Emerging and established: the work continues.
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Animals↗
Biomedical subjects
F D Menzies
Publications and source records attributed to F D Menzies.
The Northern Ireland programme for the control and eradication of Mycobacterium bovis.
Bovine tuberculosis is endemic in Northern Ireland and a comprehensive eradication scheme has been in operation since 1959. The current programme involves annual testing, extensive computerized tracing, short-interval testing of herds contiguous to outbreaks and compulsory slaughter of positive cattle. Despite initial reductions in disease prevalence, eradication has proved elusive and potential explanatory factors include high cattle density and potential for between-herd contact, the impact of exotic diseases on resource priorities, and significant levels of bovine tuberculosis in a wildlife reservoir, the European badger (Meles meles). Both the role of the infected bovine and that of the badger in spreading disease have to be addressed to ensure progress towards eradication. Current measures are described and future options for enhancing the programme are outlined.
Animals↗
Antimicrobial susceptibility of Campylobacter spp. isolated from broiler chickens in Northern Ireland.
Between February 2000 and October 2001, cloacal swabs were collected from 387 broiler chicken flocks in Northern Ireland. Campylobacter isolates from the 262 positive flocks were tested with common antimicrobial agents using a disc diffusion method and by Etests. Resistance to erythromycin, gentamicin and chloramphenicol was <1%, whereas for ampicillin, nalidixic acid and tetracycline, resistance was 33%, 10% and 13%, respectively. Ciprofloxacin resistance was 3%, one of the lowest in recent reports from studies on human or poultry isolates. Sequence data of the quinolone resistance-determining region of the gyrA gene showed a mutation leading to Thr-86 to Ile substitution among highly resistant ciprofloxacin isolates. Only 0.8% of the isolates studied were resistant to four or more antibiotics.
Animals↗
Risk factors for toxic mastitis in cows.
A case-control study of the management and disease risk factors associated with toxic mastitis in cows was carried out. Seventy-one cases satisfied all the selection criteria, and a subset of 41 cases in which pure growths of Escherichia coil were cultured from milk samples was also investigated. Conditional multiple logistic regression analysis of the 71 cases and matched controls revealed no statistically significant associations. However, among the subset of 41 cases and matched controls, the administration of calcium parenterally at calving (P < 0.01) and assistance at calving (P < 0.01) were both associated with toxic mastitis. Controlling for assistance at calving, the odds of a cow developing E coli toxic mastitis if it had received calcium parenterally at calving were 23 times higher than for a cow that had not received calcium. Similarly, controlling for the administration of calcium at calving, the odds of a cow developing E coli toxic mastitis if it had received assistance at calving were 11 times higher than for a cow that did not receive assistance.
Animal Husbandry↗
Clinical and laboratory findings in cases of toxic mastitis in cows in Northern Ireland.
This paper describes the clinical and laboratory findings from 264 cases of toxic mastitis in cows in Northern Ireland between October 1995 and May 1997. Nearly all the cases occurred during the winter housing period, with 84 per cent occurring between November and March inclusive, and 30 per cent in March. Sixty per cent of the cases occurred within one month of calving, and 29 per cent within four days of calving. The most common clinical signs were lethargy (92 per cent), discoloured milk (90 per cent), anorexia (72 per cent), tachypnoea (23 per cent), diarrhoea (23 per cent), recumbency (18 per cent) and staggering (15 per cent). Severe pyrexia (18 per cent) and clinical dehydration (44 per cent) were relatively common findings. Pure growths of Escherichia coli were isolated from 50 per cent of the milk samples, but 11 per cent yielded no bacterial growth. In vitro sensitivity tests indicated that enrofloxacin was effective against 98 per cent of the bacteria isolated, and framycetin and amoxycillin/clavulanic acid against 91 per cent. Abnormally high blood urea levels were observed in 31 per cent of cases, high blood creatinine levels in 42 per cent, and severe leucopenia in 56 per cent. Of the cases which were followed up, 14 per cent died, 21 per cent were culled early and a further 22 per cent lost milk production from the affected quarter.
Amoxicillin-Potassium Clavulanate Combination↗
Cattle-to-cattle transmission of bovine tuberculosis.
In developed countries, Mycobacterium bovis infection in cattle is now mostly confined to the respiratory system, which reflects transmission and establishment of infection mainly by this route. A single bacillus transported within a droplet nucleus is probably sufficient to establish infection within the bovine lung. Infected cattle should always be considered as potential sources of infection, since studies have demonstrated that a significant proportion of tuberculous cattle excrete M. bovis. In general, the dynamics of M. bovis transmission are poorly understood and the conditions under which a tuberculous animal becomes an effective disseminator of infection are currently not defined although environmental contamination appears to be a less effective method of disease transmission. Field studies indicate a wide spectrum of transmission rates but generally the spread of M. bovis infection is still considered to be a relatively slow process. Slaughter of diseased cattle detected by tuberculin testing and at meat plant inspection has been shown to be an effective policy for tuberculosis eradication, provided there are no other reservoirs of infection and all involved in the cattle industry are committed to a policy of eradication. Epidemiological approaches, particularly case-control studies, seem to provide the best method for quantifying the relative importance of the various sources of M. bovis transmission to cattle and modelling techniques can be used to assist in the design of cost-effective control measures that may lead to tuberculosis eradication.
Animals↗
Aspects of the epizootiology of pancreas disease in farmed Atlantic salmon Salmo salar in Ireland.
A computerised database containing information on over 17.8 million salmon contained within 49 separate marine populations was used to study the epidemiology of pancreas disease (PD) in Ireland. Of the 43 recorded PD outbreaks, 57% occurred in the 3 mo period August to October inclusive (17 to 32 wk post-transfer). Analysis of variance of mortality rates during PD outbreaks occurring on 6 marine sites over a 5 yr period showed that mortality rates vary significantly between sites (p < 0.001) but not between years over this time period. The mortality rate during PD outbreaks ranged from 0.1 to 63%. Mortality rates were significantly higher when PD outbreaks occurred earlier in the year (y = -1.28x + 59, SE of b 0.33). The mean length of a PD outbreak was 112 d (SE = 7.7, n = 37). There was no correlation between PD mortality rate and smolt input weight, initial stocking density and transfer mortality.
Animals↗
Mortality in cattle up to two years old in Northern Ireland during 1992.
A study of bovine mortality involving a stratified random sample of farms and veterinary practices was carried out in Northern Ireland during 1992. In the farm survey over 3500 deaths were reported from 1069 farms and 237 farms reported no deaths. The estimated total number of deaths of cattle up to two years old was 12,332, a figure which excludes an estimated 7921 stillbirths. The estimated annual mortality rates for six- to 24-month-old cattle, one- to five-month-old calves and neonatal calves were 0.79 per cent, 0.82 per cent and 1.02 per cent respectively. The stillbirth rate was 1.86 per cent. Respiratory syndromes were associated with 37 per cent of the deaths of six- to 24-month-old cattle and gastrointestinal syndromes were associated with 22 per cent; in one- to five-month-old calves these syndromes were associated with 37 and 33 per cent of the deaths, respectively. Stillbirths accounted for 62 per cent of all the deaths of calves under one month old, and the neonatal disease complex accounted for 39 per cent of the deaths of calves which were born alive but died within one month of birth.
Age Factors↗
A study of mortality among suckler and dairy cows in Northern Ireland in 1992.
As part of an initiative aimed at reducing the number of cattle deaths in Northern Ireland, a survey of bovine mortality on a stratified random sample of farms and veterinary practices was carried out during 1992. In the farm survey, over 3500 deaths were reported from 1069 farms, with a further 237 farms reporting no deaths during the year. The estimated numbers of deaths of suckler cows and dairy cows were 5997 and 4246, respectively, giving an estimated annual mortality rate of 2.36 per cent for suckler cows and 1.55 per cent for dairy cows. One third of the suckler cows and 19 per cent of the dairy cows were found dead with no previous signs of illness. In the cows in which clinical signs were observed and which received veterinary attention, hypomagnesaemia (20.3 per cent) was the main cause of death in suckler cows and coliform mastitis (12.3 per cent) was the single most important cause of death in dairy cows. Conditions associated with calving accounted for approximately 30 per cent of the deaths in both types of cow.
Aging↗
Prevalence of pleurisy and pneumonia in pigs in Northern Ireland (1969-1989).
A database of condemnation data from abattoirs was combined with a meteorological database to investigate the relationship between the prevalence of pleurisy and pneumonia in pigs in Northern Ireland and prevailing weather conditions. Between 1969 and 1989 three significant trends were found in the occurrence of condemnations due to pleurisy and pneumonia, and significant correlation coefficients were found between the percentage condemnations and air temperature.
Abattoirs↗
A microcomputer model for predicting output from beef suckler herds.
The design of a computer spreadsheet model for predicting the output of beef suckler herds is described and validated with results from three herds. The effects of changing variables in the model on the output of these herds are demonstrated, particularly with respect to changes in herd management.
Animal Husbandry↗
The epidemiology of Ascaris suum infections in pigs in Northern Ireland, 1969-1991.
This paper presents the results of analysis of condemnations of pig livers due to cirrhosis which, in temperature climates, gives an accurate estimation of Ascaris suum infections. Over the 23 years analysed, a very highly significant upward trend in the prevalence of A. suum is demonstrated. The association between the prevalence and the mean air temperature over the early summer period is highlighted. Thorough cleansing of pig units in early spring and at various times during the summer are suggested as the most appropriate control measure.
Abattoirs↗