Five cows in the last month of gestation, provided with uterine electrodes and in which catheters had been chronically installed in the fetal aorta, were used to study patterns of fetal heart rate (FHR) and the influence of periods of myometrial electrical activity during gestation (contractures) on FHR. The FHR was calculated by counting the number of blood pressure pulses on the tracings during alternate periods of 12 seconds. Three 1-hour recordings without contractures and 10 recordings during the time of a contracture were randomly selected for each cow. The calculated data points were plotted on a graph to display FHR patterns. In 41 periods associated with single contractures, FHR data points were taken every 72 seconds. Changes in absolute and relative FHR in these periods were determined to analyze a possible effect of contractures on FHR. Three types of variation in FHR patterns could be distinguished: a short-term, low-amplitude variation of basal FHR; a second type in which the duration was < 4 minutes and the amplitude was greater than or equal to 15 beats/min; and prolonged periods with increased or decreased FHR values (> 4 minutes and greater than or equal to 15 beats/min). The relationship between these types of variation and fetal activity states remains to be established for cows. During the 60 hours of recordings that were analyzed, a period of several minutes during which FHR values were extremely high (> 180 beats/min) was found 3 times. There were no significant differences in absolute or relative FHR before, during, or after a contracture.

An agar gel immunodiffusion (AGID) test was used over a 3-year period to examine 1,871 serum samples from sheep representing 5 Mycobacterium paratuberculosis infected flocks and 4 flocks presumed to be uninfected. Of 1,032 sheep, 31 had positive AGID test results (scoring 1 to 5), and 23 of these 31 were ecropsied. Infection with M paratuberculosis was confirmed by 1 or more of the following findings: observation of typical lesions on histologic examination of sections of ileum or ileocecal lymph nodes, observation of clumps of acid-fast bacteria in mucosal smears of ileum, and isolation of the organism from feces or tissue. False-positive results on AGID testing were not found in sheep from flocks known to have exposure to Cotynebacterium pseudotuberculosis. Diarrhea in infected sheep was observed infrequency; chronic, severe weight loss was the most common sign observed. On histologic examination of tissues from 20 infected sheep, 16 (80%) had diffuse lesions of the ileum and 13 (65%) had acid-fast bacteria in areas of ileal inflammation; 4 had discrete granulomas and peripheral lymphocytic infiltrates in the ileum. Sheep with diffuse lesions tended to have higher mean scores on AGID testing and examination for acid-fast bacteria, compared with those from sheep with more discrete lesions. Bacteriologic culture yielded M paratuberculosis from only 3 sheep with paratuberculosis. On the basis of results of this study, we suggest that the nature of the response to infection with M paratuberculosis may influence the results of diagnostic tests for paratuberculosis, and that AGID testing may be useful to identify M paratuberculosis infection in sheep with chronic weight loss and in flock-screening programs.

After IV administration of 0.5 mg of glucagon/cat, glucose tolerance and insulin secretory response were evaluated in 10 lean cats, 10 obese cats, and 30 cats with diabetes mellitus. Blood samples for glucose and insulin determinations were collected immediately before and at 5, 10, 15, 30, 45, and 60 minutes after IV administration of glucagon. Baseline serum insulin concentration and insulin secretory response were used to classify diabetes mellitus in the 30 cats as type I or type II. Mean (+/- SEM) baseline and 30-minute serum glucose concentrations in obese cats were significantly (P < 0.05) decreased, compared with values in lean cats, but were similar at all other blood sample collection times. Serum glucose concentration in diabetic cats was significantly (P < 0.05) greater than values in obese and lean cats at all blood sample collection times. Two statistically different insulin responses to IV administration of glucagon were seen in diabetic cats. Of the 30 diabetic cats, 23 had minimal insulin secretory response after glucagon administration (ie, serum insulin concentration was at or below sensitivity of the insulin assay). Seven diabetic cats had baseline serum insulin concentration similar to that of obese cats and significantly (P < 0.05) greater than that of lean cats and of the other 23 diabetic cats. In these 7 diabetic cats, serum insulin concentration increased after glucagon administration. Total insulin secretion was not significantly different between these 7 diabetic cats and the lean and obese cats, and was significantly (P < 0.05) greater than total insulin secretion in the other 23 diabetic cats. Results support existence of type-I and type-II diabetes mellitus in cats.

Desoxycorticosterone pivalate was administered IM to juvenile Beagles at 0, 2.2, 6.6, or 11 mg/kg of body weight daily over a consecutive 3-day period every 28 days (equivalent to a cumulative monthly dosage of 0, 6.6, 19.8, or 33 mg/kg) for 6 months. Polyuria, polydipsia, and decreases in serum potassium and BUN concentrations were detected while the dogs were being treated. Transient increases in serum sodium concentrations also were detected. The treated males had significant decreases in body weight gain, resulting in an 18% decrease in body weight in the 11-mg/kg dosage group, compared with the controls. The weights of the adrenal glands, epididymides, and testes also were lower in the treated males. Organ weights for the 2.2, 6.6, and 11-mg/kg dosage groups were: 86, 79, and 69%, respectively, of the controls (adrenal glands); 80, 70, and 68%, respectively, of the controls (epididymides); and, 79, 75, and 67%, respectively, of the controls (testes). When normalized to body weight, these decreases in organ weight were still dosage-dependent, but the differences were less remarkable. In contrast, the relative weight (to body weight) of the kidneys (males and females) and of the thyroid and parathyroid glands (males) were higher dosage-dependently. All of the treatment-related effects, other than organ and body weight changes, appeared to be reversible following the cessation of treatment. On the basis of these results, it was concluded that treatment with desoxycorticosterone pivalate could be tolerated, even when given at dosages 15-fold the therapeutic dosage of 2.2 mg/kg every 25 days.

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.

Topically applied demecarium bromide (0.125 and 0.25%) and echothiophate iodide (0.125 and 0.25%) solutions were evaluated in Beagles with normotensive eyes and Beagles with inherited glaucoma. In single-dose studies, the effects of intraocular pressure (IOP) and pupil size (PS) were measured in eyes before drug treatment and in drug- and nondrug-treated eyes. Both concentrations of the 2 drugs induced long-term miosis and decrease in IOP in normotensive eyes of Beagles and of eyes of Beagles with inherited glaucoma. Demecarium bromide (0.125 and 0.5%) decreased IOP for 49 and 55 hours, respectively. Echothiophate iodide (0.125 and 0.5%) reduced IOP for 25 and 53 hours, respectively. The miosis associated with both concentrations of the 2 drugs generally paralleled the decreases in IOP.

In an abattoir-based case-control study, histologic, and macroscopic examination of porcine intestines at slaughter and 2 molecular assays were compared for use as diagnostic tests of proliferative enteritis (PE). Fecal samples and intestinal specimens were collected from pigs with grossly thick ileum and from clinically normal pigs at slaughter. Tissue specimens were fixed in neutral buffered 10% formalin, and sectioned. Sections stained with H&E were examined for proliferative lesions by a pathologist unaware of the group to which the pig had been assigned on the basis of results of gross examination. Adjacent tissue sections, stained with Warthin-Starry (silver) stain, were examined for presence of the intracellular bacterium of PE, ileal symbiont (IS)-intracellularis, in the enterocytes of the intestinal crypts by the senior author, who was unaware either of the group to which the pig had been assigned or diagnosis by the pathologist. Bacterial DNA was extracted from the fecal samples and assayed by dot-blot hybridization and polymerase chain reaction (PCR) for presence of IS-intracellularis DNA, without knowledge of results of the other examinations. The PCR assay for IS-intracellularis was a specific and sensitive diagnostic test for PE, and dot-blot hybridization was sensitive, but was less specific. Macroscopic examination of intestines at slaughter was a sensitive, but not specific, test. Association between IS-intracellularis and proliferative lesions was statistically examined in the same study. There was a highly significant (P = 0.0078) association between presence of naturally acquired proliferative lesions and intracellular infection induced by IS-intracellularis. The odds ratio of greater than or equal to 14 and estimated attributable fraction of greater than or equal to 92% indicate that IS-intracellularis may be a necessary cause of PE.

The density of the cricoid cartilage from 29 equine larynges collected from an abattoir was determined by dual photon absorptiometry (DPA). Densities of the right and left cricoid cartilages were highly correlated. No correlation was found between age of the horse and the density of the cricoid cartilage.

We compared the plasma cortisol and immunoreactive corticotropin (IR-ACTH) responses to incremental doses (1.25, 12.5 and 125 micrograms) of synthetic ACTH (cosyntropin) administered IV to 6 clinically normal cats. Mean plasma cortisol concentration increased significantly (P < 0.0001) after administration of all 3 doses of cosyntropin. After administration of the 1.25- and 12.5-microgram doses, plasma cortisol concentration peaked at 30 minutes, then decreased to values not significantly different from baseline concentration by 90 and 120 minutes, respectively. In contrast, after administration of the 125-microgram dose, mean cortisol concentration peaked at 60 minutes and remained significantly (P < 0.05) higher than baseline values at 120 minutes. Compared with the 1.25- and 12.5-microgram doses, administration of the 125-microgram dose of cosyntropin induced significantly (P < 0.05) higher cortisol responses at 60, 90, and 120 minutes. Although individual cat's peak plasma cortisol concentration after administration of the 125-microgram dose was higher than the peak value determined after administration of the 2 lower doses of cosyntropin, these differences were not statistically significant. Mean plasma IR-ACTH concentration increased significantly (P < 0.0001) and reached a maximal value at 30 minutes after administration of all 3 doses of cosyntropin. After administration of the 1.25- and 12.5-microgram doses, plasma IR-ACTH concentration decreased to values not significantly different from baseline concentration by 60 and 120 minutes, respectively, whereas mean IR-ACTH concentration remained significantly (P < 0.05) higher than baseline values 120 minutes after administration of the 125-microgram dose. Mean peak plasma IR-ACTH concentration attained after administration of the 125-microgram dose of cosyntropin was significantly higher than that attained after administration of the 2 lower doses. Peak plasma IR-ACTH concentration attained after administration of the 12.5-microgram dose of cosyntropin was significantly higher than that attained after administration of 1.25 micrograms of cosyntropin. Results of the study indicate that IV administration of cosyntropin at doses ranging from 1.25 to 125 micrograms induces similar peak plasma cortisol responses in clinically normal cats, indicating that all of the doses may maximally stimulate the adrenal cortex. Administration of the higher cosyntropin doses did, however, result in more prolonged adrenocortical response.

Four 1-year-old steers were each inoculated orally with 10,000 Toxoplasma gondii oocysts of the GT-1 strain and euthanatized on postinoculation days (PID) 350, 539, 1191, and 1201. Samples (500 g) of tongue, heart, semimembranosus and semitendinosus muscles (roast), intercostal muscles (ribs), longismus muscles (tenderloin), brain, kidneys, liver, and small intestine were bioassayed for T. gondii by feeding to cats and examination of cat feces for shedding of oocysts. Toxoplasma gondii was recovered by bioassays in cats from the 3 steers necropsied PID 350, 539, and 1191, but not from the steer euthanatized on PID 1201. Cats shed oocysts after ingesting tongue from 2 steers, heart from 3 steers, liver from 2 steers, and roast, ribs, brain, and intestines from 1 steer each. Taxoplasma gondii was not isolated from any of the other bovine tissues. In addition to tissues bioassayed in cats, homogenates of mesenteric lymph nodes, lungs, spinal cord, spleen, and eyes were bioassayed in mice for T. gondii infection. Toxoplasma gondii was not recovered from the 135 mice inoculated with tissue from each of the 4 steers. All 4 inoculated steers developed high T. gondii antibody titers (greater than or equal to 1:8,000) in the agglutination test, using formalin-fixed whole tachyzoites. In the steer euthanatized on PID 1201, agglutinating T. gondii antibody titers decreased from 1:4,000 to 1:320 between 2 and 5 months after inoculation and to 1:20 by 19 months after inoculation.