PubMed Health⌕ Search

Biomedical subjects

R S Morris

Publications and source records attributed to R S Morris.

At least 109 records · Page 6Linked to original sources
PubMed1994

Ovarian derived prorenin-angiotensin cascade in human reproduction.

OBJECTIVE: To review the available literature concerning the renin-angiotensin system of the human and animal ovary and to outline the clinical relevance of this system. DESIGN: The location, function, and regulation of the components of the ovarian prorenin cascade are described. The possible functions of this system as well as its association with common gynecologic problems are also given. CONCLUSIONS: The ovary contains a complete cascade whose end product is the formation of angiotensin II. Angiotensin II may have a role in steroid synthesis, oocyte maturation, ovulation, and corpus luteum formation. Further, aberrations in this system are associated with ovarian tumors, ectopic pregnancy, pre-eclampsia, and ovarian hyperstimulation syndrome.

Angiotensin II↗
PubMed1994

Application of subjective methods to the determination of the likelihood and consequences of the entry of foot-and-mouth disease into New Zealand.

New Zealand has a history of continuous freedom from foot-and-mouth disease and relies on a two-tier system of surveillance to maintain this status. The first involves border control procedures and stringent importation standards, and the second is an exotic disease and pest response programme. As part of an economic evaluation comparing the exotic disease and pest response programme against a hypothetical lower grade ;measured response programme subjective judgements of the risks involved were required. Twenty-eight selected animal health professionals, predominantly veterinarians, were posted a questionnaire that used three techniques (single point estimates, three point estimates and elicitation methods) to determine the risk components in a foot-and-mouth disease outbreak. The two key variables were the probability of an outbreak in New Zealand, and the number of secondary properties to which the disease spread during the epidemic. A Delphi conference of ten selected participants then focused mainly on the two key variables, with a second round postal extension to this group for the first variable. The individual data sets were then analysed and combined using a stochastic simulation technique. The final mean probability of an outbreak was about once in 50 years (0.0199). The mean numbers of farms to which disease would spread during an epidemic under the existing exotic disease and pest response programme, a measured response programme which allowed vaccination and a measured response programme which excluded vaccination were estimated to be 61, 478 and 2230 respectively. The policy implications arising from the quantification of these two key variables are that more expenditure on preparedness is justifiable and current resource planning is barely adequate.

Journal Article↗
PubMed1994

Deer-herd health and production profiling in New Zealand. I. Study design.

A 2-year observational study was conducted on 15 commercial red-deer farms in the North Island of New Zealand, to provide health and production data, and identify risk factors for outcomes including health, reproduction, venison and velvet antler production. About 2,700 hinds, 2,400 weaner deer and 1,500 stags were monitored. Daily management practices, deer performance and health problems were recorded. At 3-monthly visits, samples were collected from deer, pastures and soils. Data were processed by multivariable statistical techniques to identify the most important factors affecting production and health.

Animal Husbandry↗
PubMed1994

Deer herd health and production profiling in New Zealand. 2. Preliminary results.

A 2 yr observational study of 15 commercial red deer farms is being conducted in New Zealand and statistical analysis initiated. Preliminary results for weaner deer growth, reproduction and deer mortality data are presented. Multivariable statistical analyses are used to identify risk factors for these various outcomes. Factors associated with yearling hind conception status were included in a putative path diagram and logistic regression was used to identify important factors.

Animals↗
PubMed1993

The potential extent of transmission of foot-and-mouth disease: a study of the movement of animals and materials in Southland, New Zealand.

A survey of Southland farms was conducted to assess the potential for foot-and-mouth disease dissemination through normal movement patterns of farm animals and materials over a period similar to what would be expected from the time the virus arrived on a property to the time of diagnosis. Each farmer participating in the survey was required to complete a diary, recording all movements of people, animals and materials on to or off a farm during a 14-day period. The mean number of movements recorded per farm was 50. The distribution of movement distances showed the majority of movements occurred within the immediate neighbourhood of the origin, with 31.5% and 59.5% of all movements occurring within 5 km and 10 km respectively. In order to contain 95% of all movements, an area where movement was controlled would have to have a radius of 100 km. The data was then used to construct a spatial simulation model to study the movements off a hypothetical index farm. When secondary movements off primary destinations were included in the model, the mean number of movements to be traced to contain the disease was 100 (range 77-160) for a 14-day simulation period. The area required to contain 95% of all movements tended to increase slightly, depending on the length of simulation run. The mean number of high risk movements that occurred over the 100 km radius was 3.4.

Journal Article↗
PubMed1993

New advances in the treatment of infertility in women with ovarian failure.

Ovarian failure is heterogeneous in etiology and may occur at various points in a woman's life. As such, it may interfere with fertility. Clinical presentation ranges from complete cessation of menses to oligomenorrhea to the continuation of menses with elevated gonadotropins. Various therapies have been used in an attempt to induce fertility, including sex steroids and gonadotropin-releasing hormone agonists to suppress circulating gonadotropin alone or in combination with estrogen or gonadotropin-releasing hormone agonists to induce ovulation. Corticosteroids are also used to overcome autoimmunity. Randomized therapeutic trials are rare and fail to demonstrate any significant improvement in ovulation and pregnancy rates. Donor oocytes have demonstrated high success rates and have proven to be useful in patients with both premature ovarian failure and natural menopause. Pregnancies have been initiated and maintained in women through 60 years of age. Thus, for those accepting of the technique, oocyte donation appears to be the treatment of choice for hypergonadotropic hypogonadism.

Adrenal Cortex Hormones↗
PubMed1992

Hoof growth and wear in pasture-fed dairy cattle.

Hoof growth and wear studies were conducted on ten spring-calving cows over 12 months. The rates of hoof wall growth and wear were lower in autumn and winter than during spring and summer. Both were greater in 2-year-old than in mature cows (p<0.05). Sole wear occurred most rapidly along the abaxial edge of the weight-bearing surface, less quickly in the toe and heel areas, and most slowly in the mid-sole region. Both hoof wall wear and sole wear were greater in lateral digits than in medial digits (p<0.01). Sole concavity, measured using a profile gauge, was greater in 2-year-olds prior to calving than in mature-aged cows (p<0.05) but this difference disappeared soon after calving as concavity was lost in the younger cows. Medial digits almost always had greater concavity than lateral digits. Sole concavity measurements were also made on the hind digits of 24 autumn-calving cows on four occasions at 2-monthly intervals. Prior to calving, concavity was much greater in these cows than in the spring-calving cows. However, concavity was lost rapidly following calving and concavity measurements were soon similar to those found in the spring-calving cows.

Journal Article↗
PubMed1991

A longitudinal study of the hooves of non-lame cows.

A longitudinal study of the feet of cows from a seasonal dairy herd was conducted over a 12 month period to measure the occurrence of subclinical hoof lesions. Eleven 2-year-old cows, entering the herd for the first time, and eleven mature cows were randomly selected from a herd of 415 cows at the end of winter (July 1989) prior to calving. The incidence of lameness in the herd over the 12 months was 2%. None of the trial cows became lame during the study. Cows were examined monthly. The type, severity and location of any hoof lesions were recorded. Sole haemorrhage, erosion of the heel bulb and minor white line separation were the most commonly observed lesions. These lesions were observed with specific claw distributions in the cow and at specific times of the year and breeding season, with waves of each type of lesion passing through the herd at a particular time. White line separation was observed commonly during spring (up to 37% of digits affected), disappeared almost completely over the dry summer months and reappeared in autumn, increasing to 40%' again over winter. Lesions were more commonly observed in the lateral digits, with fore feet being more commonly affected than hind feet. Erosion of the heel bulbs was common in August (65% of digits affected, more common in mature cows than 2-year-olds), disappeared quickly during spring, and reappeared in all cows during the following winter (88% of digits; no age differences). There were no differences in distribution between digits. Sole haemorrhages were concentrated over the mid-sole and abaxial sole zones. They were more common in the hind feet than the front feet and more common in the outside claws (p < 0.001). Haemorrhages were not observed prior to or soon after calving, appeared in October and reached a peak of 40% in December, then gradually disappeared by the time of drying-off in May. The 2-year-olds were more frequently affected than the mature cows (p <0.001).

Journal Article↗
PubMed1991

A case study of lameness in three dairy herds.

All cases of lameness that occurred in cows from three dairy herds between August 198'3 and July 1990 were examined every 2 weeks from the onset of lameness until the lesions resolved. The incidences of herd lameness were 38%, 22% and 2%. Some 186 clinical lesions were identified in 134 cases of lameness in 120 cows. Sole bruising (42%) and white line separation (39%) were the most frequently diagnosed conditions. Lateral digits of the hind limbs were the most affected. The mean time from the onset of lameness to clinical recovery was 27 days and to lesion recovery was 35 days. The peak incidence of lameness occurred during winter for autumn-calving cows and during the late spring for spring-calving cows. The onset of lameness was associated with the stage of lactation and wet weather conditions. Survival analysis revealed that the probability of an individual cow lasting in the milking herd for any specified period of time without becoming lame was highly associated with both her herd environment and her age. Total lactation yields of milk, milk fat and milk protein were lower for cows suffering from lameness than for herd-mates matched on age and proximity on calving date (P<0.05). Reproductive performance was also poorer in lame cows than in their herd-mates.

Journal Article↗
PubMed1991

Information systems for animal health: objectives and components.

As in most other technical and management fields, information management is fast becoming the key to effective action in animal health. A modern veterinary service requires effective systems for gathering relevant information from the field, processing it in ways which provide maximum value, and presenting it in a form which is easy for national policy-makers and field staff to use in implementing appropriate actions to achieve effective disease control. This paper describes seven objectives which should form the basis for developing an integrated national animal health information system. It also specifies six criteria which any information-gathering activity should be required to meet before it is allowed to commence. For each of the seven objectives, a description is given of how the particular component of the system can be used, with examples of how such information management procedures have been implemented in practice. Attention is drawn to other papers in this issue which describe various innovative techniques currently used to meet some of the objectives of a modern animal health information system.

Animal Diseases↗
PubMed1991

Geographic information systems: their application in animal disease control.

Geographic information systems (GIS) are computerised information systems that allow for the capture, storage, manipulation, analysis, display and reporting of geographically referenced data. They have been used in recent years for a wide variety of purposes, including town planning and environmental resource management. The technology has many features which make it ideal for use in animal disease control, including the ability to store information relating to demographic and causal factors and disease incidence on a geographical background, and a variety of spatial analysis functions. A number of possible veterinary applications are suggested, and three examples of the use of GIS in New Zealand are discussed.

Animal Diseases↗
PubMed1989

Forms of employment and species caseload of veterinary practitioners in New Zealand.

A survey by means of a postal questionnaire was undertaken to investigate the patterns of work and the need for information of veterinary practitioners in New Zealand. Of the 670 eligible veterinarians, 399 practitioners (60 per cent) participated in the survey. Of these, 38 per cent were in large animal practice (less than 20 per cent of work devoted to cats and dogs) and 31 per cent were in small animal practice (more than 80 per cent of work with cats and dogs). The remaining 31 per cent were in mixed practice, with a workload intermediate between the other two groups. Across the entire sample of practitioners, cats and dogs took up the largest number of veterinary hours per person (1092 hours per year). Dairy cattle were second (438 hours), and horses third (302 hours). Deer and goats ranked next, and each used more veterinary hours per person than did either sheep or beef cattle. Other species comprised very minor parts of the overall workload. Women spent a much higher proportion of their working hours with small animals and a much lower proportion with horses than did men. For other species workload patterns were similar between men and women. In relation to employment of the practitioner group, women were under represented, compared with men, among those with responsibilities for the management of practices, even when account was taken of the fact that the women in the sample were younger. Fewer than one per cent of men in the sample were not employed full-time, whereas 15 per cent of the women were in part-time employment. The survey indicates that there has been a substantial change in the demographic structure of the veterinary profession and the forms of veterinary work carried out. It also shows that the differences in work and career patterns between men and women need more intensive study to improve the accuracy of predictions of future requirements for veterinary manpower.

Journal Article↗
PubMed1989

Environmental and behavioural factors affecting the prevalence of foot lameness in New Zealand dairy herds - a case-control study.

A case-control study of environmental and behavioural factors influencing foot lameness was undertaken on 62 dairy herds comprising an average of 185 milking cows in Taranaki, New Zealand. Thirty two case herds were identified as having had at least 10 per cent of the cows lame during the milking season in which the herd was studied, and thirty control herds were selected on the basis that no more than 3 per cent of cows in these herds had been lame per year for at least two years immediately prior to investigation. Each herd was visited at both a morning and an afternoon milking, and 58 risk factors were measured between the time the farmer began to assemble the cows for milking and the completion of milking. Comparison of single variables between case and control herds identified 24 which showed differences (p<0.10). These variables were then subjected to stepwise multivariate logistic regression, and statistically significant variables in this analysis were used to create a tentative path diagram of possible causal web relationships between the various risk factors and the outcome variable, the lameness prevalence level. Information from a review of the published literature was used to include further variables to the 24 into the initial (or null hypothesis) path model. Logistic path analysis was then used to eliminate non-significant paths from the diagram, leaving 19 arrows joining 13 variables in the final path diagram, compared with 33 joining 20 variables in the initial version. The most influential variables in explaining variation between case and control herds were the average level of maintenance of the track and the degree of patience shown by the farmer in bringing the cows in for milking. Overall, factors associated with the movement of animals to the milking shed explained 40 per cent of the variation (deviance) with regard to the lameness prevalence level. Risk factors associated with characteristics of the milking process explain 24 per cent, and risk factors associated with characteristics of the cows in the herd explain 9.5 per cent. Recommendations are made on management changes which deserve further investigation as ways of reducing lameness problems in dairy herds.

Journal Article↗
PubMed1988

Demographic profile of the veterinary profession in New Zealand, 1985.

The demographic characteristics of the veterinary profession in New Zealand are examined using information supplied by registered veterinarians to the Veterinary Surgeons Board in their applications for annual practising certificates in 1985. Comparisons are made with the veterinary professions in other similar countries, and with the medical and paramedical professions in New Zealand. In 1985 1308 registered veterinarians were working in New Zealand and 304 were overseas, whereas in 1976 the equivalent figures were 748 and 182. This represents an increase of 73% in the number of registered veterinarians in the last 10 years. Eighteen percent of veterinarians were female. The mean age of veterinarians was 38 years, but females in the profession were on average much younger (32 years) than males (42 years). Clinical practice provides employment for 70% of veterinarians: of these 59% work principally with farm animals and 41% with non-farm animals. The remaining veterinarians are employed by Government (22%), University (5%) and Industry (3%). The current demographic structure of the profession has been markedly influenced by the opening of New Zealand's only veterinary school at Massey University in 1963. Differences from other medical professional populations in New Zealand and overseas principally reflect the marked change in the number and sex ratio of graduates entering the veterinary profession since that time. It will take about another twenty years before the population reaches a stable age and sex structure, assuming that current graduation patterns persist throughout that period. Because the structure of the population is changing, considerable caution is needed in predicting future employment trends from data for a single year.

Journal Article↗