Leonardo Frasson dos Reis

Hepatogenous photosensitization associated with liver copper accumulation in buffalos

Four 1.5-year-old, male, Murrah buffalos were maintained during eight months without direct solar exposure during a study of copper toxicosis. Four days after solar exposure, all buffalos presented clinical manifestations consistent with acute photosensitization, including anorexia, apathy, loss of body weight, and generalized cutaneous lesions. Gross lesions were characterized by severe erythema, localized edema, fissures, tissue necrosis, gangrene and crust formation with serous exudation. Liver copper concentration was evaluated, and cutaneous biopsies were taken when clinical signs were evident. The liver copper concentration before solar exposure was increased in all animals. Histopathologic examination of the skin revealed hepatogenous photosensitization characterized by parakeratotic hyperkeratosis, acantholysis, degeneration of squamous epithelial cells, epidermal necrosis with atrophy of sweat glands, and multifocal superficial and deep dermal edema. These findings suggest that asymptomatic accumulation of copper within the liver might have induced hepatic insufficiency thereby resulting in secondary photosensitization when these buffalos were exposed to sunlight.

Biópsia hepática por laparotomia paracostal em bovinos e búfalos

Liver biopsy in ruminants is an important technique for clinical diagnosis of toxic and metabolic diseases, especially mineral disorders. The most frequent procedures used so far results in an small amount of liver and not enough for multiple tests. The present study aims to evaluate the efficacy of paracostal laparotomy liver biopsy technique in cattle and buffalo and to follow possible changes on biochemical and hematological profiles caused by the surgery. Ten cattle and ten buffalo were used in this study. The animals were kept on their normal position and sedated with xilazin and locally infiltrated with lidocain and epinefrin. The access to abdominal cavity was carried through a right paracoastal laparotomy, ventrally to the transverse process of 2nd or 3rd lombar vertebra. A small portion of the hepatic caudal lobe (2 to 4g) was clinched by a Doyen clamp and removed. The abdominal cavity was closed as normally routine. Blood samples were taken to biochemical tests and hemogram before the procedure, and 24h, 48h, 5 and 10 days later. The technique was practical and easy to be performed (took approximately 25 minutes). The technique described here was efficient and offers low risk to animal health and provided enough amount of liver tissue for multiple tests.

Comparison of Rumen Fluid pH by Continuous Telemetry System and Bench pH Meter in Sheep with Different Ranges of Ruminal pH

We aimed to compare the measurements of sheep ruminal pH using a continuous telemetry system or a bench pH meter using sheep with different degrees of ruminal pH. Ruminal lactic acidosis was induced in nine adult crossbred Santa Ines sheep by the administration of 15 g of sucrose per kg/BW. Samples of rumen fluid were collected at the baseline, before the induction of acidosis (T 0) and at six, 12, 18, 24, 48, and 72 hours after the induction for pH measurement using a bench pH meter. During this 72-hour period, all animals had electrodes for the continuous measurement of pH. The results were compared using the Bland-Altman analysis of agreement, Pearson coefficients of correlation and determination, and paired analysis of variance with Students t-test. The measurement methods presented a strong correlation (r = 0.94, P < 0.05) but the rumen pH that was measured continuously using a telemetry system resulted in lower values than the bench pH meter (overall mean of 5.38 and 5.48, resp., P = 0.0001). The telemetry system was able to detect smaller changes in rumen fluid pH and was more accurate in diagnosing both subacute ruminal lactic acidosis and acute ruminal lactic acidosis in sheep.