Omasal dilation and displacement in 4 Holstein dairy cows

Cases of omasal dilation and displacement in 4 dairy cows are described. The disease was initially diagnosed by a combination of history and clinical signs that included right-sided abdominal distension, rectal palpation, and decreased milk production. The condition was confirmed by laparotomy or necropsy.

Gastrointestinal aspergillosis and zygomycosis of cattle

Gastrointestinal mycosis was diagnosed in 73 lesions of 32 cattle without a history of engorgement, and tissues of 29 animals were examined histopathologically. The omasum was the target organ for infection, followed by the rumen and reticulum. Acute necrohemorrhagic lesions dominated, with infiltration of neutrophils and thrombosis. The etiologic diagnosis was accomplished by indirect immunohistochemical staining of fungal elements with a panel of mono- and polyclonal antibodies raised against fungal antigens. Aspergillosis and zygomycosis were diagnosed in one or more organs of 11 (34.4%) and 20 (62.5%) cattle, respectively, and dual infections were found in three lesions of two animals. Candidosis was diagnosed in only one case. Hematogenous spread of fungi predominantly to the liver was seen in nine animals. Lymphogenic spread of aspergilli to mesenteric and omasal lymph nodes occurred in one and two animals, respectively. Factors that seemed to predispose to mycotic infection included presence of other diseases and intense antimicrobial therapy. These factors and post-partum status, which included 23 of 29 (79.3%) cows, predisposed to mycosis in several ways, e.g., reflux of acidic abomasal contents into the forestomachs, stasis of proventricular content, metabolic dysfunctions, and stress.

A comparative study of the thickness of the tunica muscularis in the forestomach and abomasum of grey, white and black Karakul lambs

Homozygous grey Karakul lambs are born with a lethal genetic factor responsible for death and weaning age. When put on a high roughage diet under field conditions they develop distended, thin-walled rumens and sand impacted abomasa. Homozygous white Karakul lambs have a similar factor but survive for a longer period. Black Karakul lambs are not affected. The present study was undertaken to compare by image analysis the thickness of the tunica muscularis of the forestomach and abomasum of 24-hour old grey, white and black Karakul lambs. One square centimetre samples were taken from equivalent areas in each case of the rumen, reticulum, omasum and abomasum of 38 embalmed Karakul lambs. Haematoxylin and eosin stained histological sections of each sample were studied with a Vids 2 Image Analyzer and the thickness of the circular and longitudinal muscle layers was measured. An analysis of variance indicated a significant difference between the groups in the thickness of the tunica muscularis of the rumen, reticulum and abomasum; the grey group displaying the thinnest and the black group the thickest. The omasa were not affected. The study indicates a reduction in thickness of the tunica muscularis of the homozygous grey and white lambs when compared to normal black lambs.

Acute disseminated Aspergillosis in a cow with special reference to penetration and spread

Acute disseminated aspergillosis caused by Aspergillus fumigatus is reported in a 4-year-old cow given broad spectrum antibiotics and anti-inflammatory therapy. All stomach compartments were infected and hyphal invasion of gastric blood vessels was the probable source of generalization to the liver, lung and kidneys. Throughout the Peyer's patches of the jejunum there were acute necrotic foci with Aspergillus hyphae and similar foci occurred in the corresponding mesenteric lymph nodes. This points to the Peyer's patches being a portal of entry for A. fumigatus to the lymphatic system of the intestine.

Mycotic omasitis and rumenitis as sequelae to sepsis in dairy cattle: six cases (1979-1986)

Medical records of 6 cows with mycotic rumenitis or omasitis, but no history of grain engorgement, were reviewed. A diagnosis was made at necropsy in all cows, although the condition was suspected before euthanasia in 3 cows. Common clinical findings included inappetence, rumen stasis, fluid rumen contents, and scant, pasty, or loose feces. Postmortem findings included severe ulcerative rumenitis or omasitis, with thrombosis of blood vessels in the submucosa, and branching, septate fungal hyphae abundant in inflamed tissues. In these cows, mycotic omasitis and rumenitis were thought to be sequelae of sepsis, with reflux of abomasal fluid into the forestomach and broad spectrum antimicrobial therapy as possible predisposing factors for mycotic infections.

Ruminant forestomach and abomasal mucormycosis under rumen acidosis

Spores of Absidia corymbifera were inoculated orally into sheep with ruminal acidosis produced by feeding barley. Lesions, which developed in forestomachs of all four inoculated cases, included desquamation of superficial layers of the mucosae and focal necrosis from lamina propria to muscular layers. Granulomatous lesions were in the submucosa of three sheep. Lesions in the abomasum (two sheep) included focal necrosis, diffuse hemorrhages, and infiltration of neutrophils. All lesions were accompanied by mycotic proliferation. These results show that A. corymbifera can invade forestomach mucosae through degenerate epithelium resulting from ruminal acidosis.

Kikuyu poisoning of cattle in New South Wales and its relationship to pasture fungi on kikuyu grass (Pennisetum clandestinum)

In the late summer and autumn of 1980 kikuyu poisoning of cattle was diagnosed on 9 farms in New South Wales resulting in 213 deaths among 1370 cattle at risk. Clinical, autopsy and histopathological findings are described and are consistent with those previously recorded. Kikuyu grass samples from 5 paddocks in which deaths were occurring were examined for the presence of fungi. Myrothecium spp were not present. Fusarium semitectum, F. moniliforme var subglutinans, Penicillium spp and a Phoma sp were the most common fungi isolated but with the exception of F. semitectum were not consistently present. F. semitectum was present in adjacent kikuyu grass paddocks in which deaths were not occurring. Two of the farms had army caterpillar (Mythimna convecta) infestations. Army caterpillar faeces present in these paddocks did not contain Myrothecium spp; the fungi present reflected the population present on the kikuyu grass. These findings do not suggest a mycotic cause for kikuyu poisoning.

Reticulo-omasal stenosis in the cow: differential diagnosis with respect to pyloric stenosis

In the complex called vagal indigestion two main types of stenosis can be distinguished, pyloric stenosis and stenosis between the reticulum and omasum or reticulo-omasal stenosis. Laboratory examinations of blood and rumen fluid were carried out in 10 cows with reticulo-omasal stenosis. The results are discussed with respect to the differential diagnoses of pyloric stenosis. In the cows with reticulo-omasal stenosis no metabolic alkalosis occurred and consequently dehydration and uraemia did not develop. For the clinician valuable points of difference were a more prolonged and chronic course and, on physical examination, the absence of serious circulatory disturbances and the absence of an ammoniacal-uraemic odour in the expired air. The clinical picture of reticulo-omasal stenosis strongly resembles a syndrome described as failure of omasal transport.

Omasal squamous cell carcinoma in a ewe

A squamous cell carcinoma of the omasum is reported in a six year old ewe. Hepatic and local lymph node metastases were present.

Volvulus of the bovine abomasum and omasum

Two cows with right-side volvulus (torsion) of the abomasum and omasum were embalmed, and the viscera were dissected to study the topography and mechanisms of the condition. In both cases, the abomasum and omasum were greatly distended and formed a loop with the cranial part of the duodenum. The loop was twisted 360 degrees counter-clockwise, as viewed from the rear or from the right, around an axis through the lesser omentum. The reticulum was drawn caudally on the right side of the rumen by its attachment to the fundus of the abomasum. Study of a model of the stomach and omenta indicated that the more probable mode of rotation was in a sagittal plane. The mode of rotation made no difference in the result or in the method of reduction, which was deflation and rotation in the opposite direction. pressure and tension damage to the ventral vagal trunk and to the blood vessels would indicate a guarded prognosis.

[Malformation of laminae omasi in cattle (author's transl)]

Ten bovine omasa showing more or less deformed laminae omasi are described and classified into two groups: one group (I) without and one (II) with macroscopically perceptible inflammation. The possibility that groups II and I are two successive stages of the same process in which necrotizing inflammation plays an important role, is pointed out. The malformation of the bovine omasum described in the literature as aplasia or hypoplasia, bears a resemblance to the malformation in group I, and, in this case, necrotizing inflammation also was the probable cause.