This experimental study was carried out in the faculty of veterinary medicine, at Suez Canal University, Ismailia, Egypt. A total of 40 dogs were categorized based on the severity of dehydration into three categories (mild, moderate, and severe) and a fourth group for dogs without dehydration. Many biochemical parameters were utilized to evaluate dehydration, including blood electrolytes (Na, K, CL, Ca, Mg, and Ph), liver enzymes (ALT and AST), kidney function parameters (urea, creatinine, and uric acid), and lactate. The most prevalent clinical manifestations of gastroenteritis in dogs were vomiting, followed by profuse watery yellowish to bloody diarrhea, anorexia, and mild, moderate, and severe degrees of dehydration manifested by STT retardation. Four OLR models ranging from univariable to multivariable logistic regression were developed. Lactate, AST, creatinine, urea, and uric acid were recorded as positive predictors for the severity of dehydration; however, only lactate, AST, and uric acid were recorded as positive significant (p<0.05) predictors for the degree of dehydration. Na, K, Cl, Ca, Mg, Ph, and ALT were all negative predictors of dehydration level. Na and K were significant (P0.05) negative predictors of the degree of dehydration, whereas the remaining variables were not substantially related to the degree of dehydration. It was observed that biochemical markers are good indicators of dehydration; including these factors in the OLR model will help in differentiating between different degrees of dehydration.

Clinically normal dogs were evaluated in states of dehydration, euhydration, and after fluid administration to determine effects of hydration state on renal clearance values. Endogenous creatinine, exogenous creatinine, and [(14)C]inulin clearances, were determined to measure glomerular filtration rate (GFR); in some experiments p-aminohippurate clearance was determined to measure renal plasma flow. Dehydration caused significant (P < 0.05) decrease in clearance values, compared with euhydration, and clearance values during euhydration were significantly (P < 0.05) less than values obtained after a single gavage with water (30 ml/kg of body weight). Sustained administration of 3 fluid regimens was evaluated for effects on clearance values (treatment A = 30 ml of lactated Ringer's solution/kg/h; treatment B = 30 ml of water/kg by gavage hourly; treatment C = 10 ml of glucose:lactated Ringer's solution/ kg/h). All regimens of fluid therapy caused significant P < 0.05), progressive increases in GFR, but treatment C resulted in the most stable GFR values. Increases in clearance values were associated with positive fluid balance; the rate of fluid administration was greater than the rate of urine formation. Data from 285 GFR determinations on 85 dogs were evaluated retrospectively. For each determination, three 20-minute urine collections were made beginning 40 minutes after 30 mi of water/kg was given by gavage. Values between collections were significantly (P < 0.05) different, but varied by < 3%. Comparison of methods for measurement of GFR indicated that endogenous creatinine clearance and [14)C]inulin clearance were highly correlated (R(2) = 0.82), but mean clearance values were markedly different (mean +/- SEM, 28.70 +/- 0.01 and 37.07 +/- 1.29 ml/min, respectively). Exogenous creatinine clearance and [(14)C]inulin clearance were highly correlated (R(2) = 0.95), and mean values were 40.54 +/- 0.70 and 41.02 +/- 0.70 ml/min respectively. We conclude that: state of hydration has a marked effect on GFR; rate of fluid administration that exceeds rate of urine production results in progressive increases in GFR; a single water gavage of 30 ml/kg gives stable GFR values for three 20-minute collection periods, may avoid subclinical states of dehydration, and facilitates accurate urine collections; and endogenous creatinine clearance, as conducted in this study, does not accurately measure GFR.

Cryptosporidium spp. was detected in 3 cows from rectal pinch&#xD;samples. Direct smear stained with Acid Fast and Kinyoun stain was used to detect the organism. Subsequent samplings also indicated positive for Cryptosporidiosis, whereby one of the animals died due to dehydration and severe clinical signs of diarrhea. The farm had contaminated water supply where two out of the four ponds were&#xD;positive for Cryptosporidium spp. whereas the municipal water supply was negative. The management of the farm was poor in terms of nutrition and cleanliness which led to Cryptosporidium spp. infection in the cattle compounded by stress factors. The mortality of the adult dairy cattle and calves was also high reaching up to&#xD;40%. The most common cause of death was leg weakness, severe dehydration and pneumonia in calves as a result of severe infections. Cryptosporidiosis is zoonotic and thus needs to be controlled to prevent outbreaks in the human population.