Epidemiology of Salmonella typhimurium infection in calves: excretion of S typhimurium in the faeces of calves in different management systems

Twenty-five batches of market-purchased calves, comprising 589 animals on 11 farms, were examined for the excretion of salmonellas for at least 28 days after their arrival. Salmonellas were found in 217 (51 per cent) of 423 calves from 18 of 21 batches on nine farms. The calves were housed in single pens on eight farms and in groups on the others. The trends in new excreters and the proportion of Salmonella typhimurium excreters were similar in both types of housing, a peak of excretion which was slightly higher in single penned calves, being reached 18 to 19 days after arrival. New excreters were found at most samplings in both types of housing, but the peak of new excreters appeared earlier and declined sooner in single penned calves. On average, single penned animals excreted salmonellas longer. Salmonella dublin was found only in single-penned calves, and the trend in excretion was similar to that for S typhimurium in single-penned calves except that the peak was at about 28 days. Prophylactic feeding of antibiotics was practised on nine farms, but appeared to have no influence on the excretion of salmonellas. Salmonellas were isolated from the environment in six of nine farms studied, even after cleaning and disinfection. It is suggested that the persistence of salmonellas in the environment deserves more attention in the formulation of control programmes.     

Experimental Salmonella typhimurium infection in calves.

The paper describes the clinical, bacteriological and pathological findings in experimental Salmonella typhimurium infection in calves. Oral doses of 10(8) and 10(9) organisms produced clinical disease and high mortality; doses ranging from 10(4)--10(7) organisms were less consistent in their action. Jersey calves appeared more susceptible to infection than Friesian calves. The clinical signs in most calves were pyrexia and a characteristic diarrhoea that lasted for up to 11 days; more severe symptoms were seen in the calves that received the higher doses. Following infection, all calves excreted S typhimurium in their faeces, the highest counts being observed in the calves that died. In the calves that survived, counts ranging from 10(2)--10(5)/g faeces occurred continuously for up to a maximum of 20 days and subsequent intermittent excretion occurred in a number of calves. In the calves that died, necrotic enteritis in the ileum and large intestine was the most striking lesion; lesions were uncommon in other organs. The findings are discussed in relation to the pathogenesis, diagnosis and control of the disease.     

Progressive dysphagia in a dog caused by a scirrhous, poorly differentiated perioesophageal carcinoma

Investigation of canine dysphagia is performed by a combination of diagnostic imaging, direct visualisation of the upper gastrointestinal tract, and ancillary diagnostic testing to differentiate between structural and functional causes. Video fluoroscopy may be especially helpful. The case of a seven-year-old Border collie that presented with a history of progressive pharyngeal dysphagia is described. Fluoroscopic investigation was initially suggestive of functional pharyngeal disease, but magnetic resonance imaging and surgical exploration demonstrated the presence of a diffuse, scirrhous, poorly differentiated carcinoma with extensive oesophageal involvement. This case highlights that, in some circumstances, fluoroscopy may occasionally be of limited use in the investigation of dysphagia in the dog.     

Aortic and iliac thrombosis associated with angiosarcoma of skeletal muscle in a dog

A seven-year-old, neutered male greyhound was presented with a history of episodic shifting hindlimb lameness and pain. Ischaemic necrosis of areas of the hindlimb digits and skin and a firm swelling within the medial right thigh musculature were found on physical examination. Investigation demonstrated thrombosis of the terminal aorta and right external iliac artery with ischaemic necrosis of muscular and dermal tissue distal to the sites of thrombosis. The dog was euthanased due to poor prognosis. Necropsy findings were of a poorly differentiated invasive sarcoma of the skeletal muscle of the proximal right hindlimb, thrombosis of the aorta and right external iliac artery and secondary renal glomerulopathy. Immunohistochemistry of the neoplastic tissue indicated angiosarcoma based on expression of CD31 and factor VIII-related antigen. Thrombosis was considered likely to be due to systemic hypercoagulability because of the presence of altered flow characteristics and endothelial damage in the vascular tumour bed. Aortoiliac thrombosis, paraparesis and hindlimb ischaemia are unusual sequelae of angiosarcoma in the dog.     

Fungi isolated from bovine udders,and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources.

METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi.

RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats.

CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi.

CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance.