To study behavioral and cardiopulmonary characteristics of horses recovering from inhalation anesthesia, 6 nonmedicated horses were anesthetized under laboratory conditions on 3 different days, with either halothane or isoflurane in O2. Anesthesia was maintained at constant dose (1.5 times the minimum alveolar concentration [MAC]) of halothane in O2 for 1 hour (H1), halothane in O2 for 3 hours (H3), or isoflurane in O2 for 3 hours (13). The order of exposure was set up as a pair of Latin squares to account for horse and trial effects. Circulatory (arterial blood pressure and heart rate) and respiratory (frequency, PaCO2, PaO, pHa) variables were monitored during anesthesia and for as long as possible during the recovery period. End-tidal percentage of the inhaled agent was measured every 15 seconds by automated mass spectrometry, then by hand-sampling after horses started moving. Times of recovery events, including movement of the eyelids, ears, head, and limbs, head lift, chewing, swallowing, first sternal posture and stand attempts, and the number of sternal posture and stand attempts, were recorded. The washout curve or the ET ratio (end-tidal percentage of the inhaled agent at time t to end-tidal percentage of the inhaled agent at the time the anesthesia circuit was disconnected from the tracheal tube) plotted against time was similar for HI and H3. The slower, then faster (compared with halothane groups) washout curve of isoflurane was explainable by changes in respiratory frequency as horses awakened and by lower blood/gas solubility of isoflurane. The respiratory depressant effects of isoflurane were marked and were more progressive than those for halothane at the same 1.5 MAC dose. During the first 15 minutes of recovery, respiratory frequency for group-13 horses increased significantly (P < 0.05), compared with that for the halothane groups. For all groups, arterial blood pressure increased throughout the early recovery period and heart rate remained constant. Preanesthesia temperament of horses and the inhalation agent used did not influence the time of the early recovery events (movement of eyelids, ears, head, and limbs), except for head lift. For events that occurred at anesthetic end-tidal percentage < 0.20, or when horses were awake, temperament was the only factor that significantly influenced the nature of the recovery (chewing P = 0.04, extubation P = 0.001, first stand attempt P = 0.008, and standing P = 0.005). The quality of the recoveries did not differ significantly among groups (H1, H3, I3) or horses; however 5 of 6 horses recovering from the H1 exposure had ideal recovery. During recovery, the anesthetic end-tidal percentage did not differ significantly among groups. However, when concentrations were compared on the basis of anesthetic potency (ie, MAC multiple) a significantly (P < 0.05) lower MAC multiple of isoflurane was measured for the events ear movement, limb movement, head lift, and first attempt to sternal posture, compared with that for horses given halothane, indicating that isoflurane may be a more-potent sedative than halothane in these horses.

Each of 5 US-origin serotypes of bluetongue virus (BTV) was inoculated into a separate pair of sheep. The duration of each animal's ensuing viremia was monitored, using a BTV serogroup-specific nested polymerase chain reaction (PCR) method and an embryonating chicken egg (ECE) inoculation procedure. Mean duration of viremia was 100 and 38 days for the PCR and ECE methods, respectively. This difference was significant (P < 0.001) and documents a more prolonged viremia in virus-exposed sheep than has been reported. A dual internal oligonucleotide solution hybridization procedure was developed for the rapid (2 hours) colorimetric detection and identification of BTV-specific PCR products. This enzyme-linked oligonucleotide sorbent assay (ELOSA) relied on annealing of separate biotinylated and fluoresceinated probes to the amplified BTV nucleic acid; these complexes were captured on streptavidin-coated microtitration wells and were detected, using a horseradish peroxidase-labeled antifluorescein antibody conjugate. End-point dilution analyses of PCR products indicated that the ELOSA was more sensitive than gel electrophoretic or comparable colorimetric slot-blot hybridization techniques. The BTV PCR-ELOSA system represents a more sensitive and expeditious means of diagnosing BTV-induced viremia than does the ECE procedure currently used. The combination of ELOSA with PCR should facilitate practical application of nucleic acid technology to diagnostic veterinary medicine.

The effects of 2 drugs, xylazine and propofol, on the urethral pressure profile were compared. Seven female dogs were sedated by administration of one drug, then the other, and urethral variables were measured. In the dogs sedated with propofol, the mean +/- SD, maximal urethral closure pressure (51 +/- 7.4 cm of H2O) was significantly (P < 0.05) higher than the value when dogs were sedated with xylazine (23.3 +/- 7.6 cm of H2O). Results were compared with those obtained by various authors, in particular for nonsedated dogs. It is concluded that propofol is a good drug for investigation of the urethral pressure profile, whatever its effect on maximal urethral closure pressure.

During the spring of the first year of a vaccine study, 57 of 238 calves (24%), in which modified-live Pasteurella haemolytica vaccine (MLV) was injected twice, developed 1 or more abscesses. Abscesses were not observed after multiple visual examinations of 437 calves given killed P. haemolytica bacterin or placebo injections of similar adjuvants used in the vaccine and bacterin. Calves that developed abscesses after the second injection of MLV weighed significantly (P < 0.05) less (on the basis of body weight adjusted for weaning weight) at the second injection than did those that did not develop abscesses. Compared with calves given MLV that did not develop observable abscesses, calves developing abscesses after the second injection of MLV weighed 11.0 and 14.2 kg less, respectively, at 56 days and 112 days after injection, and they had 11.0 kg less gain at 56 days after injection. Abscess prevalence tended to be highest on certain days or at certain locations used for cattle processing, and the prevalence of abscesses increased in cattle processed later on a given day. Abscesses were not observed in 2 other groups of similarly treated calves vaccinated in the autumn or in the subsequent spring.

Eighteen female lambs with prior exposure to Haemonchus contortus infections were ovariectomized and assigned to 1 of 3 replacement regimens: 0, 25, or 250 mg of progesterone/d delivered IM. After 3 weeks of hormonal treatment, all lambs were inoculated with 100,000 infective larvae of H. contortus. After 8 weeks of hormonal treatment, a blastogenic assay was performed on blood lymphocyte populations, and the abomasum from each lamb was obtained for larval and adult worm recoveries of H. contortus. Lambs of the 25 mg of progesterone group had significantly (P < 0.05) reduced blastogenic response to concanavalin A and greater adult and larval populations, compared with controls. Lambs of the 250 mg of progesterone group had worm burdens and lymphocyte blastogenesis values intermediate between those of the other treatment groups.

A commercially available radioimmunoassay kit for measurement of human osteocalcin was validated for use in horses. For accurate measurement of equine serum osteocalcin, blood samples may be collected at a temperature between 20 and 25 C, then centrifuged within 90 minutes; serum may be stored at - 20 C in plastic tubes for up to 26 weeks. Serum may be thawed and refrozen up to 5 times without significant change in measured equine serum osteocalcin concentration. Assay sensitivity was 0.16 ng/ ml. Recovery of bovine osteocalcin standard added to equine serum was linear. Intra-assay coefficient of variation (x 100) for 2 equine serum pools was 6.9 (mean +/- SD, 13.9 +/- 1.0 ng/ml) and 7.5 (10.6 +/- 0.8 ng/ml) %. Interassay coefficient of variation for 3 equine serum pools measured in 12 assays was 12.5 (16.1 +/- 2.0 ng/ml), 12.7 (11.5 +/- 1.5 ng/ml), and 24.6 (3.0 +/- 0.7 ng/ml) %. Dilutional parallelism was documented by assaying pooled equine serum at 4 dilutions and correcting the mean result for dilution. Significant change was not observed in equine serum osteocalcin concentration for various time-of-day blood sample collections in horses housed under continuous lighting.

Ultrasonic pachymetry was used to measure central, superior peripheral, and temporal peripheral corneal thickness of 35 cats (70 eyes) with normal corneas, anterior chambers, and intraocular pressures. Mean central corneal thickness for both eyes in 3 locations for 35 cats was 578 +/- 64 micrometers. Significant differences did not exist between central and peripheral corneal thickness. Corneal thickness increased significantly (P < 0.0001) with age up to 100 months. There was no significant difference in corneal thickness with regard to sex of the cats when adjusted for age.

From 2 to 4.5 months of age, 80 crossbred gilts were reared in a conventional grower unit where they were naturally exposed to mycoplasmal and bacterial pathogens that cause pneumonia and atrophic rhinitis. At 4.5 months of age, gilts were moved to environmentally regulated rooms (4.9 X 7.3 m) and assigned at random to 1 of 2 treatment groups: low aerial concentration of ammonia (4 to 12 ppm; mean, 7 ppm) or moderate aerial concentration of ammonia (26 to 45 ppm, mean, 35 ppm). Low concentration of ammonia was obtained by flushing of manure pits weekly, whereas moderate concentration of ammonia was maintained by adding anhydrous ammonia to manure pits that were not flushed. Gilts were weighed biweekly. Mean daily gain (MDG) was less (P < 0.01) for gilts exposed to moderate concentration of ammonia than for gilts exposed to low concentration of ammonia after 2 weeks in their respective environments. By 4 and 6 weeks, however, MDG was similar between the 2 treatment groups. After 6 weeks in these environments, 20 gilts from each treatment group were slaughtered, and prevalence and severity of lung lesions and snout grades were determined. At slaughter, body weight was greater (P < 0.01) in gilts exposed to low, rather than moderate, ammonia concentration (94.5 vs 86.8 kg; SEM, 3.3 kg). Percentage of lung tissue containing lesions (18 vs 12) and snout grade (2.8 vs 3.1) were similar between gilts exposed to low or moderate concentration of ammonia. The remaining 20 gilts in each treatment group were maintained in their respective environments, exposed daily to mature boars and bred at first estrus. Age at puberty was similar between gilts exposed to low or moderate concentration of ammonia (208 vs 205 days; SEM, 1.3 days), even though weight at puberty was less (P < 0.03) for gilts exposed to low concentration of ammonia than for gilts exposed to moderate concentration of ammonia (109.7 vs 118.2 kg; SEM, 4.5 kg). At day 30 of gestation, number of live fetuses (10.6 vs 11.7), fetal length (2.53 vs 2.57 cm), and fetus-to-corpus luteum ratio (0.85 vs 0.78) were similar between gilts at low and moderate ammonia environments. These data indicate that exposure of gilts to mean aerial ammonia concentration of 35 ppm in environmentally regulated rooms depressed MDG for 2 weeks, but failed to alter onset of puberty or litter size at day 30 of gestation.

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.

Age, species, and disease state may substantially alter the disposition and clearance of pharmacologic agents. This is particularly important when drugs with low therapeutic index are used in ill neonates. Pharmacokinetic variables for phenylbutazone were determined in 24- to 32-hour-old healthy and endotoxemic calves after IV administration of a single dose (5 mg/kg of body weight, IV). Elimination halflife was 207 and 168 hours, and clearance was 0.708 and 0.828 ml/kg/h in healthy and endotoxemic calves, respectively. Intravenous infusion of endotoxin at the dose (2 micrograms/kg over 4 hours) given did not significantly alter any of the calculated pharmacokinetic variables. Serum thromboxane B2 concentration was significantly (P = 0.05) suppressed for 3 hours after phenylbutazone administration in healthy calves and for 4 hours in endotoxin-challenged calves. Daily administration of phenylbutazone (10 mg/kg loading, then 5 mg/kg for 9 days) to healthy and endotoxemic calves failed to induce any lesions consistent with nonsteroidal anti-inflammatory drug toxicosis.