Newborn foals of mares grazing on Acremonium coenophialum-infected fescue pasture throughout gestation or from gestation day 300 to parturition had increased gestation duration and decreased serum triiodothyronine concentration. Pregnant mares were allotted to 4 treatments: grazing continuously on endophyte-free (E-) fescue, grazing continuously on endophyte-infected (E+) fescue, grazing on E+ fescue from gestation day 300 to parturition, and grazing on E+ fescue from conception to gestation day 300. Morphometric studies indicated that foals born to mares exposed to endophyte late in gestation had large, distended thyroid follicles lined by flat cuboidal epithelial cells. Mean triiodothyronine concentration in foals exposed to endophyte (395.2 ng/dl) was decreased (P < 0.01), compared with mean values in control foals (778.0 ng/dl). Thyroxine and reverse triiodothyronine concentrations were not significantly different among groups. Foal organ weight as a percentage of foal body weight was not significantly different among experimental groups.

Vestibulotoxic and ototoxic effects often are seen after long-term, high-dose systemic treatment with gentamicin, but toxic effects after topical use have not been reported in animals, to the authors' knowledge. Vestibular and auditory effects of twice daily otic gentamicin treatment for 21 days were evaluated in 10 dogs with intact tympanic membranes and in the same 10 dogs after experimental bilateral myringotomy. Each dog served as its own control; 7 drops of gentamicin sulfate (3 mg/ml in a buffered aqueous vehicle) were placed in 1 ear, and 7 drops of vehicle were placed in the opposite ear. Treatment and control ears were reversed after myringotomy. Vestibular function was evaluated daily by neurologic examination and behavioral assessment Auditory function was evaluated twice weekly by determination of brain stem auditory evoked potentials. Gentamicin sulfate placed in the ear of clinically normal dogs with intact or ruptured tympanic membranes, in the quantities used in this study, did not induce detectable alteration of cochlear or vestibular function. Serum gentamicin concentration after 21 days of treatment was detectable in only 2 dogs and was an order of magnitude below documented toxic concentrations.

Whereas the clinical efficacy of vaccination against pseudorabies has been studied extensively, methods to evaluate the influence of vaccination on pseudorabies virus (PRV) transmission have only recently become available. In this study, PRV transmission and growth performance in finishing pigs vaccinated either once or twice were compared. The incidence of PRV infections was significantly (P = 0.039) higher in the group vaccinated once (38%) than in the group vaccinated twice (10%). The reproduction ratio R, which is defined as the average number of new infections caused by 1 infectious individual, was estimated in both groups. This ratio was also significantly (P = 0.025) higher among single vaccinated pigs (R = 3.4) than among pigs that had received double vaccination (R = 1.5). In compartments where serologic evidence of PRV introduction was observed, the mean daily weight gain was significantly (P = 0.029) lower in pigs vaccinated once (698 g/d) than in pigs vaccinated twice (721 g/d). Results of this study document the possibility to objectively evaluate the effect of vaccination on PRV transmission under field conditions. From the results, we concluded that double vaccination is advantageous in populations of finishing pigs at risk for PRV introduction. However, even among pigs vaccinated twice, extensive spread of PRV can occur.

Adrenocortical function was assessed in 27 Beagle pups at 2, 4, 6, 8, 10, and 12 weeks of age by determination of plasma sodium, potassium, and chloride concentrations; serum aldosterone and cortisol concentrations; and plasma ACTH concentrations. Serum cortisol concentration was measured before and 1 and 2 hours after IM administration of 2.2 IU of ACTH/kg of body weight. Serum progesterone concentration also was determined for all pups at 2, 4, and 6 weeks of age. Mean baseline cortisol concentration was lower for pups 8 weeks old or younger than for mature dogs. Nevertheless, mean serum ACTH-stimulated cortisol concentration in dogs of all age groups increased into the adult reference range after administration of ACTH. For pups 4 weeks old or younger, increase in cortisol concentration was maximal at 2 hours after ACTH administration. However, in pups between 6 and 12 weeks of age, the increase in cortisol concentration was maximal 1 hour after ACTH administration in about a third of the pups, whereas the remaining pups had peak values at 2 hours. Mean plasma sodium, potassium, and chloride concentrations for each age group were within the reference ranges established for mature dogs, with the exception of lower mean plasma sodium and chloride concentrations in pups 4 weeks old or younger. Mean serum aldosterone concentration in pups of each age group was substantially higher than the range of aldosterone concentrations for clinically normal mature dogs. Median progesterone concentration was uniformly less than 0.2 ng/ml for all pups 6 weeks old or younger. The normal endogenous ACTH concentration and adequate cortisol responses to exogenous ACTH seen in our pups would support functional pituitary gland and adrenal cortex for cortisol production. The low baseline cortisol concentration observed in the pups of this study may be related to reduced binding of cortisol to plasma proteins, as exists in human infants. The hyponatremia and increased aldosterone concentration may be explained by reduced renal tubular response to aldosterone, as also evidenced in the human infant kidney.

Indices of renal function and damage were measured in 12 healthy male adult llamas fed a diet of mixed alfalfa/grass hay (mixed hay) and water ad libitum. Using a collection bag fitted over the preputial area, urine samples were collected at 6, 12, and 24 hours. Serum samples were obtained concurrently to determine endogenous creatinine clearance (CL), total (TE) and fractional excretion (FE) of electrolytes (Na, K, Cl, P), electrolyte CL, urine and serum osmolality, urine enzyme activities (gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase), and urine protein concentration. Urine production was quantified. Three months later, 10 of the 12 llamas were fed a grass hay diet and water ad libitum. Similar samples were obtained, and similar measurements were made. Urine production was higher when the llamas were fed the mixed hay diet. Total urine volume for llamas fed mixed hay ranged from 628 to 1,760 ml/24 h, with a median of 1,307.5 ml/24 h, compared with a range of 620 to 1,380 ml/24 h and a median of 927.50 ml/24 h for llamas fed grass hay. Median urine osmolality was higher in llamas fed mixed hay (1,906 mOsm/kg of body weight, with a range of 1,237 to 2,529 mOsm/kg), compared with llamas fed grass hay (1,666 mOsm/kg with a range of 1,163 to 2,044 mOsm/kg). Creatinine CL did not vary significantly over time for either diet. Median creatinine CL was higher for llamas fed mixed hay, compared with llamas fed grass hay--0.78 ml/min/kg with a range of 0.20 to 1.83 ml/min/kg vs 0.45 ml/min/kg with a range of 0.13 to 3.17 ml/min/kg. Clearances for K and Cl varied significantly among the periods. However, median CL for Na and P did not vary over time for either diet. Overall values for these electrolytes in llamas fed mixed hay and grass hay diets were: CL(Na), 0.001 and 0.002 ml/min/kg and CL(P), 0.0006 and 0.0004 ml/min/kg respectively. The FE rates of K, Cl, and P did not vary significantly over time for either diet. Median respective FE for these electrolytes in the llamas fed mixed hay and grass hay diets include: FE(K), 84.90 and 63.10%; FE(Cl), 0.85 and 1.30%; and FE(P), 0.10 and 0.10%. Fractional excretion of Na varied over time for both diets and could not be expressed accurately as an overall median. Median respective TE of electrolytes for llamas fed the mixed hay and grass hay diets were: TE(Na), 0.007 and 0.03 mEq/kg/h; TE(Cl), 0.04 and 0.06 mEq/kg/h; and TE(P), 0.0002 and 0.00 mg/kg/h; TE(K) varied significantly (P < 0.05) over time for both diets. Urine gamma-glutamyltransferase activity changed significantly (P < 0.05) over time. Urine N-acetyl-beta-D-glucosaminidase activity was influenced by an interaction between diet and time. Median urine protein concentration was 26.0 mg/dl, with a range of 11.0 to 73.0 mg/dl for llamas fed mixed hay, and was 28.0 mg/dl, with a range of 16.0 to 124.0 mg/dl for llamas fed grass hay.

Urine activity product ratios of uric acid, sodium urate, and ammonium urate and urinary excretion of metabolites were determined in 24-hour samples produced by 6 healthy Beagles during periods of consumption of a low-protein, casein-based diet (diet A) and a high-protein, meat-based diet(diet B). Comparison of effects of diet A with those of diet B revealed: significantly lower activity product ratios of uric acid (P = 0.025), sodium urate (P = 0.045), and ammonium urate (P = 0.0045); significantly lower 24-hour urinary excretion of uric acid (P = 0.002), ammonia (P = 0.0002), sodium (P = 0.01), calcium (P = 0.005), phosphorus (P = 0.0003), magnesium (P = 0.01), and oxalic acid (P = 0.004); significantly (P = 0.0001) higher 24-hour urine pH; and significantly (P = 0.01) lower endogenous creatinine clearance. These results suggest that consumption of diet A minimizes changes in urine that predispose dogs to uric acid, sodium urate, and ammonium urate urolithiasis.

Activities of diagnostically important enzymes were measured in serum and lysates of liver, kidney, skeletal muscle, heart, intestine, lung, and pancreatic tissues from wild-caught yellow rat snakes, Elaphe obsoleta quadrivitatta. All samples were analyzed for alkaline phosphatase, lactate dehydrogenase (LD), aspartate transaminase (AST), alanine transaminase, gamma-glutamyltransferase, and creatine kinase (CK) activities. The major enzyme activities found in the liver were LD and AST. The kidney had moderate activities of LD, AST, alanine transaminase, and CK. Skeletal muscle and heart contained high CK activity. Intestine, lung, and pancreas had low activities for most enzymes analyzed. Little to no gamma-glutamyltransferase activity was found in serum or tissues analyzed. Serum enzyme activities in yellow rat snakes were similar to those described for other reptile species, except for serum CK activity, which was increased in rat snakes.

Heart and body weights were obtained from 230 Greyhounds during necropsy. Sex and age were recorded for each Greyhound. Twenty-nine racing and 21 nonracing Greyhounds among the 230 dogs were compared. Heart-to-body weight ratio was calculated. Statistical analysis was done to determine the effects of age, sex, and racing on heart and body weights and heart-to-body weight ratio. In adult Greyhounds, mean +/- SD body weight was 28.4 +/- 3.1 and 31.5 +/- 2.8 kg, heart weight was 355.6 +/- 52.8 and 381.4 + /-50.8 g, and heart-to-body weight ratio was 1.3 +/- 0.2 and 1.2 +/- 0.2% for females and males, respectively. Heart and body weights were significantly different between sex and age groups and among nonracing and racing males. However, heart-to-body weight ratio was not significantly different among age, sex, or racing groups.

The concentration of carbonic anhydrase III isoenzyme (cA-III) in serum samples from 216 clinically normal Thoroughbreds was determined by use of an enzyme immunoassay. The concentration range of cA-III was from 16.0 to 254.5 ng/ml (mean, 56.5 +/- 11.9 ng/ml). Significant differences were not detected according to age or sex. To confirm whether serum cA-III concentration was high in horses with muscle disease, serum samples of 11 horses with exertional rhabdomyolysis were analyzed by enzyme immunoassay. Their serum cA-III concentration was about 56 times (3,136 +/- 2,610 ng/ml) that of healthy Thoroughbreds. Concentration of cA-III was higher in horses with rhabdomyolysis that had been transiently recumbent than in horses with mild disease that were reluctant to move. Blood samples obtained serially from 6 horses with exertional rhabdomyolysis were studied. Serum activities of aldolase, creatine kinase, aspartate transaminase, and lactate dehydrogenase were high. Increases and decreases in concentration of cA-III were more rapid than that for aldolase, creatine kinase, aspartate transaminase, and lactate dehydrogenase activities; thus, cA-III may be clinically applicable as a diagnostic marker for muscle disease in horses.

Serum alpha-mannosidase activity and swainsonine concentration were determined in 4 cattle and 15 sheep (3 groups of 5 each) that were administered ground locoweed (Oxytropis sericea or Astragalus lentiginosus) containing swainsonine at dosages of approximately 0.8 mg/kg of body weight/d (cows, 30 days each) and 0, 1.0, and 1.5 mg/kg/d (sheep, 11 days each). The cattle developed mild clinical signs of locoism, including signs of depression, lethargy, and slight intention tremors. Clinical signs of toxicosis were not observed in the sheep. Within 24 hours of initial treatment, serum alpha-mannosidase activity in cows and sheep, measured by the release of 4-methylumbelliferone from an artificial substrate, was markedly decreased to 28 and 40 micromoles of 4-methylumbelliferone/L, respectively. Mean serum alpha-mannosidase activity of control cows and sheep was 400 +/- 94 and 422 +/- 42 (mean +/- SD), respectively. In the treated animals, decreased serum alpha-mannosidase activities returned to normal or higher activities within 6 days after treatment was discontinued. Using a jack bean alpha-mannosidase assay, increased swainsonine activity (153, 209, and 381 ng/ml, respectively) was detected in the serum of cattle and of sheep in the high- and low-dose groups within 24 hours after treatment with locoweed. Swainsonine concentration remained high, with mean concentrations of 204, 432, and 395 ng/ml (cows and 2 sheep groups, respectively) during the treatment period. After treatment, swainsonine was rapidly cleared, with estimated serum half-life of 16.4, 17.6, and 20.3 hours (cows, and high- and low-dose sheep groups, respectively). Significant differences in either alpha-mannosidase activity or swainsonine concentration were not detected between the 2 groups of treated sheep. These results suggest that serum alpha-mannosidase and swainsonine values are sensitive indicators of locoweed intoxication in cattle and sheep. Furthermore, it suggests that swainsonine is rapidly absorbed, resulting in rapid inhibition of serum alpha-mannosidase activity, leading to high serum swainsonine concentration. After exposure is eliminated, swainsonine is rapidly cleared from the serum, with serum alpha-mannosidase activity returning to normal values shortly thereafter.