PubMed Health⌕ Search

Biomedical subjects

K L Morgan

Publications and source records attributed to K L Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1996

Role of neonatal and maternal risk factors in the faecal soiling of lambs.

A total of 1300 lambs from eight spring-lambing flocks in the south west of England were studied from birth to approximately six months of age. Within the first week of life a number of variables were recorded including the lambs' birth weight, sex, faecal consistency, 48- to 72-hour immunoglobulin status and the condition score and extent of faecal soiling (dag score) of the ewe. Between two and six months of age the lambs were inspected every two weeks and their dag score was recorded. The relationship between neonatal and maternal factors and the risk of becoming faecally soiled later in life (defined as a dag score of 3 or more) was estimated by survival analysis techniques and proportional hazards modelling. There was a significant increase in the rate of faecal soiling of lambs that had experienced a period of watery diarrhoea during the neonatal period (adjusted hazard ratio 1.78, P = 0.01), and lambs that were born to ewes with a high dag score (adjusted hazard ratio 1.48, P = 0.004). The lamb's birth weight was negatively correlated and its age was positively correlated with the rate at which they became faecally soiled. The results are discussed with reference to the determinants of susceptibility to blowfly strike.

Animals↗
PubMed1996

A case control study of blowfly strike in lambs.

A case control study of the risk factors associated with blowfly strike was conducted on 11 farms in the south west of England. For each case, three control lambs were randomly selected from the remainder of the flock. Samples of blood, faeces and wool were taken from the cases and controls, and measurements of weight, dag score (faecal soiling), fleece length, crimp frequency and tail length were made. Conditional logistic regression was used to examine the univariate and multivariate relationships between the independent variables and the rate of blowfly strike. Case lambs had significantly higher dag scores and lower crimp frequencies than their matched controls, although the association with crimp frequency was confounded by dag score. The relationship between blowfly strike and fleece length was also strongly confounded by dag score. After stratifying by dag score, case lambs had shorter fleeces than their controls. Lambs with blowfly strike had significantly higher levels of blood copper and significantly lower levels of blood urea.

Animals↗
PubMed1996

Immunisation regimes used to elevate serum IgE in sheep.

Six different immunisation regimes were used in an attempt to elevate the concentration of ovine IgE. The response was measured by a passive cutaneous anaphylaxis (PCA) test. These regimes included infection with Ascaris suum and the combination of infection and parenteral administration of Ascaris antigens and ovalbumin in adjuvants. The regime producing the highest titre of IgE was the combination of Ascaris infection with parenteral administration of Ascaris extract in Bordetella pertussis. This regime consistently produced a transient high titre (1:1280-1:2560) of serum IgE 9-12 days after immunisation. The response to ovalbumin was transient and the maximum PCA titre obtained was 1:10.

Administration, Oral↗
PubMed1996

An abattoir-based study of the prevalence of subclinical Johne's disease in adult cattle in south west England.

The prevalance of subclinical Johne's disease was estimated in adult cattle slaughtered at three major abattoirs in south west England. A polymerase chain reaction (PCR) based on IS900 was used to detect Mycobacterium paratuberculosis in intestinal lymph nodes of 1553 cattle. Culture was also carried out on all PCR positive and inconclusive samples. The prevalence of subclinical disease in adult cattle was 3.5% (95% confidence intervals (CI) 2.6-4.7) by PCR and 2.6% (CI 1.8-3.6) by culture. The proportion of the disease in each month ranged from 1.6% (CI 0.2-5.5) in April to 4.6% (CI 2.8-6.9) in November, but the difference was not significant (P > 0.05). The proportion of PCR positive lymph nodes in each abattoir ranged from 2.8% (CI 1.6-4.6) to 4.9% (CI 2.9-7.6), this difference was not significant either (P > 0.05). The prevalence in young cattle was 2.0% (CI 0.6-4.5). The difference between age groups was not statistically significant (P > 0.05).

Abattoirs↗
PubMed1995

Development of DNA probes for the ovine Eimeria species E. crandallis and E. ovinoidalis.

As an alternative to morphological speciation, DNA probes have been developed to identify Eimeria crandallis and E. ovinoidalis, the species associated with ovine coccidiosis. Coccidia-free lambs were infected with pure cultures of E. crandallis and E. ovinoidalis. Oocysts separated from faeces were sporulated and treated to release sporozoites from which DNA was purified. Repetitive DNA sequences were identified by hybridisation and cloned. The specificity of selected clones was tested by hybridisation with dot blots of four other ovine Eimeria species, a mixture of caprine Eimeria species and E. acervulina of the chicken. The probes allowed the detection of DNA equivalent to that present in approximately 1,500 oocysts. To increase the sensitivity of the test, a polymerase chain reaction (PCR) approach was adopted, using oligonucleotide primers specific for the cloned repeats. By this method, less than 10 oocysts of E. ovinoidalis could be reliably detected. In addition to the species-specific probes, other highly repetitive DNA sequences from E. crandallis and E. ovinoidalis were cloned and sequenced; these repeats hybridised to all ovine, caprine and avian Eimeria species tested and contained tandem CGA and putative telomeric repeats.

Animals↗
PubMed1995

The seasonal pattern of sheep blowfly strike in England and Wales.

Information on 4049 cases of sheep blowfly strike on 495 farms in England and Wales was gathered in a longitudinal survey conducted in 1991. The breech was the most commonly infested area, accounting for 70.9% of all strikes recorded. Body strikes accounted for 19.7% and foot strikes 11.4% of all strikes. Early in the season the incidences of both breech and body strikes were higher in ewes than in lambs, but from June to October lamb strikes predominated. The incidence of foot strike was greater in ewes than lambs throughout the year, with a peak incidence in September. Regional differences in strike incidence were evident; the highest overall incidences were recorded in the southern regions of England where peak incidence occurred earlier in the year. The highest monthly incidence risk was recorded in August in the south-east of England where there were 14.2 strikes per 1000 lambs and 4.0 strikes per 1000 ewes at risk. The importance of faecal soiling and ambient temperature are discussed.

Animals↗
PubMed1994

Ectoparasite control on sheep farms in England and Wales: the method, type and timing of insecticidal treatment.

The chemical control of sheep ectoparasites raises important environmental, health and welfare issues. There is increasing concern about the possible harmful effects of pesticides on human health and the role of dipping in the contamination of natural watercourses. A longitudinal survey was conducted in 1991, the last year of compulsory dipping for the control of sheep scab, to obtain information about the chemical control of ectoparasites on 485 farms in England and Wales. Organophosphate insecticides were the most commonly used for both summer and compulsory dipping and for spraying sheep, although many of the products used for spraying sheep were not licensed for this purpose. The early pattern of dipping and spraying appeared to follow the pattern of incidence of blowfly strike although more than 40 per cent of sheep were dipped during the first two weeks of the compulsory dipping period. Compulsory dipping for the control of sheep scab was reduced from two dips to one dip between 1988 and 1989 and removed altogether in 1992. The results from the survey were compared with the results of a previous survey and showed an apparent decline in the use of dipping and an increase in the use of alternative methods of control between 1988 and 1991.

Agriculture↗
PubMed1994

A practice-based survey of the frequency of Johne's disease in south west England.

The frequency of Johne's disease in cattle in south west England was estimated from data collected by telephone interviews with veterinarians and farmers. The response rate was 81.6 per cent. The disease frequency was expressed as the proportion of farms with clinical disease and the cumulative incidence in the infected herds. The proportion of farms affected was 1.0 per cent and the cumulative incidence on those farms was 1.9 per cent per year. Similar values were obtained when diagnosis by faecal examination, post mortem examination and histology was taken into consideration; 0.9 per cent of farms were affected and the cumulative incidence in the infected herds was 2.0 per cent per year. The survey was validated against three external reference points. There was good agreement between the use of vaccine and MAFF records, and the total number of holdings and census data. When the responses of the veterinarians were compared with those of farmers there was also good agreement on the use of vaccine (kappa = 77.8 per cent), the number of cases reported in the last year of diagnosis (r = 0.78) and the total number of cattle in the herds (r = 0.75). However, the results suggested that the total number of cattle holdings was overestimated and consequently the proportion of farms affected may have been underestimated.

Animals↗
PubMed1994

Lamb tail docking: a controlled field study of the effects of tail amputation on health and productivity.

A detailed study of the effects of tail docking on lamb health and productivity was prompted by current concern about the welfare aspects of lamb tail amputation. Using a controlled field trial, comparing over 3000 docked and undocked lambs on seven farms, the effects of tail docking on mortality, blowfly strike and production variables were examined. The incidence of blowfly strike was strongly and consistently higher in undocked than docked lambs (rate ratio 6.03, 95 per cent confidence interval (CI) 2.99 to 12.19 for male lambs and 4.25, 95 per cent CI 2.25 to 8.01 for female lambs). The incidence of faecal soiling of the breech was slightly higher in undocked lambs and was identified as an important independent risk factor for blowfly strike. Both the mortality and production parameters were similar for docked and undocked lambs. It was concluded that tail docking protected against blowfly strike, with little evidence of any detrimental effect on lamb mortality and production.

Amputation, Surgical↗
PubMed1994

A descriptive epidemiological study of coccidiosis in early lambing housed flocks.

Infection with Eimeria sp. was studied in 135 lambs born to 79 ewes in four early lambing housed flocks. In three of these flocks two different coccidiostats (monensin and decoquinate) were administered in the feed. Cohort lambs were examined clinically and a rectal faeces sample taken once a week. Samples with more than 300 oocyts per gram were speciated by morphology. Nine species were identified and Eimeria crandallis was the most prevalent. One of the flocks developed clinical coccidiosis before the introduction of coccidiostats. On the remaining farms no differences in the oocyst excretion rate of infected lambs were found between medicated and non-medicated lambs until Visit 6 nor in the proportion of lambs infected until Visit 8. It is suggested that cocciodiosis may be controlled without coccidiostats, by identification of the risk factors associated with disease. Morphological variation of species and collection of large enough faeces samples from young lambs constitute limiting components for further epidemiological studies of coccidiosis.

Animals↗
PubMed1994

Blowfly strike in England and Wales: the relationship between prevalence and farm and management factors.

In order to develop and evaluate control strategies for blowfly strike, a greater understanding of the epidemiology is essential. A postal survey of sheep farmers yielded information about ten farm and management factors and their relationship to blowfly strike prevalence. The risk of a farm reporting at least one case of blowfly strike increased as flock size and stocking density increased (adjusted odds ratio of 1.13 for an increase in flock size of 100 sheep and 1.38 for an increase in stocking density of ten sheep per hectare). As farm altitude increased, the risk of blowfly strike decreased (adjusted odds ratio 0.67 for an increase in farm altitude of 100 m). The risk of high strike prevalence (more than 2% of sheep struck) decreased as both farm altitude and flock size increased. High strike prevalence was also associated with on-farm sheep carcase disposal (odds ratio 1.35). Farmers in the south-west of England were more likely to report at least one case of blowfly strike and high strike prevalence compared to all other regions.

Agriculture↗
PubMed1994

Zoonotic illness--determining risks and measuring effects: association between current animal exposure and a history of illness in a well characterised rural population in the UK.

STUDY OBJECTIVES: To recruit a representative sample of farmworkers, accurately quantify the range and extent of their animal exposures, and measure the associated risks of illness. DESIGN: Inception cohort. SETTING: The study was undertaken among farmworkers living in five local authority areas in the catchment of Hereford and Preston Public Health Laboratories, England. PARTICIPANTS: A quota sample of 404 people on 255 agricultural holdings took part. The holdings were selected at random from the Ministry of Agriculture, Fisheries and Food register. Altogether 58% of eligible subjects approached agreed to participate. MEASUREMENTS AND MAIN RESULTS: The sample had the same sex distribution as the 1991 census for those giving their occupation as agriculture. The mean age was significantly (p < 0.01) higher (44.6 years v 42.2 years) than that of those giving their occupation as agriculture, forestry or fishing in the census, although the modal range (45-59 years) was the same. At enrollment interviews, subjects individually reported contact with up to nine animal species (mode 4) out of 26 reported in all. Based on the numbers contacted and the frequency and intimacy of contact, scores on a ranked ordinal scale from 0-5 were constructed for each species and frequencies for each score were plotted. Subjects also reported past operations and serious illness. A history of pneumonia was significantly (p < 0.05) associated with a pigeon loft on the farm (relative risk (RR) 7.3) and attending farrowing pigs (RR 6.6), and one of leptospirosis with a rat problem on the farm (RR 28.1). Cattle contact was associated with a significantly lower likelihood (protective) of glandular fever (RR 0.19) and rheumatic or scarlet fever (RR 0.12). These effects were significantly related to rankings of the extent of exposure. CONCLUSIONS: It is possible to recruit a representative sample of farmworkers and measure their animal exposures in great detail. Among these exposures, associations with plausible risk factors for pneumonia and leptospirosis and apparently protective factors for glandular fever, scarlet fever, and rheumatic fever have been demonstrated, which further show a relationship between the extent of exposure and response. These findings can be tested further by examining the relationship of exposures to serological evidence of illness or by further prospective follow up of this and similarly well characterised cohorts, or both.

Adult↗
PubMed1994

Cross-reactivity of ovine IgE with anti-human IgE.

Cross-reactivity between ovine and human IgE was investigated using monoclonal antibodies to human IgE heavy chain. Western immunoblotting, reverse cutaneous anaphylaxis (RCA), passive cutaneous anaphylaxis inhibition (PCAI) and reverse passive cutaneous anaphylaxis (RPCA) tests were all used to assess cross-reactivity between the monoclonals and ovine IgE. No cross-reactivity was demonstrated using Western immunoblotting, RCA and PCAI tests. However, evidence for homology in the region of the molecule concerned with mast cell binding was demonstrated by RPCA performed in sheep skin primed with human myeloma IgE.

Animals↗
PubMed1994

Obtention of ovine IgE from heterohybridoma.

Mesenteric and bronchial lymph node cells from sheep immunized with Ascaris suum antigens in combination with Bordetella pertussis vaccine were fused with mouse myeloma cell lines, P3-X63-Ag8.653, NSO.U and NS1.1.Ag1.1. One heterohybridoma cell line (NS1.1.Ag1.1 x sheep) producing ovine immunoglobulin E was detected by the passive cutaneous anaphylaxis test.

Animals↗