Biomedical subjects

R W Adkinson

Publications and source records attributed to R W Adkinson.

32 records · Page 2Linked to original sources

PubMed1989

An efficient procedure for manual platelet counting.

Blood samples were collected by jugular venipuncture from 15 dairy heifers and the blood platelets were counted by manual methods. The platelets were found to be uniformly distributed across the rows, columns and sides of a Neubauer haemocytometer, and it was shown that counting any 10 squares on either side of the haemocytometer and multiplying by a constant factor would accurately predict the total platelet count. This procedure would greatly reduce the time required to count large numbers of platelets per sample, and reduce errors due to the fatigue associated with counting large numbers of samples.

Animals↗

PubMed1989

Effect of feeding gossypol in cottonseed meal on growth, semen quality, and spermatogenesis of yearling Holstein bulls.

Yearling Holstein bulls were fed a corn silage ration supplemented with either cottonseed meal with gossypol or soybean meal in two trials to evaluate the effect of feeding gossypol on reproductive characteristics. In Trial 1, roughage to concentrate ratio was 88:12 and was fed for 60 d. In Trial 2, roughage to concentrate ratio was 50:50 and was fed for 42 d. Cottonseed meal concentrate had 3.03 g total gossypol/kg DM. Cottonseed meal concentrate was fed to provide 6 and 30 mg total gossypol/kg BW per d in Trials 1 and 2. Ejaculates were collected twice weekly via artificial vagina and critiqued for quantity and quality before and after thawing and after postthaw incubation. Leptotene spermatocytes to Sertoli cell ratio in stage 1 tubules was used to evaluate spermatogenesis. Growth characteristics and tissue total gossypol concentrations were also evaluated. No gossypol was found in plasma taken before, during, or after Trial 1 or from body organs or plasma taken during or after Trial 2. No signs of gossypol toxicity were observed, and growth characteristics were similar on both rations. Gossypol in cottonseed meal fed at low to moderate concentrations was not deleterious to seminal quantity or quality, and spermatogenesis was unaffected by treatment.

Animal Feed↗

PubMed1988

Effect of disc moistening method on Bacillus stearothermophilus disc assay zone diameters.

Effect of disc moistening method on the Bacillus stearothermophilus disc assay zone size was studied. Pasteurized homogenized milk was subdivided and three levels of US Pharmacopeial reference standard penicillin G were added. Disc assay filter paper discs were moistened using the standard capillary action procedure and a method incorporating the use of a 90-microliters micropipetter. Amount of milk sample absorbed by discs prepared by the capillary action method was correlated with disc mass. Variation in amount of milk absorbed by discs was significantly greater when discs were prepared by capillary action. Zone diameter means and standard errors across all penicillin G concentrations tested were not significantly different for the two methods. The 90-microliters micropipetter method is recommended as an alternative to the capillary action method.

Animals↗

PubMed1987

Use of linear semen quality score for classification and decision making in evaluation of individual ejaculates of Holstein bulls.

Four hundred seven ejaculates from 15 Holstein bulls collected from December 1984 to June 1985 were evaluated postthaw for viability characteristics (percent progressive motility at 0 h and after 3 h at 37 degrees C incubation, percent intact acrosomal membrane after 3 h at 37 degrees C incubation) and abnormal morphological characteristics [percent head (primary), midpiece, and tail (secondary) abnormalities]. Weighting coefficients for combining viability and abnormality characteristics were generated from between-bull and within-bull variance and covariance matrices. Two hundred ninety-eight additional ejaculates collected from July 1985 to February 1986 were added. Linear quality scores for 705 ejaculates (24 bulls) were the sum of the product of each quality characteristic and weighting coefficients. Univariate analysis yielded significant bull effects for viability and abnormality characteristics and linear quality score. Significant correlations existed between all seminal quality characteristics except primary and secondary abnormalities. A t test with preassigned critical value was used to evaluate each ejaculate to determine rejection from the population. Percent of ejaculates rejected was lower when linear quality score was used than when five independent tests were used. Use of linear quality score to critique semen based on each ejaculate's innate quality could compensate for the loss of bull fertility estimates from declining number of technician-based AI programs.

Animals↗

PubMed1987

Effect of plate preincubation on Bacillus stearothermophilus disc assay zone diameters.

Effect of plate preincubation on the Bacillus stearothermophilus disc assay zone size was studied. Each of three raw milk samples were subdivided and treated with five levels of US Pharmacopeial reference standard penicillin G. Freshly prepared, 2.5- and 5-d old seeded disc assay culture plates were preincubated at 64 degrees C for 0 (control), 20, 40, 60, 80, 100, and 120 min prior to placement of discs on the medium surface. Plate age did not have a significant effect on the size of the zone diameter. Following 20 and 40 min of plate preincubation, zone diameters were in some, but not all, cases significantly different from the control. Plate preincubation of 60 min or greater always significantly decreased zone diameter. Routine preincubation of B. stearothermophilus plates is not recommended. In situations where time is a critical factor, plates should be preincubated no longer than 40 min.

Animals↗

PubMed1986

Effect of serum sources and colostral whey on bovine semen quality and spermatozoa immunoglobulin G immunofluorescence.

Heifer, bull, fetal calf sera, and colostral whey were used to evaluate the influence of protein concentrations on percent progressive motility, head-to-head agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence of bovine spermatozoa using ejaculates from 10 bulls. In the first experiment, 10% (vol/vol) addition of undiluted colostral whey resulted in the highest head-to-head agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence. Ten percent (vol/vol) addition of whey diluted to a protein concentration equivalent to fetal calf serum produced significantly lower agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence. Fetal calf serum was unable to produce agglutination and immunoglobulin G immunofluorescence of bovine spermatozoa. Heifer and bull sera produced similar responses for all seminal measurements. In Experiment 2, unheated whey and heifer serum resulted in higher response for all variables than heat inactivated whey and heifer serum. Whey treatment produced greater spermatozoal motility, agglutination, acrosomal integrity; and immunoglobulin G immunofluorescence than treatment with heifer serum. Spermatozoal immunofluorescence indicated antibodies in normal whey, bull, and heifer serum bound to spermatozoal membranes at the acrosomal region. Colostral whey was an effective source of agglutinin factor. Normal unheated whey and heifer serum did not cause sperm damage or immobilization.

Animals↗

PubMed1985

Environmental and genetic sources of variation for seminal quality in mature Holstein bulls.

Various environmental and genetic factors that influence seminal quality were evaluated for 149 Holstein bulls used extensively in nine artificial insemination organizations (studs). These bulls were sons of 16 sires. Seminal quality was measured by percent progressive motility immediately postthaw and after incubation at 3 h, 37 degrees C, percent intact acrosomal membrane after incubation at 3 h 37 degrees C, and percent primary and secondary abnormalities. Semen was thawed at 37 and 24 degrees C. Spermatozoal concentration was counted with a hemocytometer. Bull age and season of collection were determined. Interaction of stud X thaw existed for both motility assessments and intact acrosomes, but 37 degrees C thaw resulted in higher motility and acrosomal integrity across all studs. Motility at zero hour was affected by season. Secondary abnormalities were influenced by season and stud X season. Interaction of thaw X season existed for incubated motility, which also was influenced by concentration and age. Age influenced secondary abnormalities. Heritabilities and repeatabilities (%) were .21, 44; .40, 34; .81, 74; and .31, 50 for 0-h motility, intact acrosomes, primary abnormalities, and secondary abnormalities. Genetic correlations were 0-h motility with acrosomal integrity and primary and secondary abnormalities, .88, -.70, -.93; acrosomal integrity with primary and secondary abnormalities, -.90, -.05; primary with secondary abnormalities, -.12. Selection for semen quality could improve fertility of bulls.

Acrosome↗

PubMed1984

Thawing optimums for bovine spermatozoa processed by three methods and packaged in Continental and French straws.

A modified two-dimensional central composite rotatable design was used to study the effect of thaw bath temperature and time on acrosomal integrity in Continental (.3 ml) and French (.5 ml) straws. Ejaculates from 18 bulls were packaged in both containers. Semen from 6 of the 18 bulls was processed by each of three methods: 6 bulls for egg yolk-Tris-glycerol, 6 bulls for egg yolk-citrate-glycerol, and 6 bulls for skim milk-glycerol. Thaw bath temperatures ranged from 18 to 92 degrees C, and thaw times ranged from 4.5 to 50 s. Interaction of thaw bath temperature with thaw time was detected within each processing procedure and package. Maximum cell quality, measured by intact acrosomes after incubation of semen 3 h at 37 degrees C for .3-ml and .5-ml straws, was predicted to be achieved by thaw bath temperatures and times (degrees C/s) as follow: egg yolk-Tris-glycerol 40/32, 49/16; egg yolk-citrate-glycerol 43/30, 37/19; skim milk-glycerol 50/24, 36/24. Thawing procedures to maintain best acrosomal retention, regardless of processing method, were 44 degrees C for 29 s for .3-ml straws and 40 degrees C for 20 s for .5-ml straws.

Acrosome↗

PubMed1984

Relationship between final temperature, thaw rate, and quality of bovine semen.

Relationships between thaw rate, thaw bath time, and initial bath and final seminal temperature with coefficients of determination .99 and .97 were: bath time = -.01 + 220.25(1/thaw rate); initial bath temperature = final seminal temperature - 7.29 + 390.05 (1/bath time). Ejaculates from 10 bulls were split and processed in egg yolk-citrate-glycerol, egg yolk-Tris-glycerol, and whole milk-glycerol. All semen was packaged and frozen in .5-ml French straws at -196 degrees C. Sixteen thaw treatments consisted of factorial combinations of four final seminal temperatures and four thaw rates. Treatments were assessed by post-thaw acrosomal integrity after 3-h 37 degrees C incubation. Seminal quality improved with increasing final seminal temperature up to 31 degrees C and did not differ between 31 and 44 degrees C for any of the extenders. A slow thaw rate (3 degrees C/s) resulted in inferior quality for all extenders, and rates 11, 19, and 27 degrees C/s resulted in similar quality for citrate and milk extended semen. Acrosomal integrity was most for 19 degrees C/s in Tris extended semen. A significant factorial interaction existed for Tris and milk extended semen. Predicted acrosomal response of 57.7% across all extenders was at optimum final seminal temperature and thaw rate 37 degrees C and 18 degrees C/s. Bath temperature and bath time determine optimum thaw rate and final temperature of semen packaged in French straws and thus maximize seminal quality.

Acrosome↗

PubMed1983

Optimum thawing temperature and time for bovine semen processed by three methods and packaged in 1 ml ampules.

A central composite rotatable design was used to determine optimum temperature and time for thawing semen which was processed in egg yolk-tris-glycerol (ETG), egg yolk-citrate-glycerol (ECG) and skim milk-glycerol (SMG) diluents. Percentage of progressive motility (PPM) and percentage of intact acrosomes (PIA) immediately after thawing (0-hr) and after 3-hr incubation at 37 degrees C were measured. The optimum conditions for temperature and time (C/sec) to sustain maximal PIA response after 3-hr incubation (PIA) were: ETG 42 degrees 121 , ECG 33 degrees 175 , and SMG 38 degrees 128 . Average conditions predicted to be "shared" by all three processing methods were 35 degrees C for 150 sec. Final seminal temperature (FST) was measured at each of these points for ETG, ECG and SMG. Each of the above conditions has a FST above 30 degrees C. A strip plot design was used to compare the optimum and predicted "shared" (35 degrees C 150 sec ) conditions with recommended method (35 degrees C 65 sec ) presently in use, denoted as "present". The predicted "shared" thawing conditions resulted in greater (P<0.01) cell viability (PPM and PIA) than did the "present" thawing method both before and after 3-hr incubation. The viability of semen thawed by the predicted "shared" method did not differ (P<0.05) from that resulting from the optimum thawing condition for each processing method (ETG, ECG and SMG) at 0-hr or 3-hr incubation. Cell viability of skim milk-glycerol processed semen degraded faster over the 3-hr incubation period that did that of ETG or ECG processed semen.

Journal Article↗

PubMed1982

Effects of vacuum and pulsation ratio on udder health.

Effects of vacuum and pulsation ratio on udder health were studied for 36 first parity animals in a 60-day trial. Treatments consisted of vacuum at 33.3, 41.6, and 50 kPa at pulsation ratios of 50:50, 60:40, and 70:30 at 60 pulsations per min. All teats were exposed to a culture broth of Staphylococcus aureus after machine removal. Numbers of intramammary infections and somatic cells were determined. Analysis for number of intramammary infections indicated no significant differences among treatments for number of infected available quarters. Trend for intramammary infections was that as pulsation ratio widened, the number of infected available quarters increased, especially at the ratio 70:30. As vacuum increased, number of infected available quarters increased. Least squares means of Wisconsin Mastitis Test scores were 6.29, 5.57, and 6.68 for 33.3 kPa; 12.18, 3.82, and 7.86 for 41.6 kPa; and 9.11, 6.40, and 15.02 for 50 kPa at pulsation ratios 50:50, 60:40, and 70:30. There were significant differences among treatments for vacuum and pulsation ratio. Wisconsin Mastitis Test data indicated an interaction between vacuum and pulsation ratio. Optimum predicted vacuum and pulsation ratio based on Wisconsin Mastitis Test data were 27.2 kPa and 62:38.

Animals↗

PubMed1982

Effects of premilking udder preparation on environmental bacterial contamination of milk.

Premilking udder preparations varied wetness and cleanliness of udders and teats at machine attachment. In Experiment I, in a prep stall with manual drying of teats only, udder surface drainage during milking increased standard plate counts compared to preparations with dryer udder surfaces at machine attachment. In Experiment 2, use of prep stall only and no udder and teat preparation had higher standard plate counts than preparations by prep stall with manual drying of udder and teats and by wet paper towels in wetting and cleaning and dry paper towels in drying teats. No preparation of udder and teats had higher standard plate count attributed to soiled teats at machine attachment. Udder surfaces should be dry, and teats should be clean and dry at machine attachment. Premilking udder preparations can affect milk quality as measured by milk bacterial count.

Animals↗

PubMed1978

Development of the conceptus in the bovine.

Growth of fetuses, fetal membranes, and fetal fluids was characterized by least squares analysis for 254 conceptuses ranging from 25 to 278 days of gestation. Prior to 100 days of gestation, increases in allantoic fluid volume and chorio-allantoic membrane weight preceded those of fetal weight, amnio-allantoic membrane weight, and amniotic fluid volume. The relative rate of growth of components suggests a prerequisite of chorio-allantoic membrane expansion for subsequent fetal growth. Male fetuses were heavier than female fetuses as early as 100 days of gestation. Rate of growth of all fetuses was maximal at 230 days of gestation with a peak rate of greater than 200 g/day. Growth rate then declined to less than 100 g/day by term.

Allantois↗

PubMed1976

Detection and characterization of differences in plasma corticoid response to treatments.

Ten experiments involving 3013 observations and 103 animals were studied to characterize variation associated with bovine plasma corticoid concentrations (ng/ml). Total corticoids, corticosterone, or cortisol were measured by competitve protein binding assay. Animals were noncystic or cystic, and measurements were made to establish basal concentrations or to estimate response to stimulation by adrenocorticotrophic hormone injection. Data were analyzed by least squares with the nested model: treatment regimen, animal in treatment, sample in animal in treatment, and sampling time to the highest order of regression (up to seventh) which was statistically significant (P less than .05). Estimates of error variances ranged from .31 for basal cortisol in cystic animals to 233.27 for total corticoids in noncystic, stimulated animals. Coefficients of variation among experiments ranged from 33 to 87% with mean 61%. In most analyses, estimates of experimental error were large indicating need for careful attention to experimental design to insure efficient least-cost experimentation. Use of the power function for nested analysis of variance to accomplish this is demonstrated.

Adrenal Cortex Hormones↗