Pathological studies on systemic mycoses in calves.

Systemic mycoses were found in 19 (4.7%) of 406 calves less than 6 months old which were autopsied during the past 10 years. Alimentary mycosis occurred in 12 (63.2%) of 19 cases. In alimentary mycosis, mucormycosis showed the highest rate of occurrence (91.7%, 11/12 calves) followed by aspergillosis 41.7% and candidiasis was 9.3%. Mucormycosis and aspergillosis were characterized by focal hemorrhagic necroses with hyphal proliferation and thrombi in the mucosa and muscular layers of the forestomach, abomasum, and small intestine. Candidiasis was characterized by hyperkeratosis with pseudohyphae and microconidia in the mucosa of the omasum. Four of 12 calves (33.3%) had mixed infections of the alimentary tract consisting of Mucorales and Aspergillus species. Pulmonary aspergillosis was found in 10 (52.6%) of 19 calves. There were micro-abscesses with hyphal proliferation or asteroid bodies in the lungs. Infections involving both the alimentary tract and respiratory organs were noted in 3 (10.5%) of 19 calves. Disseminated mycosis was found only in one calf. In alimentary mycosis, administration of antibiotics for the treatment of diarrhea and early weaning were thought to be an important predisposing factor.     

Pathological and microbiological studies on pneumonic lungs from Danish calves

During 1 year, the association between microbiological and pathological findings in 72 lungs from calves submitted to the Danish Veterinary Laboratory for diagnostic purposes was studied. All cases were evaluated pathologically and bacteriologically, whereas only 68 cases were examined for the presence of bovine respiratory syncytial virus (BRSV), parainfluenza-3 virus (PI-3 virus) and bovine coronavirus, 62 cases for bovine viral diarrhoea virus (BVD), 45 cases for bovine adenovirus and 51 cases for mycoplasmas. Based on histopathological examination, the cases were diagnosed as fibrinous and/or necrotizing bronchopneumonia, suppurative bronchopneumonia, embolic pneumonia and others. The diagnoses were based on the dominating and most severe lesions in each lung. Haemophilus somnus, Pasteurella multocida, Actinomyces pyogenes, P. haemolytica and BRSV were the most commonly found bacterial and viral lung pathogens, respectively. Pasteurella spp. and H. somnus were often associated with the more severe fibrinonecrotizing type of bronchopneumonia, whereas BRSV was primarily detected in cases of suppurative bronchopneumonia. Mycoplasma bovis was isolated from one case only, whereas M. dispar, M. bovirhinis and Ureaplasma diversum were present, often concomitantly, in the majority of cases. Aspergillus fumigatus was isolated from one case.     

Pathological and virological studies of experimental parvoviral enteritis in calves

Calves held in isolation showed a progressive decline in maternally derived antibody titres to bovine parvovirus but low concentrations of inhibitors resistant to heat and kaolin treatment persisted as the animals matured. These inhibitors had both haemagglutination inhibition and plaque neutralising activity and were considered to be of non-specific origin. Following oral challenge with bovine parvovirus, calves developed mild to moderate diarrhoea, with lymphopenia and viraemia. Sequential virological and immunofluorescent studies showed that the virus initially infected tonsils and intestinal tract, subsequently spreading to systemic lymphoid tissues. Histological and scanning electron microscopic examinations revealed moderate small intestinal villus atrophy and fusion due to crypt damage, together with lymphoid necrosis predominantly associated with the intestinal tract and thymus. Although the disease was not very severe, this may have been because the low parasite burden in the animals reduced mitotic activity in susceptible tissues.     

Study on diarrhea in young calves. 2. Pathomorphological studies in clinically healthy calves and in calves with diarrhea

Pathological-anatomical and histological investigations were performed in 49 calves aged from 1 to 18 days, 26 of them being affected by diarrhoea, 23 being without clinical signs. In both the groups above all rhinitis, gastritis and typhlocolitis could be observed, thus the affection could be characterized as rhinogastrocolitis. Significant differences only existed between diarrhoea affected and clinical incospicuous calves concerning the macroscopic signs of the colon, periportal infiltrates of the liver and thymus in involution. The peak of inflammatory reaction is in general reached at the 7. to 10. day of life. In concordance with bacteriological findings the results refer to an affection not due to coli infection. Virus etiology may not be excluded and has to be examined in further studies.     

Salmonellosis in young calves

The isolation of three strains of porcine parvovirus from aborted foetal piglets is recorded and the role of this virus as a cause of reproductive failure in pigs is discussed.     

Pathological and toxicological studies of calves fed a high concentration cotton seed meal diet

Feeding a high concentration of cotton seed meal to young calves resulted in death with lesions compatible with gossypol toxicity. Calves were fed two different commercially prepared rations. Free gossypol concentrations in different lots of the 17% protein ration varied from 250 to 380 ppm, and the 13% protein ration varied from 40 to 240 ppm. Serum sorbitol dehydrogenase elevation was the most consistent clinical pathological finding. The mean serum sorbitol dehydrogenase concentrations for moribund, hospitalized, and clinically healthy calves were 277, 34, and 45 units/liter. The mean for sorbitol dehydrogenase concentration for healthy calves not fed cotton seed meal was 18 units/liter. Gross lesions included severe effusion of a high protein content fluid into the body cavities of most calves, edema of the mesentery, and hepatomegaly. The most consistent histological lesion was severe centrilobular hepatic necrosis. Elevated levels of liver gossypol were demonstrated. The mean liver gossypol concentration for three calves was 41.7 micrograms/g on a wet weight basis.     

Effects of cyclophosphamide on the lymphoid tissues and humoral and cellular immune responsiveness of young calves.

Cyclophosphamide (CY) was given IV to 5-month-old calves (ten doses; each dose of 5.0 mg/kg, 2-day intervals between doses). The effects of CY on circulating leukocytes, lymphoid tissues, and the humoral and cellular immune responses were assessed. The numbers of total leukocytes, lymphocytes, and neutrophils and platelets decreased significantly. The lymphocyte population was depleted in the cortex of the thymus and B-dependent areas of the spleen and lymph nodes. Significant decreases occurred in the frequency of the peripheral blood lymphocytes-bearing surface immunoglobulin (Ig) and in serum IgM and IgG concentrations. Primary serum antibody responses to avian erythrocytes and Brucella abortus strain 19 antigens were diminished or delayed. The blastogenic responses of peripheral blood lymphocytes to phytohemagglutinin P, concanavalin A, pokeweed mitogen, and to purified protein derivative and B abortus antigens were enhanced as was the delayed hypersensitivity reaction to the tuberculin skin test. While a diminished humoral immune response was associated with CY treatment, the cell-mediated response was potentiated. The effect of CY was transitory with most variables returning to near base line within 24 days after CY was ceased.     

Aetiology of diarrhoea in young calves

Faeces samples were collected from 302 untreated calves on the day of onset of diarrhoea and from 49 healthy calves at 32 farms experiencing outbreaks of diarrhoea. At least four diarrhoeic calves were sampled on each farm, and samples were examined for rotavirus, coronavirus, cryptosporidium, enterotoxigenic Escherichia coli and Salmonella species. Although all these enteropathogens were excreted more frequently by the diarrhoeic than by the healthy calves, the difference was significant overall only for rotavirus. Rotavirus was excreted by 18 per cent of healthy calves, coronavirus by 4 per cent, cryptosporidium by 14 per cent, and no enterotoxigenic E coli or Salmonella species were detected. The most common enteropathogen in diarrhoeic calves was rotavirus, which was excreted by more than half the diarrhoeic calves on 18 farms. Coronavirus was excreted at a similar high prevalence on one farm, cryptosporidium on five farms and enterotoxigenic E coli on three farms. Concurrent infection with two or more microorganisms occurred in 15 per cent of diarrhoeic calves. There was no difference in the isolation rate of campylobacters between diarrhoeic and healthy calves.     

Focal symmetrical encephalomalacia in young calves

Three cases of focal symmetrical encephalomalacia diagnosed in calves Diffuse fibrosing alveolitis diagnosed in an adult cow Review of abortion in sheep Erysipelas septicaemia in outdoor-reared piglets Fine sawdust bedding associated with pneumonia in layer chicks These are among matters discussed in the disease surveillance report for May from SAC Consulting: Veterinary Services (SAC C VS).