences among herds in variation for production traits in dairy cattle. Examples are given to illustrate the overevaluation and selection of higher proportions of individuals from more variable herds, which reduces response to selection if greater variability is not due in part to greater additive genetic variance. Differences in heritability according to herd mean and variance are examined. Potential bias is substantial in genetic evaluations of cows and may increase over generations where, if the model is realistic, evaluations of dams are used in evaluations of daughters. Possible methods of adjustment are discussed.

Animals↗

PubMed1986

In vitro development of bovine morulae in bovine serum albumin, normal steer serum and uterine flushings.

One hundred fifty-three excellent and good bovine morulae were cultured in Ham's F-10, supplemented with 10 % steer serum, bovine serum albumin, or uterine flushings (64 mg protein/ml) to compare embryo development. Embryos were observed every 12 h in culture. Treatment differences were evaluated by assigning a numerical value of 0 to 4 to each embryo representing the stage of development reached in vitro. The final morphological developmental score of the embryos was comparable for steer serum (2.66) and bovine serum albumin (2.50), but it differed significantly for uterine flushings obtained from ovariectomized, steroid-supplemented cows (< 0.1) or heat-treated uterine flushings (0.07). Since albumin alone was able to support development, it suggests that the albumin component of steer serum may be responsible for the observed development. Uterine fluids were unable to support growth of embryos, suggesting that incompatibility may be due to asynchrony between the early bovine embryo and uterine constituents, or a concentration of uterine components may exacerbate actions of inhibitory substances.

Journal Article↗

PubMed1986

Effect of endothelial cell growth supplement and fibroblastic growth factor on early mouse embryo development in vitro.

This study was conducted to examine the effect of endothelial cell growth supplement (ECGS) and fibroblastic growth factor (FGF) on early mammalian embryo development in vitro. Two hundred mouse blastocysts were placed randomly in culture wells containing one of five treatments: 1) Ham's F-10, 2) Ham's F-10 + 10 mug ECGS, 3) Ham's F-10 + 10 ng ECGS, 4) Ham's F-10 + 100 ng FGF and 5) Ham's F-10 + 10 ng FGF. In all cases, media were supplemented with 10% (v/v) normal steer serum. Embryos were cultured at 37 C with an atmosphere of 5% O(2), 5% CO(2) and 90% N and development was recorded at 12 h intervals for the duration of culture. The percentage of embryos that developed to expanded blastocyst (94.8), hatching blastocyst (74.4) and hatched blastocyst (71.8) in Ham's F-10 media were not different from embryos cultured in all other treatments except Ham's F-10 + 10 mug ECGS. A decrease in the percentage of embryos reaching expanded blastocyst (44.7), hatching blastocyst (23.7) and hatched blastocyst (18.4) was observed in Ham's F-10 + 10 mug ECGS. Also, a significant (P<0.01) decrease in development scores at 24, 48 and 72 h was observed for embryos cultured in Ham's F-10 + 10 mug ECGS. No difference was observed in the mean time to reach different developmental stages among treatments. The data suggest that ECGS and FGF at the doses tested have no beneficial effect on early mouse embryo development in vitro and 10 mug of ECGS has inhibitory effect.

Journal Article↗

PubMed1986

Somatic cell counts and infection rates for cows of varying somatic cell count in initial test of first lactation.

Somatic cell counts (log, base 2) and rates of infection in first and subsequent lactations were examined by classes of somatic cell count in initial test day of first lactation to determine if cows with initially low counts were more at risk to subsequent mastitis infection. Classes of initial somatic cell counts were less than 100,000, 100,000 to 400,000 and greater than 400,000. Differences among initial classes in subsequent cell counts were small, but the initial rank of classes was maintained throughout the remainder of first lactations and in subsequent lactations. Differences among initial classes for rates of infection in first and subsequent lactations consistently favored low initial cell counts. Results gave no indication that cows initially low in cell count are at greater risk of subsequent mastitis infection.

Animals↗

PubMed1986

Use of laboratory mice to study genetic relationships among milk yield and number of somatic cells.

Preliminary results of bidirectional selection for increased and decreased somatic cell counts in milk of laboratory mice were used to assess the usefulness of the laboratory mouse as a pilot organism for the study of yield and somatic cell count relationships in dairy cattle. Procedures developed permit relatively rapid and accurate determination of somatic cell counts in milk of mice. Concentration of somatic cells was three to four times greater in mice than in dairy cows, but counts were distributed similarly. A large effect for stage of lactation existed with high counts in late lactation. Within lactation, repeatability of somatic cell counts and relationships between somatic cell counts and milk yield were similar to those reported for dairy cattle. Heritability of lactation average somatic cell count (3 sample d, log base 2, adjusted for stage of lactation) was .24, indicating lines genetically divergent for somatic cell count can be developed.

Animals↗

PubMed1986

Potential of somatic cell concentration in milk as a sire selection criterion to reduce mastitis in dairy cattle.

Lactation records for somatic cell counts in milk, bacteriological culture results, antibiotic treatment for mastitis, and production were formed for cows in 30 cooperating dairy herds in Virginia. A second data set, including somatic cell counts and production information for cows in approximately 400 herds in Virginia (not including the original 30), was used to evaluate sires genetically for somatic cell count. Approximate genetic correlations between measures of cell count and measures of infection ranged from .36 to .67. These were highest (lowest) for frequency of infection by major (minor) pathogens. Corresponding phenotypic correlations were similar but slightly smaller. Neither somatic cell counts nor measures of infection were well correlated with treatment. Production traits generally had small, negative genetic and phenotypic relationships with cell counts, rates of infection, and measures of treatment. Correlations for evaluations of sires for cell count were positive with daughter averages for infection rates (.20 to .38) and treatment measures (.02 to .13). Largest (absolute value) correlations between evaluations of sires for cell count and production traits were for fat percentage (-.38) and fat yield (-.28). Evaluation and selection of sires for decreased somatic cell count may augment management and treatment programs in the reduction of mastitis incidence.

Animals↗

PubMed1986

External factors that affect grades in graduate physiology.

Data from 251 students over 11 yr were used to evaluate factors affecting the final grade in a graduate animal anatomy and physiology course. Background information obtained on the first class day included major, major professor, degree(s) and location(s) of matriculation, and participation in science courses. A pretest was administered to identify each student's background. Final numerical grade was influenced by major, degree, College where bachelor's degree was obtained, and gender. Students from fisheries and wildlife had higher final numerical grade than other majors. Undergraduates scored lower than master's or doctoral students. Students from small colleges and foreign institutions obtained lower final numerical grades than students from agricultural universities and major colleges. Females had higher final grades (81.3 +/- 1.7) than males (79.6 +/- 1.7). Pretest score was indicative of final grade and was affected by degree, college of bachelor's degree, year, and organic chemistry. Master's students had pretest scores 6.1 higher than bachelor's students; students with organic chemistry scored higher than students with none, and foreign students score lowest of all groups by college of bachelor's degree. Change in score from pretest to final grade was affected by major, degree, gender, and pretest score. The student's background in biochemistry, cell physiology, and organic chemistry and motivation can affect success in graduate physiology and anatomy.

Anatomy↗

PubMed1985

Observations on in vitro development of bovine morulae in Ham's F-10 and Dulbecco's phosphate buffered saline supplemented with normal steer serum.

This study was conducted to compare in vitro development of bovine morulae in Ham's F-10 and Dulbecco's phosphate buffered saline (D-PBS) media supplemented with 10% (v/v) normal steer serum. Fifty-three excellent and good embryos were obtained by superovulating 15 non-lactating Holstein cows. Embryos were placed randomly in culture with Ham's F-10 or D-PBS media and development was recorded at 12-h intervals for the duration of culture. All embryos reached early blastocyst, blastocyst and expanded blastocyst stage. Nineteen of 27 embryos (70.1%) cultured in Ham's F-10 developed to hatched blastocyst stage in contrast to three out of 26 in D-PBS (11.5%). The mean developmental scores at 24, 48, 72, 96 and 120 h of culture were significantly (P<0.001) higher for embryos cultured in Ham's F-10. Also, the mean times to reach early blastocyst (25.84 +/- 6.65 vs 46.67 +/- 9.99 h), blastocyst (44.57 +/- 11.45 vs 61.89 +/- 16.62 h) and expanded blastocyst stage (65.00 +/- 13.20 vs 73.41 +/- 15.80 h) were significantly (P<0.001) shorter for embryos cultured in Ham's F-10. No difference was observed in the mean time to reach hatching (90.00 +/- 10.85 vs 84.00 +/- 16.97 h) and hatched blastocyst stage (97.26 +/- 18.71 vs 96.00 +/- 0.00 h). The results obtained support the concept that Ham's F-10 and normal steer serum provide for optimal bovine embryo development and suggest that 10% normal steer serum could be used as a protein supplement with D-PBS for short term storage and culture of bovine embryos.

Journal Article↗

PubMed1985

Genetic and phenotypic relationships among type traits scored linearly in Holsteins.

Phenotypic and genetic parameters were estimated for 12 type traits of Holstein cows scored linearly by personnel of an artificial insemination organization. Estimates were compared with those from programs offered by the breed association and by two other artificial insemination organizations. All programs were based on scoring guidelines of the National Association of Animal Breeders. Heritabilities of linear type traits ranged from .40 for stature to .14 for fore udder attachment with heritabilities for udder traits smaller than for nonudder traits. Largest genetic and phenotypic correlations were among udder traits with genetic correlations consistently exceeding phenotypic correlations. Similarities in relative magnitudes of phenotypic and genetic parameters suggest that linear type appraisal programs do not differ greatly among organizations using scoring guidelines of the National Association of Animal Breeders.

Animals↗

PubMed1985

Components of genetic variance and covariance for linear type traits in Jersey cattle.

First available appraisals for 67,644 Jersey cows were used to estimate relative magnitudes of additive and selected sources of nonadditive genetic variance and covariance for 13 type traits scored linearly from 50 to 99 points. Covariances among four types of relatives were used to estimate components of genetic variance and covariance for each of the 13 traits. Direct additive, direct dominance, and additive maternal genetic variances and the direct-maternal additive genetic covariance were estimated using covariances among paternal half-sibs, full-sibs, daughters and dams, and maternal half-sibs. Estimates of additive genetic variance were 11 to 36% of variance within herd-appraiser subclasses with largest values for stature, strength, rump angle, rump width, and udder depth. Dominance components were two to four times the magnitude of additive components for dairy character, rump width, fore udder, rear udder height, rear udder width, and suspensory ligament but much smaller for other traits. Maternal effects and the direct-maternal additive genetic covariance appeared small for all linear type traits.

Animals↗

PubMed1984

Relationships between linear type scores, objective type measures, and indicators of mastitis.

Objectives were to examine the usefulness of objective measures of conformation and linear scores for type for predicting indicators of mastitis. Approximately 300 cows in five herds were scored in the experimental linear classification program of the Holstein-Friesian Association of America, measured objectively for numerous components of conformation, and evaluated for four indicators of mastitis. Indicators of mastitis were average natural logarithm of somatic cell counts during the lactation, percent of samples (taken approximately every 3 mo) infected during a lactation, percent of samples infected with Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, Klebsiella, and percent of samples with signs of mastitic milk. Relationships between conformation and mastitis often were inconsistent because of moderate or low correlations between indicators of mastitis. Indicators of mastitis were predicted from results of multiple regression analyses with subjective scores and objective measures of type as independent variables. Largest differences of predicted indicators of mastitis from variation in any single type trait were sufficient to be important economically, but average differences were much smaller. Selection to reduce frequencies of cows with deep udders, especially low rear udders, widely placed teats, rear teats too far back, and teats that are short and wide, may augment, modestly, efforts to reduce incidence of mastitis through improved sanitation, antibiotic treatment, and proper milking procedures.

Animals↗

PubMed1983

Pedigree information to predict genetic merit for type of Holstein bulls.

Three methods of computing predicted differences for type were compared for accuracy of pedigree evaluation of young Holstein bulls. Computing methods were herdmate comparison, herdmate comparison adjusted for genetic merit of herdmates, and best linear unbiased prediction. Evaluations by progeny test were available for 1298, 1293, and 1088 sons and sires for herdmate comparison, herdmate comparison adjusted for cow index of herdmates, and best linear unbiased prediction with fewer sons having more complete pedigrees. Ten regression models were used to predict eventual progeny test evaluations of sons from combinations of evaluations for sires, dams, and maternal grandsires. Negative intercepts and smaller than expected regression coefficients suggested bias in evaluations by all methods but much less bias with best linear unbiased prediction than with other methods. Multiple correlations generally were largest for equations using evaluations by best linear unbiased prediction.

Animals↗

PubMed1982

Response to selection for milk yield in Holsteins.

Data were collected for 11 yr in five institutional herds in Virginia to determine the response to selection for milk yield and to examine correlated response in other traits. A randombred control population allowed separation of genetic and environmental effects. The genetic base was the same for both control and selection groups, and little directional selection took place in the control population. The control line was generated from 12 sire lines initiated by 8 unproven sires sampled by artificial insemination and sons of 4 proven bulls. Four bulls high for Predicted Difference milk were used in the selection group each year. By three methods of analysis, best linear unbiased prediction, deviation of selection from control group means, and least squares differences between selection and control for milk, fat, and fat percentage were: 370, 374, 438 kg; 10, 8, 6 kg; and -.02, -.02, and -.10%. These agree closely with expectations from modified contemporary comparisons of the bulls. Differences in fat percentages were more variable although all analyses indicated a negative correlated response to selection for milk yield. Generation effects varied with method of analysis but were generally small and agreed with differences in sire Predicted Differences. Response differed across herds.

Animals↗