Enzootic calcinosis in Toggenburg goats in New Zealand.

CASE HISTORY: Necropsies on Toggenburg goats culled from a small farm in the Manawatu district of New Zealand, performed at Massey University (Palmerston North, NZ) over a period of 29 years (1991-2019), revealed soft tissue mineralisation, particularly of cardiovascular tissues. The farm spans 10 acres and runs between 15 and 30 Toggenburg goats. The goats are predominantly on pasture comprising a variety of types. PATHOLOGICAL FINDINGS: Necropsies were performed on all adult goats (n = 45) that died or were euthanised. Histopathology was performed on 42 goats (93%), of which 33 (73%) included sufficient tissues diagnostically relevant to soft tissue mineralisation. The most significant gross findings were in various arteries, with the aorta most commonly affected, followed by the heart and lungs. The aortic intima showed prominent, multifocal to coalescing, raised, wrinkled, white plaques. Microscopically there were multiphasic lesions of mineralisation, chondroid, and osseous metaplasia in the elastic arteries, aorta, heart and lungs. A lumbar vertebra from one goat had prominent, basophilic, fibrillar, tangled matrix lining Haversian canals and lamellae. LABORATORY FINDINGS: Blood samples were collected from 15 adult goats in the affected herd and from 10 adult Toggenburg goats from an unaffected herd. Samples were collected by jugular venipuncture at 2-month intervals for 12 months (April 2018-March 2019). Concentrations of calcium, phosphorus, 25-hydroxyvitamin D2 and D3 (25OHD2, 25OHD3) in serum were analysed. The concentration of total 25OHD in serum was 34.2 (95% CI = 18.9-49.4) nmol/L (p < 0.001) higher in goats from the affected herd than in goats from the unaffected herd. Serum 25OHD2 concentration was 46.2 (95% CI = 39.2-53.2) nmol/L higher (p < 0.001) in goats from the affected herd compared to the unaffected herd. Serum Ca concentrations in affected goats were 0.101 (95% CI = 0.005-0.196) mmol/L higher (p = 0.039) than unaffected goats, but remained within the reference range. There was no evidence of a difference in serum 25OHD3 and P concentration between the herds. VEGETATION SURVEY: All paddocks on the property were surveyed every 2 months along evenly spaced line transects, and then further traversed perpendicularly to form a grid. No known calcinogenic species were identified. Known plant sources of vitamin D identified on the farm included mushrooms (species not defined), Dactylis glomerata, lichen, pine pollen, and algae. DIAGNOSIS: Soft tissue mineralisation and enzootic calcinosis. CLINICAL RELEVANCE: Veterinarians are alerted to the possibility of either enzootic calcinosis in goats and the potential occurrence of calcinogenic plants in New Zealand; or chronic vitamin D toxicosis of non-plant origin.

Postural and gait abnormalities in a group of Romney lambs due to pain induced by severe chronic cutaneous dermatophilosis.

CASE HISTORY: Fifteen lambs from a flock of 1,000, 5-month-old Romney lambs in the Manawatu region of New Zealand, developed unusual postural and gait abnormalities during the summer of 2020. In mid-January, the lambs were grazing a raphanobrassica crop (xRaphanobrassica; Brassica oleracea x Raphanus sativus) but were removed from this crop soon after as they developed dermal lesions on the pinnae consistent with photosensitisation (colloquially known as "rape scald"). The lambs were placed onto a shaded paddock containing a pasture of predominantly perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). One week following removal from the crop (late January), the 15 lambs developed abnormal postures and gaits that were described by farm staff as "neurological" and "swayback-like". CLINICAL FINDINGS: From a distance, all 15 lambs exhibited remarkably similar abnormal posture and gait whereby their weight was borne on their carpi, and they appeared to crawl while walking due to crouched hindquarters and prominent lordosis. Of the affected lambs, five were submitted for clinical examination. All five had normal vital signs. The results of neurological examinations were within normal limits. In response to palpation of the dorsum, the lambs performed an exaggerated and unusual dipping motion, particularly when pressure was applied over the lumbar spine. Parting of the fleece over the dorsum revealed thickened, indurated skin that cracked and tore easily. PATHOLOGICAL FINDINGS: The shorn pelt of a euthanised lamb revealed a large (100 cm × 40 cm), locally extensive, irregular ovoid region of the skin of the dorsum that was markedly thickened, indurated and crusted. Impression smears of the lesions revealed long filamentous chains of plump coccoid bacteria separated by transverse and longitudinal septa, consistent with Dermatophilus congolensis. Histopathology of the lesions revealed severe, chronic-active, locally extensive, necrosuppurative dermatitis with marked acanthosis, orthokeratotic and parakeratotic hyperkeratosis, ulceration, filamentous bacteria and coccoid zoospores. DIAGNOSIS: Cutaneous dermatophilosis due to Dermatophilus congolensis. CLINICAL RELEVANCE: Painful dermal lesions due to severe dermatophilosis of the dorsal skin of sheep are capable of causing postural and gait abnormalities that may be misinterpreted as signs of neurological abnormality. Such dermal lesions may be concealed by an apparently normal fleece.

Acute fibrinous pleuropneumonia and septicaemia caused by Bibersteinia trehalosi in neonatal calves in New Zealand.

Case history: In July and August 2019, 15/40, ≤48-hour-old calves became acutely ill. The calves were all born on-farm, transferred to pens soon after birth, and fed with "gold" colostrum. The hygiene, biosecurity and ventilation in the pens were poor. Of the 15 calves, 11 died or were euthanised and four calves, ≤48-hour-old, that became acutely ill later in the outbreak were treated with cefquinome, a fourth-generation cephalosporin, and recovered. Clinical findings: The affected calves presented with acute recumbency, lethargy, tachypnoea, tachycardia, increased lung sounds, inability to stand or feed, and dehydration without pyrexia. Pathological findings: Gross findings in a calf that died naturally included fibrinous pleuropneumonia, marked oedematous expansion of the interlobular septa, especially in the ventral lung lobes, fibrinous polyserositis and fibrinous polyarthritis. A second calf that was euthanised had strikingly similar lung lesions. Histologically, the pulmonary interlobular septa of both calves were prominently expanded by oedema, dilated lymphatics and the infiltration of numerous neutrophils and macrophages interspersed with small Gram-negative rod bacteria. Likewise, the visceral pleura showed fibrinopurulent inflammation with numerous small Gram-negative rods. Microbiological findings: Microbial culture and matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry identified Bibersteinia trehalosi in the lung, stifle joint and peritoneal cavity of the first calf and lung of the second. Diagnosis: B. trehalosi acute fibrinous pleuropneumonia and septicaemia. Clinical relevance: This is the first report of the clinical findings and histological lesions of B. trehalosi pleuropneumonia and septicaemia in calves in New Zealand. The pathogen is isolated with increasing frequency from cases of bovine respiratory disease in dairy cows, feedlot cattle and calves in the United Kingdom and North America. The importance of microbial culture in cases such as this with unusual lung lesions in calves <48 hours of age, cannot be over emphasised. Cefquinome was administered to all remaining heifer calves and four calves that became ill later in the outbreak recovered after cefquinome treatment.

Recovery of brodifacoum in vomitus following induction of emesis in dogs that had ingested rodenticide bait.

AIM: To assess the benefit of inducing emesis in dogs that have ingested rodenticide bait containing brodifacoum (BDF), by determining the amount of BDF in bait recovered from the vomitus relative to the estimated amount consumed. METHODS: Between 2014 and 2015 samples of vomitus from seven dogs that ingested rodenticide baits containing BDF were submitted by veterinarians in New Zealand. All seven dogs had been given apomorphine by the veterinarian and vomited within 1 hour of ingesting the bait. Some or all of the bait particles were retrieved from each sample and were analysed for concentrations of BDF using HPLC. Based on estimations of the mass of bait consumed, the concentration of BDF stated on the product label, and the estimated mass of bait in the vomitus of each dog, the amount of BDF in the vomited bait was calculated as a percentage of the amount ingested. RESULTS: For five dogs an estimation of the mass of bait ingested was provided by the submitting veterinarian. For these dogs the estimated percentage of BDF in the bait retrieved from the vomitus was between 10-77%. All dogs were well after discharge but only one dog returned for further testing. This dog had a normal prothrombin time 3 days after ingestion. CONCLUSIONS AND CLINICAL RELEVANCE: The induction of emesis within 1 hour of ingestion can be a useful tool in reducing the exposure of dogs to a toxic dose of BDF. The BDF was not fully absorbed within 1 hour of ingestion suggesting that the early induction of emesis can remove bait containing BDF before it can be fully absorbed.

Effect of a one-off sporidesmin challenge on the milk production of dairy cows.

AIMS To investigate the effects on milk yield in lactating dairy cows of a single dose of sporidesmin, and to categorise the responses based on clinical signs and differing degrees of liver damage, as assessed by activities of γ-glutamyl transferase (GGT) and post-mortem liver histopathology. METHODS Adult lactating dairy cows (n=17) were given a single intra-ruminal dose of 0.24 mg/kg of sporidesmin dissolved in ethanol and diluted in water on Day 0; an additional three cows served as untreated controls. Weekly serum samples were collected between Days -14 and 42 and analysed for activities of GGT. Milk yields were measured daily over the same period. Cows were subjected to euthanasia due to severe clinical signs (n=2) or were slaughtered at the end of the trial. Samples of livers were examined histologically and were scored for lesions on a scale from 0 (normal) to 3 (severe). Based on GGT activities and clinical observations, cows that were treated with sporidesmin were categorised as non-responders (no clinical signs and normal GGT), subclinical (elevated GGT and no clinical signs) or clinical. Outcomes were compared between these three groups and control cows using generalised additive models. RESULTS Seven cows were classified as clinical, and had median liver scores of 22 (95% CI=20.6-23.4), six were subclinical with median liver scores of 8.7 (95% CI=3.8-13.5) and four were non-responders with median liver scores of 2.5 (95% CI=1.2-4.3). Median liver scores for the three control cows were 1 (95% CI=-0.8-2.1). Activities of GGT increased in subclinical and clinical cows around Day 7. The milk yield of all cows treated with sporidesmin, including non-responder cows, started to decrease on Day 1, and reached a nadir (a drop of between 9 and 85%) on Day 7. CONCLUSIONS AND CLINICAL RELEVANCE It is likely that the overall effects of sporidesmin consumption on milk production by the national herd in New Zealand are hugely underestimated, especially considering its effects on non-responder and subclinical cows as shown in this trial. In view of the results presented here, the authors are suggesting a change to the definition of response to sporidesmin from non-responder, subclinical, and clinical, to subclinical-low, subclinical-high, and clinical, when measuring a combination of GGT activities, clinical signs and milk yields during facial eczema-risk seasons (summer-autumn).

Bile duct lesions associated with turnip (Brassica rapa) photosensitization compared with those due to sporidesmin toxicosis in dairy cows.

Cattle grazing turnips or other brassica forage crops occasionally develop hepatogenous photosensitization. In New Zealand, cases of bovine photosensitization associated with such crops frequently occur during late summer and fall, and this coincides with the facial eczema (sporidesmin toxicosis) "season." Clinical chemistry findings in acute photosensitization cases associated with both brassica and facial eczema include marked serum elevations in γ-glutamyl transferase and glutamate dehydrogenase activities. Distinctive bile duct lesions of "subacute" turnip photosensitization in 2 cows, comprising microscopic cholangiectasis with concentric periductal fibrosis of small bile ducts, and a spectrum of changes from bile duct necrosis progressing to obliterative sclerosis are described. These bile duct lesions are compared with those in 3 cases of "subacute" facial eczema in adult cows, where medium-sized and larger ducts tend to be involved and bile duct hyperplasia and portal fibrosis are more prominent, often leading to bridging between neighboring portal triads.

Liver biopsy histopathology for diagnosis of Johne's disease in sheep.

Sheep with Johne's disease develop epithelioid macrophage microgranulomas, specific to Mycobacterium avium subsp. paratuberculosis (Map) infection, in the terminal ileum, mesenteric lymph nodes, and organs distant to the alimentary tract such as the liver. The objectives of this study were to determine whether liver pathology was present in ewes affected by Map and whether liver cores provide adequate tissue for this potential diagnostic marker. One hundred and twenty-six adult, low body condition ewes were euthanized, necropsied, and underwent simulated liver biopsy. Ileal lesions typical of Map were found in 60 ewes. Hepatic epithelioid microgranulomas were observed in all ewes with Type 3b (n = 40) and 82% (n = 11) with Type 3c ileal lesions. None were found in ewes unaffected by Map or with Type 1, 2, or 3a ileal lesions. Liver biopsy core samples provided adequate tissue for histopathology with a sensitivity and specificity of 96% (95% confidence interval [CI], 0.87-0.99) and 100% (95% CI, 0.95-1), respectively for detection of types 3b and 3c ileal lesions.

Effect of tissue processing on assessment of endoscopic intestinal biopsies in dogs and cats.

BACKGROUND: Prior studies failed to detect significant association between hypoalbuminemia and small intestinal lesions. HYPOTHESIS: Use of pictorial templates will enhance consistency of interpathologist interpretation and identification of intestinal lesions associated with hypoalbuminemia. ANIMALS: Tissues from 62 dogs and 25 cats examined as clinical cases at 7 referral veterinary practices in 4 countries. METHODS: Retrospective, observational study. Histopathology slides from sequential cases undergoing endoscopic biopsy were examined by 4 pathologists by pictorial templates. Changes for 9 microscopic features were recorded as normal, mild, moderate or severe, and 2- and 4-point scales were tested for consistency of interpretation. Logistic regression models determined odds ratios (OR) of histologic lesions being associated with hypoalbuminemia while kappa statistics determined agreement between pathologists on histologic lesions. RESULTS: There was poor agreement (kappa = -0.013 to 0.3) between pathologists, and institution of origin of slides had effect (kappa = 1.0 for 3 of 4 lesions on slides from Institution 5) on agreement between pathologists on selected histologic features. Using 2 point as opposed to 4-point grading scale increased agreement between pathologists (maximum kappa = 0.69 using 4-point scale versus maximum kappa = 1.0 using 2-point scale). Significant association (P = .019- .04; 95% OR = 3.14-10.84) between lacteal dilation and hypoalbuminemia was found by 3 pathologists. CONCLUSIONS AND CLINICAL IMPORTANCE: Substantial inconsistency between pathologists remains despite use of pictorial template because of differences in slide processing. Distinguishing between mild and moderate lesions might be important source of the disagreement among pathologists.

Effect of sample quality on the sensitivity of endoscopic biopsy for detecting gastric and duodenal lesions in dogs and cats.

BACKGROUND: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown. HYPOTHESIS: The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens. ANIMALS: Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries. METHODS: Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined. RESULTS: Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample. CONCLUSIONS AND CLINICAL IMPORTANCE: The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues.

White snakeroot poisoning in goats: Variations in toxicity with different plant chemotypes.

Tremetone and possibly other benzofuran ketones are believed to be the toxic compounds in white snakeroot. However, disease has not been reproduced with purified toxins and the concentrations of the benzofuran ketones in white snakeroot populations that cause toxicosis have not been documented. The objectives of this study were to compare the toxicity of seven plant populations, better characterize the clinical and pathologic changes of poisoning, and correlate intoxication with benzofuran ketone content. Four of the seven white snakeroot collections were toxic at the dose and duration used in the study. Affected goats became exercise intolerant, had significant serum enzyme changes and histological lesions in the large appendicular muscles. The incidence and severity of poisoning was not correlated with total doses of tremetone or total benzofuran ketone concentrations suggesting they may not be closely involved in producing toxicity and the possible involvement of an unidentified toxin. The results also demonstrate that white snakeroot populations vary chemically and toxicologically.

Infection of sheep with adult and larval Ostertagia circumcincta: abomasal morphology.

The infection of parasite-naive sheep with approximately 15,000 adult Ostertagia circumcincta via abomasal cannulae resulted in marked changes in the structure and function of the abomasum. The functional changes, which have been characterised previously, included elevated abomasal pH and increased serum concentrations of pepsinogen and gastrin. Eight days after the transplant of adult worms, the abomasa of recipient animals were significantly heavier than those of controls (P < 0.001), the thickness of the fundic mucosa was greater (P < 0.01), there were fewer parietal cells (P < 0.01) and increases in the numbers of mitotic figures and mucus-producing cells. Mucous cell hyperplasia was also evident in the fundic mucosae of sheep receiving a trickle infection of infective, third-stage O. circumcincta larvae and was prominent within nodules associated with larval development. In non-nodular mucosa, there was hyperplasia of mucous cells and changes in the distribution of parietal cells. Decreases in the number of parietal cells at the gland base were offset by increases at a mid-gland level, probably due to chronic hypergastrinaemia, so that, overall, total parietal cell number was unaffected. Mucous cell hyperplasia and the diminution of parietal cell number are seen in a diverse range of disease states and may be mediated by host growth factors such as Transforming growth factor-alpha. Alternatively, the cellular and/or the secretory changes in response to the presence of adult worms are mediated by chemicals that are cytotoxic/inhibitory for parietal cells, and released by the parasites themselves.

Solitary cervical intra- and extramedullary schwannoma.

A case of solitary cervical intramedullary schwannoma with an extramedullary extension is reported. This case demonstrates the difficulty of radiologic diagnosis of these tumours and the necessity for pre-treatment biopsy.

Food sensitivity in cats with chronic idiopathic gastrointestinal problems.

The objectives of this study were to investigate the prevalence of food sensitivity in cats with chronic idiopathic gastrointestinal problems, to identify the food ingredients responsible, and to characterize the clinical features. Seventy cats that presented for chronic gastrointestinal signs underwent diagnostic investigation. Fifty-five cats had idiopathic problems and were entered into the study. Diagnosis of food sensitivity was made by dietary elimination-challenge studies by using commercial selected-protein diets as the elimination diet. Sixteen (29%) of the 55 cats with chronic idiopathic gastrointestinal problems were diagnosed as food sensitive. The clinical signs of another 11 cats (20%) resolved on the elimination diet but did not recur after challenge with their previous diet. The foods or food ingredients responsible for the clinical signs were dietary staples. Fifty percent of affected cats were sensitive to more than 1 food ingredient. The clinical feature most suggestive of food sensitivity was concurrent occurrence of gastrointestinal and dermatological signs. Weight loss occurred in 11 of the affected cats, and large-bowel diarrhea was more common than small-bowel diarrhea. Assay of serum antigen-specific immunoglobulin E (IgE) had limited value as a screening test, and gastroscopic food sensitivity testing was not helpful. In conclusion, adverse reactions to dietary staples were common in this population of cats, and they responded well to selected-protein diets. Diagnosis requires dietary elimination-challenge trials and cannot be made on the basis of clinical signs, routine clinicopathological data, serum antigen-specific IgE assay, gastroscopic food sensitivity testing, or gastrointestinal biopsy.

The immune response in a dog to Encephalitozoon cuniculi infection.

The immune response to Encephalitozoon cuniculi infection in a dog was investigated by means of the indirect fluorescent antibody test, the leucocyte migration inhibition test and the radial immunodiffusion test for serum IgG and IgM levels. Specific antibodies were detected within 7 days of infection and they persisted for 370 days. A cell-mediated immune response was detected from Day 13 following infection until Day 97. Histopathological examination showed plasma cell infiltration of the kidneys, meninges, lung, bladder, smooth muscle and spleen.

Ovine hepatogenous photosensitivity caused by the plant Nidorella foetida (Thunb.) DC. (Asteraceae).

Following a field outbreak of hepatogenous photosensitivity in sheep, an identical condition was reproduced experimentally by dosing 2 sheep with green, homogenized, Nidorella foetida material, collected from the camp where the outbreak occurred. This is a rare, unpalatable, aromatic shrub found in swampy places in the south-western Cape Province. The main lesion was a hepatosis, characterized by peripheral coagulative necrosis and midzonal degeneration in the 2 acute cases and mild bile duct proliferation and hepatic regeneration in the more chronic field case. Botanical, toxicological, clinical and pathological data are given.

An experimental mycotoxicosis in sheep and goats caused by Drechslera campanulata, a fungal pathogen of green oats.

Field outbreaks of a syndrome of unknown aetiology associated with the grazing of green oats (Avena sativa) in the south-western Cape Province were characterized by diarrhoea, photosensitivity and death in goats and by diarrhoea and a reduction in milk production in cows. A phytopathogenic fungus, Drechslera campanulata, was isolated from conspicuous reddish-brown leaf spots on oat plants collected from both outbreaks. Pure cultures on autoclaved maize of D. campanulata isolates from oat leaves implicated in both field outbreaks, as well as a Canadian isolate, proved to be highly toxic to ducklings, goats and sheep. Characteristic clinical signs of the fatal mycotoxicosis caused by D. campanulata culture material in goats and sheep were anorexia, apathy, diarrhoea and ruminal stasis. Photosensitivity, however, was not induced. Necrosis of the forestomach mucosa was the most characteristic gross pathological change. Histopathological findings included mild focal erosions to severe, diffuse, coagulative necrosis of the mucosa in the rumen, reticulum and omasum and congestion and haemorrhages in the abomasum. These results provide circumstantial evidence that green oat leaves infected by D. campanulata may cause outbreaks of a mycotoxicosis in grazing animals.

The pathology of chronic Drechslera campanulata toxicosis in inbred rats.

Cultures on autoclaved maize of the phytopathogenic fungus, Drechslera campanulata, were incorporated into diets and fed to male inbred BDIX rats. In a pilot trial, a diet containing 30% D. campanulata culture material killed 5 out of 5 rats in 15-25 days. Lesions included gastric corpus erosions, gastrorrhagia and ulcerative typhlitis. Diets containing 5% or 10% culture material induced erosive to ulcerative typhlitis and oedema and hyperplasia of the ileocaecal lymph nodes in 40 out of 40 rats. Other changes included: mass loss; normocytic, hyperchromic anaemia; leukocytosis with neutrophilia; reductions in plasma proteins, creatinine, calcium and cholesterol; elevated serum enzymes; hepatosis, nephrosis and mycoplasma-like interstitial pneumonia. No lesions were present in control rats, and their profiles were normal. Ulcerative typhlitis induced by D. campanulata in rats resembles that seen in chronic piperonyl butoxide intoxication as well as that due to single treatments of indomethacid, although small intestinal ulcers are more frequent in the latter. Overgrowth of intestinal flora may be involved in ulcer pathogenesis. The pathology of drechsleratoxicosis in rats is compared to that in sheep and goats where necrotic lesions in the forestomach and, to a lesser extent, in the caecum are characteristic findings.