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Biomedical subjects

R A Willoughby

Publications and source records attributed to R A Willoughby.

At least 19 recordsLinked to original sources
PubMed1997

Infectious agents in acute respiratory disease in horses in Ontario.

A study of acute respiratory disease in horses in Ontario was undertaken to determine the identity of current causative infectious agents. A nasopharyngeal swab was designed and utilized to maximize isolation of viruses, mycoplasma, and pathogenic bacteria. Serum samples were collected for parallel determination of antibody titers to equine influenza virus type A subtype 1 (H7N7) and subtype 2 (H3N8), equine rhinovirus types 1 and 2, equine herpesvirus type 1, Mycoplasma equirhinius, and Mycoplasma felis. Equine rhinovirus type 2 was recovered from 28/92 horses tested, and equine influenza virus type A, subtype 2, was recovered from 5. The mycoplasma and bacteria isolated were consistent with those commonly associated with nonspecific respiratory diseases in horses, except that Streptococcus pneumoniae capsular type 3 was isolated from 10 horses.

Acute Disease↗
PubMed1991

Use of scintigraphy for the determination of mucociliary clearance rates in normal, sedated, diseased and exercised horses.

Mucociliary clearance rates from the trachea were determined in normal, sedated, diseased and exercised horses from scintigraphs obtained after an injection of technetium-99m sulphide colloid into the tracheal lumen. The group mean tracheal clearance rate of eight clinically normal horses during 42 trials was 2.06 +/- 0.38 cm/min. Significant between horse differences were found (p less than 0.05). When six and seven of these horses were given xylazine and detomidine hydrochloride, respectively, mean group tracheal clearance rates dropped significantly (p less than 0.05). The decreases from each normal horse's mean tracheal clearance rate ranged from 18 to 54%. There did not appear to be a difference between the tracheal clearance rates (TCRs) of the normal horses and those with chronic respiratory disease. Postexercise evaluations were not significantly different from the pre-exercise TCRs in three clinically normal horses and three horses with chronic obstructive pulmonary disease (p greater than 0.05). This minimally invasive scintigraphic technique for determining TCRs has proved to be useful and reliable.

Animals↗
PubMed1989

Use of high-speed cinematography and computer generated gait diagrams for the study of equine hindlimb kinematics.

High-speed cinematography with computer aided analysis was used to study equine hindlimb kinematics. Eight horses were filmed at the trot or the pace. Filming was done from the side (lateral) and the back (caudal). Parameters measured from the lateral filming included the heights of the tuber coxae and tailhead, protraction and retraction of the hoof and angular changes of the tarsus and stifle. Abduction and adduction of the limb and tarsal height changes were measured from the caudal filming. The maximum and minimum values plus the standard deviations and coefficients of variations are presented in tabular form. Three gait diagrams were constructed to represent stifle angle versus tarsal angle, metatarsophalangeal height versus protraction-retraction (fetlock height diagram) and tuber coxae and tailhead height versus stride (pelvic height diagram). Application of the technique to the group of horses revealed good repeatability of the gait diagrams within a limb and the diagrams appeared to be sensitive indicators of left/right asymmetries.

Animals↗
PubMed1988

Bronchoalveolar lavage of cranial and caudal lung regions in selected normal calves: cellular, microbiological, immunoglobulin, serological and histological variables.

Of a group of 30 clinically normal male Holstein calves two to eight weeks of age, six two week old and six four week old calves met various radiographical and clinicopathological criteria for normality. Bronchoalveolar lavage was performed by fiberoptic bronchoscopy on cranial and caudal lung regions in all 30 calves and samples analyzed for free cells, microorganisms, and immunoglobulins. Lateral chest radiographs and lung biopsies were also conducted on each calf. Calves were euthanized and necropsied ten days after bronchoalveolar lavage was conducted. Reported in this paper are results from the 12 normal calves. Microorganisms were present in small numbers in the lower respiratory tract of some normal calves. There were no differences in the above parameters between cranial and caudal lobes. There were statistically significant changes in bronchoalveolar lavage cell proportions with age although there were no detectable differences in clinical signs. Four week old calves had a lower percentage of macrophages and a higher percentage of epithelial cells than two week old animals (p less than 0.05). There was also a trend toward an increased percentage of neutrophils in older calves but this was not significant (p greater than 0.05). Total bronchoalveolar lavage protein also appeared to increase with age (p less than 0.05). In both groups a higher proportion of IgG2 in bronchoalveolar lavage compared to serum was found, suggesting the presence of a local selective transfer mechanism into respiratory secretions.

Animals↗
PubMed1983

Influenza hemagglutination inhibiting activity in respiratory mucus from horses with chronic obstructive pulmonary disorders (heaves syndrome).

Samples of mucus from the lower trachea were collected from 53 horses with chronic obstructive pulmonary disease and from 24 clinically normal horses. Serum samples were collected from 35 of the horses with chronic obstructive pulmonary disease and from the 24 normal horses. Samples were tested for inhibition of hemagglutination by influenza A equine 1 and 2 viruses. There were high levels of hemagglutination inhibiting activity against influenza A equine 1 in mucus samples from horses with chronic obstructive pulmonary disease.

Animals↗
PubMed1979

Pulmonary function testing in horses.

Pulmonary function tests in horses are in the early stages of development and there will be a limit in the range of tests available since those requiring patient cooperation cannot be conducted in animals. Some tests such as blood gas analysis, A-aDo2 and delta Ppl measurements could presently be used to a greater extent under field conditions. Others that require expensive equipment and considerable technical assistance will be limited to the larger referral type veterinary clinics until the time is reached when there is adequate information to select those procedures that give a reasonable cost to benefit ratio to make their use more widespread.

Animals↗
PubMed1979

The rates and patterns of survivorship and disease in a university dairy herd.

The rates and patterns of disease occurrence and survivorship were determined over a six year period in a university operated dairy herd. Of the ten diseases selected for study, clinical mastitis occurred most frequently with an incidence rate of 10.1% and displaced abomasum occurred least frequently with an incidence rate of 4.4%. The occurrence of all disease except those of the ovary was associated with the age of the cow. Mastitis, pneumonia and cystic graafian follicles tended to reoccur in the same cow after the initial occurrence. The average culling rate was 25.6% and the median number of years cows survived in the herd was 3.4 years. Methods for calculating the various rates and survivorship are described and their interpretation discussed.

Animals↗
PubMed1979

The association between disease, production and culling in a university dairy herd.

The impact of ten diseases of dairy cattle on milk production, calving interval and culling were studied in a university operated dairy herd. Cows with clinical mastitis, ketosis or displaced abomasum had lowered milk production. Cows with metritis, retained placenta, cystic graafian follicles or ovarian hypofunction had longer calving intervals. Cows with clinical mastitis, metritis, pneumonia or retained placenta had increased risks of culling. The relationship between disease and culling was based on the medical history of culled and nonculled cows using a case control approach. Therefore, it is likely that in many cases, the association between disease and culling is due to the impact of that disease on productivity.

Animals↗
PubMed1977

Electrophoretic studies on alkaline phosphatases in normal and zinc intoxicated rats.

Polyacrylamide gel electrophoresis was used to characterize the isoenzymes of serum alkaline phosphatase in the rat. The electrophoresis of serum from normal rats resulted in two bands of alkaline phosphatase activity. A prominent band in serum corresponded in electrophoretic mobility to the alkaline phosphatase from bone and intestinal tissue extracts and also a slower migrating liver isoenzyme. A less prominent, fast migrating band in serum had a mobility similar to a faster migrating liver tissue extract isoenzyme. This band only represented 1-2% of the total alkaline phosphatase present in the serum of normal rats but approximately 15% of the total alkaline phosphatase in the serum of rats fed excess levels of zinc. The study also revealed an alteration in the electrophoretic mobility of alkaline phosphatase in bone homogenate by the addition of deactivated serum to the homogenate. The addition of deactivated serum did not alter the electrophoretic mobility of the liver and intestinal alkaline phosphatases in rats.

Alkaline Phosphatase↗
PubMed1974

The Piromen Test as an assay of bone marrow granulocyte reserves in the calf. I. Studies on bone marrow and peripheral blood leukocytes.

The use of Piromen, a polysaccharide complex of Pseudomonas aeroginosa, has been investigated in 21 calves by a test of marrow granulocyte reserves. The maximal increase in peripheral granulocytes (DeltaG) was determined following multiple intravenous and sub-cutaneous injections of Piromen at various time intervals and was correlated with the mature marrow granulocytes on bone marrow smear differentials. Five ug Piromen per kg body weight, by the subcutaneous route, was found to give a mean DeltaG of 5200/mm(3), very similar to the DeltaG of 5300/mm(3) obtained in man with 0.1 ug/kg intravenous Piromen injections. Clinical effects in calves were minimal with the subcutaneous route as compared to the response following intravenous Piromen injections.

Animals↗
PubMed1972

Studies on diarrhea in neonatal calves: the plasma proteins of normal and diarrheic calves during the first ten days of age.

The concentration of serum proteins and plasma fibrinogen were determined in 151 normal and 49 diarrheic calves at intervals from birth to ten days of age. There were significant differences in the concentrations of the various serum proteins in normal calves when the results were analysed at six age intervals. There was no significant relationship between the concentration of the various proteins and the season of the year. Of the diarrheic calves, those that died had significantly lower gamma globulin concentrations than the other calves. Severely diarrheic and dehydrated calves had significantly increased serum albumin and alpha glabulin concentrations and decreased gamma globulin concentrations. No significant variation occurred in total serum protein concentration. Plasma fibrinogen concentrations were similar in normal and diarrheic calves.

Alpha-Globulins↗