Border disease of sheep: spinal cord morphometry.

Semi-automated planimetry was used to determine cross-sectional areas of spinal grey and white matter by direct microscopy of paraffin sections of spinal cord from Border disease (BD) and normal lambs at segments C4, C8, T6 and L4. Spinal cord cross-sectional area was significantly reduced in cases of BD produced by either intramuscular or intranasal inoculation of ewes in the first half of pregnancy with Weybridge strains of BD virus. The reduction was apparent at all 4 levels and in both grey and white matter, though the white matter was the more severely affected. Spinal cord areas tended to be smaller in the progeny of ewes exposed earlier in gestation or to larger doses of virus, but these differences were not statistically significant.

Congenital tremor type AI: light and electron microscopical observations on the spinal cords of affected piglets.

The histology and ultrastructure of the spinal white matter from the dorsolateral funiculus of the third cervical segment was studied in normal control pigs and pigs whose dams were inoculated with the Weybridge congenital tremor strain of swine fever virus in early pregnancy. Only inoculated sows produced abnormal piglets. These showed congenital tremors and ataxia. The severity of clinical signs was related to the degree of spinal myelin deficiency. Morphologically this was quantified by determination of the thickness of myelin investing axons classed according to their diameter. In clinically affected pigs fewer axons were myelinated than normal. Though the myelin sheath thickness increased with increasing axon diameter in all pigs whether clinically normal or not, the increase was less in moderately affected and much less in severely affected pigs. The deficiency of spinal myelin was probably due to delayed or sub-normal myelination accompanied by paranodal myelin abnormalities, myelin degeneration and remyelination.

Detection of antibodies against infectious bursal disease virus: a comparison of three serological methods.

Four different oil emulsion infectious bursal disease virus (IBDV) vaccines were inoculated into four-week-old specific pathogen-free chickens. At weekly intervals for five weeks, sera were obtained from the vaccinated birds and from uninoculated control birds and examined for antibodies against IBDV by enzyme-linked immunosorbent assay (ELISA), the quantitative agar gel precipitin (QAGP) test and the virus neutralisation (VN) test. There was a highly significant correlation between the mean responses to all tests; the highest correlation (0.818) was between VN and QAGP and the lowest (0.573) between QAGP and ELISA. Generally the ELISA detected positive sera earlier than the VN test which in turn was more sensitive than the QAGP test. The ELISA and QAGP test were less variable, more reproducible and easier to perform than the VN test.

A semi-quantitative spot test for glutathione peroxidase in blood of cattle and sheep for the assessemt of biological selenium status.

A method is described for a simple semi-quantitative spot test for glutathione peroxidase in blood of cattle and sheep. The results can be used to place a group of samples from the same herd or flock into one of three blood selenium categories, ie, deficient, low marginal and marginal/adequate.

Estimation of the developmental age of the ovine fetus and lamb.

Fifty-six fetuses and 33 lambs were obtained from a flock of ewes at set gestational intervals between 50 to 180 days after conception. The fetuses and lambs were killed, disected and the sizes and weights of a wide range of skeletal and soft tissues were measured. Five morphological parameters emerged as most suitable for the determination of normal foetal developmental age. By plotting the mean value and ninety-five per cent tolerance limits, the rates of growth and the variability of each parameter were studied. Crown-anus length is useful for determining fetal developmental age from 50 to 100 days gestation; brain weight, long bone length and the number of appendicular ossification centres can be used to determine fetal development age from 50 days gestation until term.

Renal cysts in pigs: prevalence and pathology in slaughtered pigs from a single herd.

An abattoir investigation into kidney condemnations due to renal cysts in pork pigs from one producer showed a prevalence of 47.5 per cent. Affected pigs were the progeny of a landrace boar. Similar cysts found in a small sample of day-old piglets sired by the same boar indicated a congenital origin. A marked variation in size and frequency of cysts in the kidneys of slaughtered pigs was seen, some resembling the severity of polycystic kidneys. Histologically cysts appeared to be of tubular origin. The prevalence of affected pigs in slaughter groups from the single herd could be genetically determined. If this were so the data would be consistent with autosomal dominant inheritance. A breeding experiment to examine this hypothesis is in progress.

Incidence of hypocupraemia in cattle in the east Midlands.

Serum copper values were determined on composite samples from cattle herds in the Midland counties of Derbyshire, Leicestershire and Nottinghamshire. Sampling took place over a period of 17 months and the results indicate that hypocupraemia existed in many herds. The lowest values were found in heifer group samples and the lowest of these was found in Derbyshire. The geographical and management factors which may affect the copper status of herds in this area are discussed.

Practical application of bovine tuberculin PPD in testing cattle in Great Britain.

A national tuberculin testing trial was carried out in 8151 cattle in 132 herds due for normal herd testing and distributed throughout the 11 animal health administrative regions of England, Scotland and Wales. The numbers selected from each region were in approximately equal proportions to the total cattle populations of the regions and comprised a representative sample of the national herd. The standard intradermal comparative tuberculin test using Weybridge avian and human purified protein derivatives (PPD) was carried out on one side of the neck, and Rotterdam bovine PPD (1 X 0 mg per ml) was injected on the opposite side in the usual 'mammalian' site. Of the cattle tested, 9 X 4 per cent were classified as positive reactors to a single intradermal injection of the bovine tuberculin applying the official EEC interpretation for tuberculin tests. A single intradermal injection of human PPD would have resulted in a significantly higher proportion (10 X 4 per cent) of cattle being designated for removal. The rules of interpretation developed by Lesslie and Hebert (1975) for a comparative tuberculin test using avian and bovine PPDs, when applied to this sample, classified 0 X 80 per cent as inconclusive reactors compared with 0 X 58 per cent for the avian/human comparative test. The avian/bovine test also classified as positive reactors 0 X 12 per cent of the cattle tested, whilst the avian/human test classified as positive 0 X 05 per cent of cattle in routine herd tests during the three-year period 1972 to 1974.

Canine parvovirus serology: a collaborative assay.

Fifteen laboratories were supplied with coded samples of canine sera for testing for the presence of antibodies against canine parvoviruses. One of these sera had been designated as a potential British standard canine parvovirus antiserum. Most of these laboratories were either providing a canine parvovirus serology service, or represented pharmaceutical companies which manufacture canine parvovirus vaccines for the United Kingdom market. No attempt was made to influence the test methods used. Thirteen of the laboratories used a haemagglutination inhibition test, three an enzyme-linked immunosorbent assay (ELISA), and two performed serum neutralisation tests. Three laboratories used two different techniques. Adequate analysis was possible only with the results of the haemagglutination inhibition tests. The variability of the results between laboratories could be partly controlled by the use of the standard serum. Much of the residual variability was associated with particular laboratories. The results from the vaccine manufacturers tended to be less variable than those from the diagnostic laboratories.

Atrophic rhinitis: snout morphometry for quantitative assessment of conchal atrophy.

Morphometric methods, either point counting or semiautomated planimetry, can be applied to photographic or impression prints of sections of the pig snout to measure the extent of conchal atrophy on a continuous scale as a morphometric index. Though relatively time consuming, the technique yields highly repeatable parametric data which do not depend heavily on expert, subjective judgment. It is therefore particularly suitable for quantitative analysis of the effects of experimental treatments or changes in management.

Estimation of the developmental age of the bovine fetus and newborn calf.

Jersey cows from several herds provided 97 fetuses and 24 calves at fixed gestational intervals between 80 and 290 days after conception. The fetuses and calves were killed, weighed and measured and, after dissection, the sizes and weights of a range of skeletal and soft tissues were recorded. Six morphological measurements emerged as most suitable for the determination of developmental age in the normal fetus. By plotting their mean values and 95 per cent tolerance limits, the rates of growth and the variability of each measurement were defined. Long bone length was the most useful single measurement for predicting the developmental age of the fetus. Brain weight, bodyweight, crown-anus length and long bone length showed curvilinear growth patterns; age prediction equations derived from these measurements are complicated to use and additional simplified formulae have been derived. The number of appendicular ossification centres also had predictive value, but it could not be used to determine fetal developmental age between 100 and 160 days gestation.

Bovine mycotic abortion: some epidemiological aspects.

Records from 898 cases of bovine mycotic abortion occurring over the five years 1969 to 1974 in South Wales were examined with particular reference to incidence and climate. Mean incidence was lowest in September and highest in January and February. Annual incidence of Aspergillus-type infection decreased but that of Mucortype did not alter significantly. Most abortions occurred during the last trimester of pregnancy. The abortion rate for cattle fed hay in cowsheds was extremely high compared with that for other management systems. No correlation could be detected between total rainfall or number of raindays in June and September and mycotic abortions occurring over the succeeding 12 months. Fungal abortion was followed by pregnancy in most cases where subsequent breeding performance was known.

Biochemical indicators of liver injury in calves with experimental fascioliasis.

Twenty calves were infected with 1000 metacercariae of Fasciola hepatica, the activities of 10 enzymes in plasma or serum were assayed and concentrations in serum of proteins, urea and bilirubin were determined. These values were compared with control data obtained from 14 uninfected calves. Aspartate aminotransferase, lactate dehydrogenase, sorbitol dehydrogenase, glutamate dehydrogenase, ornithine carbamoyl transferase and gamma-glutamyl transpeptidase activities increased in infected calves. Total serum protein increased, albumin decreased, globulin increased and the albumin/globulin ratio was decreased in infected calves. Plasma alanine aminotransferase, leucine aminopeptidase, alkaline phosphatase and cholinesterase activities and serum concentration of urea and bilirubin were unaffected. It was concluded that glutamate dehydrogenase and gamma-glutamyl transpeptidase were the most sensitive indicators of liver cell damage in fascioliasis.

Bovine virus diarrhoea-mucosal disease virus-induced fetopathy in cattle: Efficacy of prophylactic maternal pre-exposure.

Maternal immunity was produced in Jersey heifers by exposing them to bovine virus diarrhoea-mucosal disease virus before conception. In the following pregnancy this immunity protected the fetuses from transplacental infection arising from challenge of the dams at 100 days gestation with homologous virus. Unprotected Jersey heifers showed a high incidence of death and fetal intrauterine growth retardation associated with transplacental viral infection. Functional normality of the locomotor system was assessed retrospectively from ciné films of each calf after birth, and scored for each of an overlapping series of clinical signs. The progeny of non-immune dams scored significantly lower than calves from the vaccinated heifers.

Ovine coccidiosis: studies on the pathogenicity of Eimeria ovinoidalis and E. crandallis in conventionally-reared lambs, including possible effects of passive immunity.

No pathogenic effect was detected in lambs when 10(4) oocyts of each species were inoculated before 72 h of age. At 4 weeks of age the combined inoculum caused diarrhoea and weight loss, the severity being roughly proportional to the size of the inoculum. Even 1000 oocysts of each species caused diarrhoea; the pathogenic effect was attributable mainly to E. ovinoidalis. Hyperimmunization of ewes during pregnancy (by repeated inoculation of massive doses of oocysts) reduced the effects of oocyst inoculation in their progeny. Levamisole administration during pregnancy increased the birthweight of lambs.