20 June 2011

4 minute read

Reproductive diseases

Carmarthen and Shrewsbury both diagnosed abortion caused by Campylobacter fetus venerealis intermedius infection in dairy herds. In the Carmarthen case, three cows had aborted in a herd of 250 and the Shrewsbury case several mid-gestation abortions had occurred in a Staffordshire herd. Campylobacter fetus venerealis intermedius should be considered as a venereal pathogen, with identical control measures as those adopted for the more familiar C. fetus venerealis. Infertility is not always recognised but infected bulls are considered important for the maintenance of the organism.

Bury diagnosed mycotic abortion in two separate herds. In one case the history indicated the feeding of mouldy hay to be the likely source of infection.

Leahurst diagnosed abortion caused by BHV-1 in a 200 cow dairy herd. The lesions seen in the fetus included multifocal necrotising hepatitis.

Other unusual causes of abortion included Streptococcus pluranimalium reported by Preston and Listeria monocytogenes reported by Truro

Alimentary tract diseases

Penrith isolated Salmonella Typhimurium Phage Type 104 from a 4-month-old suckler calf. There had been three deaths from a group of ten.

Preston identified Salmonella Enteritidis PT4 septicaemia as the cause of sudden death of an 8-month-old beef animal. Subsequent investigation revealed no contact with poultry.

Truro diagnosed five outbreaks of disease caused by Salmonella Mbandaka. Two of the isolates were from faeces from 12-21 day old scouring calves, two were from scouring cows and one was from the small intestinal contents of a cow with suspected milk fever and fatty liver syndrome.

Two dairy calves presenting with ill thrift two weeks after changing to an automatic feeding system were submitted for post-mortem. Fifteen calves had been clinically affected over the previous six weeks from a group of 30. Necropsy revealed Cryptosporidiosis and a high level of chewing louse infestation (Bovicola bovis).

Shrewsbury diagnosed eight incidents of liver fluke infestation in cattle in Staffordshire (4), Shropshire (2), Gwynedd (1) and Powys (1). Six cases were in adult animals, one was in 9 month old fattening animals and one in 18 month old Holstein-Friesian heifers which had poor appetite, weight loss, and mucoid diarrhoea, with some tenesmus. A moderate trichostrongyle count was also identified.

A 2-week-old dairy calf was presented to Penrith for post-mortem with a history of recumbency and scour. Six similarly affected calves had been lost in the previous six weeks. The calves were housed five or six to a pen and were bucket fed and creep feed was offered. At a purulent mycotic rumenitis was diagnosed consistent with rumenal drinking and it was recommended that greater attention to detail was given at the time of feeding

Respiratory Diseases

Penrith identified Bibersteinia trehalosi as the cause of respiratory disease in a 12-month-old Shorthorn dairy heifer which had been found dead with no prior clinical signs observed. It was the second recent death in a group of 22 replacement heifers. The post mortem revealed widespread haemorrhages and accumulation of sero-fibrinous fluid in the abdominal, thoracic and pericardial cavities. The lungs had interlobular oedema and generalised dark red discolouration.

In another case Sutton Bonnington identified the organism as the cause of death of a three-month –old dairy cross calf. The animal had suffered a brief episode of respiratory disease prior to death.

Metabolic Diseases

There were numerous reports of metabolic disease during the month. Carmarthen diagnosed fatty liver syndrome with associated ketosis in a six year old Friesian dairy cow in a herd of 200. The cow was described as having been over fat at calving a week before and had then developed ventral oedema, reduced appetite and reduced milk yield.

Thirsk diagnosed the syndrome in a five-year-old dairy cow with milk drop, four weeks after calving. Biochemical testing revealed a very high BHB and NEFA with normal AST and slightly elevated GLDH, indicating fat mobilisation but with little evidence of liver damage.

Starcross investigate poor fertility and conception rates in four dairy herds. In three herds biochemical profiles revealed elevated NEFA concentrations suggesting a negative energy balance may have been playing a role. In the fourth herd low GSH-Px and iodine levels were also detected.

Leahurst examined three cows from a dairy herd where problems had been experienced followed the feeding of a forage extender consisting of citrus pulp, brewer’s grains, biscuit meal and rape meal. Fresh cows refused to eat it, although other cows appeared to find it palatable. Five or six cases of displaced abomasum followed and all but one of these affected animals died. Evidence of Fatty liver syndrome was found in two animals and bacterial endocarditis, a result of a primary rumen acidosis, was detected in the third.

Skin Diseases

Three more cases of psoroptic mange in cattle were diagnosed this month. It is usually impossible to move the animals out of the infected environment at this time of year, making successful treatment difficult. Bovicola bovis (chewing lice) were also present in one case.

Nervous Diseases

Listeria monocytogenes was isolated, following cold enrichment, from the brainstem of a 4-month-old crossbred bull calf from a small dairy herd of 40 cows. It had been ill for 4 days when it was euthanased, having developed ataxia, circling and nystagmus. Necropsy at Leahurst evidence of meningitis on the ventral aspects of the brainstem and in the area of cerebellar peduncles and subsequent histopathology confirmed listeriosis.