DIAGNOSIS OF URINARY TRACT OBSTRUCTION IN DOGS USING DUPLEX DOPPLER ULTRASONOGRAPHY

The ability of duplex Doppler ultrasonography to assist with the diagnosis of urinary tract obstruction was investigated in a study of 5 dogs with surgically induced, unilateral ureteral obstruction. The resistive index (RI) of obstructed kidneys was compared to that of controls and to the contralateral unobstructed kidneys. The RI was also evaluated following relief of obstruction. On the basis of an RI measurement ≥0.70 indicating obstruction, a sensitivity of 73% and a specificity of 77% was determined for the diagnosis of obstruction with Doppler ultrasonography. Although mean RI was elevated in obstructed kidneys compared to controls, it was concluded that a high false-negative rate (27%) limits the clinical usefulness of Doppler ultrasonography for the detection of urinary obstruction in dogs. The RI difference between obstructed and nonobstructed kidneys was also evaluated within individual animals, but the magnitude of difference between kidneys did not significantly improve the detection rate for obstruction.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.     

Protein, energy and dry matter consumption by racing standardbreds: A field survey

A field survey involving 112 Standardbred race horses in 14 stables at a Detroit racetrack was conducted to determine feeding practices of the Standardbred trainers, to estimate crude protein (CP), digestible energy (DE), and dry matter (DM) consumption by racing Standardbreds, and to compare those intakes with 1989 recommendations of the National Research Council (NRC), “Nutrient Requirements of Horses.” Trainers were interviewed regarding: 1) the age and sex of the horses; 2) their feeding practices, and 3) the horse's training and racing schedule. Only adult horses which were actively racing and continuously stabled at the track were included.

Body weights (BW) estimated using a chest girth measurement resulted in an overall mean BW of 449 kg. Body condition scores were established for each horse with an overall mean score of 5.7 which indicated average body condition for a racing Standardbred at this track. Typical rations from each stable were weighed, and feed samples of hays and concentrates were analyzed at a commercial laboratory to determine CP, DM, acid detergent fiber (ADF), and estimated energy density. A computer program calculated CP, DE, and DM values for each horse's ration based on amounts fed. The software program included with the 1989 NRC publication was used to compare estimated nutrient intakes with current NRC recommendations for a horse of a given BW.

All trainers fed a variety of hays and commercial grain mixes, and five trainers fed oats separately. The mean total intake of feed for all horses on an “as fed” basis was 16.1 kg. The estimated mean DM intake for all horses was 14.4 kg vs. NRC recommended 10.6 kg. The mean percentage of rough-age in the ration for all stables was 64% vs. a NRC recommendation of 35%. The mean CP% on a DM basis for all stables' rations was 14.5% vs. the NRC recommendation of 11.4%. The mean daily CP and estimated DE intakes for all horses were 2113 g and 37.6 Meal, respectively, in contrast to current NRC recommendations of 1189 g CP and 29.7 Meal DE. These data indicate that estimated CP, DE, and DM consumption are above the recommendations of NRC in 1989.     

Minimal Anesthetic Concentration and Cardiopulmonary Dose Response of Isoflurane in Ducks

The minimal anesthetic concentration (MAC) for isoflurane was determined during spontaneous ventilation in nine male Peking ducks (7 to 12 weeks of age; 3.0 +/- 0.4 kg). While each bird was awake, arterial blood was collected for analysis of pH, PaCO2, and PaO2. After anesthesia was induced with isoflurane in oxygen, MAC was determined for isoflurane in each bird during spontaneous ventilation in a manner similar to MAC determinations in mammals. Pulmonary dose-response data were collected at 1 MAC and 1.5 MAC. Anesthetic index (Al; an index of anesthetic-induced apnea) was calculated from ducks that became apneic. The MAC for isoflurane was 1.30 +/- 0.23% (mean +/- SD). There was a dose-dependent decrease in ventilation as evidenced by a statistically significant increase in PaCO2. Apnea or unacceptable hypercarbia (PaCO2 greater than 110 mm Hg), or both, were common occurrences at end-tidal isoflurane concentrations greater than 1.5 MAC. Anesthetic index calculated from four ducks was 1.65 +/- 0.13 (mean +/- SEM). There was no significant difference between the means of either heart rate or mean arterial blood pressure in birds at 1.0 and 1.5 MAC.     

Pathologic changes of experimental simian varicella (Delta herpesvirus) infection in African green monkeys (Cercopithecus aethiops)

Gross and microscopic lesions of experimental simian varicella (Delta herpesvirus) infection in African green monkeys (Cercopithecus aethiops) are described. In stratified squamous epithelium, such as the epidermis, tongue, and esophagus, focal areas of epidermal hyperplasia, ballooning degeneration, and blood-filled vesicle formation with ulceration were apparent. Most visceral organs were involved, and the changes included necrosis, hemorrhage, and characteristic intranuclear eosinophilic inclusions in a variety of cells. A generalized vascular involvement was present with intranuclear inclusions in the endothelial and smooth muscle cells in various organs. The nervous system was normal on gross and microscopic examination. Virus titer and serum transferase values were correlated with the clinical signs of infection.     

硒与家禽产品的保健作用

家禽产品质量的改善不仅在于其滋味、质地和色泽的改善。利用鸡体贮存重要养分的能力，也许能使禽肉和禽蛋增强其对消费健康的有利作用从而为人类健康作出新的贡献。     

Renal Clearance, Urinary Excretion of Endogenous Substances, and Urinary Diagnostic Indices in Healthy Neonatal Foals

Urine (U) and serum (S) were obtained every 2 hours during a 12- or 24-hour period from eight healthy 96-hour-old pony or horse foals. Dams' milk samples were obtained concurrently. Urine volume was measured during this 12- or 24-hour period. The mean amount of urine produced was 148 +/- 20 ml/kg/day. Baseline urinalyses were evaluated on all foals at two days of age, before any manipulation. Urine generally was dilute (less than 1.008) but the specific gravity was as high as 1.027 in one normal foal. Continuous (12 or 24 hour) urinary catheterization resulted in bacteriuria but not white blood cells in the urine. Prolonged catheterization did not cause foals to become febrile or exhibit clinical signs of cystitis or other illness. Urinary electrolyte excretion, urinary electrolyte clearances, and fractional electrolyte excretions (FE) were measured. When compared with normal values reported in adult horses, excretion, clearance, and FE were similar for sodium (Na) but higher for potassium (K), phosphorus (P), and calcium (Ca). There were no significant differences between data collected during different time periods, and it was concluded that the use of single sample urine/serum estimates of fractional excretion in the neonatal foal was an appropriate indicator of the renal handling of electrolytes, and when viewed in conjunction with urinalysis and other serum parameters, a valuable aid to evaluating renal function.     

Macrolide-lincosamide resistance determinants in streptococcal species isolated from the bovine mammary gland

Seventy one streptococci isolated from dairy cows with clinical mastitis were tested for erythromycin and lincomycin susceptibility. Ten isolates (7.1%) were resistant to erythromycin and/or lincomycin and seven were constitutive and three were inducibly resistant. Nine of the isolates hybridized with one or more of the Erm probes tested and eight isolates gave PCR products with rRNA methylase primers. The Erm determinants were transferable at frequency of 10⁻⁵ to 10⁻⁶ per recipient.     

Measurement of vertical forces and temporal components of the strides of horses using instrumented shoes

Instrumented shoes were used to measure the vertical forces exerted by horses moving at a variety of gaits. Two types of shoes were used; one contained a single transducer positioned over the center of the frog and the second contained transducers located at the toe and both sides of the heel. Horses were shod with these instrumented shoes and walked and trotted over a force plate. Forces were simultaneously recorded from the transducers in the shoes and from the force plate. Comparisons were made between the amount and duration of the forces exerted on the transducers and the vertical and horizontal forces recorded from the force plate. Forces recorded from the single transducer shoes showed strong correlations with the forces recorded from the force plate for horses moving at the walk; however, at the trot only moderate correlations occurred between these forces. At both the walk and trot, forces recorded from each side of the heel and the total forces occurring on all three transducers from the front hooves of horses shod with three transducer shoes showed strong correlations to the vertical forces recorded from the force plate.Vertical forces were also recorded from the instrumented shoes as horses walked, trotted and galloped on a track straightaway. Forces recorded from normal horses shod with single transducer shoes on all four feet were greater on the forelimbs than the rear limbs at the walk and trot. At the gallop, forces were highest on the lead front followed by the nonlead front, lead rear and nonlead rearlimb, respectively. Forces recorded from a three transducer shoe on the right front hoof of a horse walking, trotting and galloping in a right lead were highest on the medial side of the heel and occurred during the middle of the support period. Peak forces on the toe occurred at or near the time of heel lift.The results of these studies indicate that these instrumented shoes have advantages over the methods previously used to measure locomotor forces. These instrumented shoes can be used to simultaneously record the temporal components and the amount and distribution of vertical forces exerted during consecutive strides of horses moving at a variety of gaits.