Dynamics of plasma ferulenol concentration and its effect on the vitamin K-dependent coagulation factors, prothrombin time (PT), and activated partial thromboplastin time (APTT) were determined in 4 sheep intoxicated individually with 600 g of powdered Ferula communis variety brevifolia (FCb) given in 8 doses at intervals of 6 hours. Ferulenol was detected in the plasma of all sheep at initial blood sample collection, 6 hours after the first dose of approximately 75 g of FCb was placed in the rumen. The last observed peak of approximately 20 microgram/ml was detected at about 12 hours after the last of 8 doses, and the mean concentration then decreased to < 1 microgram/ml during the next 70 hours. Maximal concentration of ferulenol and time for plasma clearance varied with individual sheep. The PT increased steadily to a maximum of 6 times normal about 70 hours after the last peak plasma ferulenol concentration and about 80 hours after FCb administration was stopped. The PT then retumed to almost normal (ratio of 1.12) from the maximum (ratio of 6.12) within approximately 5 days. The APTT results gnerally paralleled the PT results, but the change was not as marked. Maximal PT and APTT ratios were animal-dependent and not always related to plasma ferulenol concentration. The activity of all the vitamin K-dependent coagulation factors was depressed, but the variations were unique to each factor. Factor V, a vitamin K-independent coagulation factor actually had a brief period of increased plasma activity. We concluded that the effects on PT, APTT, and vitarnin K-dependent coagulation factors induced in sheep intoxicated with FCb were consistent with the coumarinic structure of ferulenol, the intoxicating compound in FCb, which seems to have a short-term anticoagulation effect.

A crude, whole-body extract of female or male heartworms was injected IV into 28 dogs with and 22 dogs without heartworm (HW) infection. The female HW extract caused shock in 22 of 24 dogs with and 12 of 20 dogs without HW infection. The male HW extract induced shock in 4 of 4 dogs with and 1 of 2 dogs without HW infection. Prevalence of shock caused by female HW extract was significantly (P < 0.05) higher in dogs with than without HW infection; shock developed 5 to 30 minutes after HW injection. These signs were observed: marked decrease in blood pressure; collapse (initial collapse); paleness of mucous membranes; weak heart sounds; dyspnea; skin coldness; intestinal hyperperistalsis, and defecation; increases in RBC count, serum total protein concentration, serum osmolality, serum Na and blood glucose concentrations; and decreases in neutrophil, eosinophil, and platelet counts. Alanine transaminase, alkaline phosphatase, and lactate dehydrogenase activities increased substantially from the time of initial collapse to 24 hours after HW injection. Of 39 dogs with shock, 29 recovered from initial collapse, but 5 of the 29 subsequently collapsed again (secondary collapse), with bloody diarrhea followed by death. Of these 39 dogs, 6 died during initial collapse without bloody diarrhea, and 4 were euthanatized during initial collapse. It was confirmed that HW extract had, in fact, induced shock. These clinical, hematologic, and biochemical findings were fundamentally similar to those associated with shock resulting from administration of drugs, such as diethylcarbamazine and milbemycin D, in microfilaremic dogs with HW infection.

Bronchoalveolar lavage (BAL) was performed on 16 horses to determine whether it caused local or diffuse inflammation in the lungs. In 7 horses, BAL was performed in both lungs twice, 48 hours apart. Although total cell counts of the BAL samples did not change significantly, there were increased numbers and percentage of neutrophils in the second lavage fluid samples. In 5 horses, BAL was performed in 1 lung and repeated 48 hours later in the same lung and in the corresponding airway in the contralateral lung. The absolute cell count and percentage of neutrophils were significantly (P = < 0.05) increased in the second sample from the lung that was lavaged twice. In 4 horses, BAL was performed in 1 lung and 48 hours later, repeated in an adjacent airway to the first BAL site, and in the corresponding airway in the contralateral lung. Significant differences were not detected in the total or differential cell counts of the BAL fluid recovered at any time, except for an increase in neutrophil percentage in the second sample in the contralateral lung. The increased neutrophil percentage values were within the range of normal for healthy horses. Results of the study suggested that, in horses, BAL induces a localized pulmonary neutrophil influx that persists at least 48 hours and is characterized by a relative and absolute increase in the number of neutrophils in the lavage fluids.

Influence of age, breed, and stage of pregnancy on hepatic ultrasonographic findings of cows was determined. In addition, the relation between body weight, height at the withers, milk production, and the measurements determined via ultrasonography was investigated. The liver of 186 cows was examined ultrasonographically. The cows comprised Swiss Braunvieh, Simmental, and Holstein breeds, and age ranged from 2.5 to 11.5 years. The ultrasonographic findings of the liver, gallbladder, caudal vena cava, and portal vein were described, and the position, size, thickness, and distal angle of the liver were determined. In addition, the position and diameter of the caudal vena cava and portal vein were determined. There was no significant difference between any of the variables determined and breed or age. Therefore, measurements for the 3 breeds and for the various ages were summarized into 1 group. There were significant correlations between body weight, milk production, and size and thickness of the liver. In 3 pregnant cows, the liver was examined ultrasonographically 8 times during the course of pregnancy. Positive correlation was detected between stage of pregnancy and diameter of the caudal vena cava. There was a negative correlation between stage of pregnancy and diameter of the portal vein. In 23 cows, the ultrasonographically determined measurements of the liver were compared with those determined at slaughter. Weight of the liver correlated well to thickness of the liver determined via ultrasonography.

A total of 21 calves were inoculated IV with 1 of the following isolates of bovine viral diarrhea virus (BVDV); CD87 (n = 10), NY-1 (n = 3), NADL (n = 5), or were sham-inoculated with virus-free medium (n = 3). Subsequent to inoculation, platelet counts were monitored to detect differences between noncytopathic (CD87, NY-1) and cytopathic (NADL) isolates in their ability to induce thrombocytopenia. Platelet count decrease throughout infection was statistically analyzed by comparing the slope of the line drawn from the count on the day of infection to the lowest count achieved by that calf. Significant difference was observed in the CD87-inoculated calves and in the NY-1-inoculated calves, compared with those of the same control group. Significant difference was not observed in the slope of platelet count decrease between the cytopathic NADL-infected calves and control-group calves. The data indicate that noncytopathic BVDV isolates may more easily induce thrombocytopenia than do cytopathic isolates in immune-naive, immunocompetent calves; acute infection with 1 cytopathic BVDV isolate (NADL) did not induce thrombocytopenia. In addition, although each calf seroconverted, virus was rarely isolated from mononuclear cells obtained from calves with cytopathic infections. At some point after infection, virus was always isolated from each of the calves undergoing noncytopathic infections, and occasionally, transient association of noncytopathic BVDV antigen with platelets was observed during these infections.

Plasma concentration of penicillin G was evaluated in beef steers after administration of either a combination of benzathine penicillin G and procaine penicillin G in a 1:1 mixture at a dosage of 9,000 U/ kg of body weight, IM (n = 5), 24,000 U/kg, IM (n = 5), or 8,800 U/kg, SC (n = 5), or benzathine penicillin G alone at a dosage of 12,000 U/kg, IM (n = 7). Plasma concentration of penicillin G was measured by use of a high-performance liquid chromatography assay that had a limit of determination of 0.005 micrograms/ml. At a dosage for this combination of 9,000 U/kg IM, and 8,800 U/kg, SC, which are approved label recommendations in Canada, and the United States, respectively, mean (+/- SEM) peak plasma concentration was 0.58 (+/- 0.15) and 0.44 (+/- 0.02) micrograms/ml, respectively. Although plasma penicillin concentration was quantifiable for 7 days in the steers that received 9,000 U/kg, IM, and for 4 days in the steers that received 8,800 U/kg, SC, the concentration was < 0.1 micrograms/ml in both groups after the first 12 hours. After administration of the combination at dosage of 24,000 U/kg, IM, there was an initial peak plasma concentration at approximately 2 hours; thereafter, plasma concentration decreased slowly, with half-life of 58 hours. Although plasma penicillin G concentration was quantifiable for 12 days at this dosage, concentration was < 0.1 micrograms/ml after the first 48 hours. After the initial 48 hours, plasma concentration of penicillin was of similar magnitude and decreased at similar rate for the combination at dosage of 24,000 U/ kg and for 12,000 U/kg of benzathine penicillin G alone. Most of the plasma penicillin G concentration in the first 24 hours after administration of a 1:1 combination of benzathine penicillin G and procaine penicillin G is attributable to absorption of procaine penicillin G. After the first 48 hours, most of the plasma drug concentration appeared to be produced by absorption of penicillin G from benzathine penicillin G. Absorption of benzathine penicillin G produces quantifiable plasma penicillin G concentrations for several days, but they are below the level of susceptibility for most bacteria.

Doxorubicin was encapsulated in canine erythrocytes, treated with 0.32% glutaraldehyde, and administered at a dosage equivalent to 30 mg of free doxorubicin/m(2) of body surface area to dogs with diagnosis of lymphosarcoma. Compared with administration of free doxorubicin, this method of drug delivery substantially reduced peak plasma concentration and prolonged higher plasma concentration of doxorubicin. As such, this method was comparable to continuous IV infusion. Previous studies have indicated this method's potential for reduction in toxic side effects, particularly cardiotoxicosis, while allowing higher total doses of doxorubicin to be administered. In this study, doxorubicin encapsulated in glutaraldehyde-treated erythrocytes induced a triphasic exponential decay of doxorubicin from plasma, the highest relative contribution to the total area of the curve being the terminal phase. The treatment was effective in inducing complete and partial remissions of lymphosarcoma, with minimal acute toxicosis and no evidence of cardiotoxicosis. However, substantial, unanticipated, chronic, nonregenerative myelosuppression developed, and was most strikingly expressed as profound thrombocytopenia. Efforts to ameliorate or circumvent this toxic effect will be required prior to further consideration of this doxorubicin delivery system for treatment of systemic neoplasia.

To determine whether body direction in a trailer affects the degree to which a horse is excited (and presumably stressed) during transport, heart rates were measured in 8 Thoroughbred geldings transported over a 32-km route of county roads while tethered facing forward or backward in a 4-horse stock trailer. Heart rates also were measured on the horses while they were tethered facing forward or backward in the same trailer while it was parked. Heart rates decreased during the first 10 minutes for both groups, and remained stable after the first 15 minutes. Heart rates were not significantly different between horses facing forward or backward during transport or while parked. Heart rates were significantly (P < 0.05) higher for horses during transport, compared with those of horses in a parked trailer whether facing forward or backward.

The nucleotide sequence of a chromosomally encoded antigen-expressing gene of Borrelia coriaceae was determined and used as a target for the polymerase chain reaction (PCR). Two primer sets were designed specifying the amplification of 269- and 701-bp DNA fragments. Primer set I, producing the short amplicon, was tenfold more sensitive than primer set II. As little as 10 fg of purified B coriaceae DNA could consistently be detected. The PCR assays, containing controlled numbers of whole spirochetes, allowed detectable amplification of 2 to 10 organisms. An internal, nonradioactively labeled gene-specific probe verified specificity of the PCR amplicons. Neither primer set cross-reacted with other related spirochetes. This PCR assay was adapted and found suitable for identification of B. coriaceae in biological samples, such as blood and thymus. Evidence for presence of B. coriaceae in biological samples was not found in tissue samples obtained from experimentally infected cows and their fetuses. These data failed to establish a definite association between B. coriaceae and epizootic bovine abortion.

During growth, central venous, right ventricular, pulmonary arterial, Pulmonary capillary wedge, and systemic arterial pressures, heart rate, and cardiac Output were repeatedly measured in 41 Friesian calves, considered as having conventional muscular conformation, and in 19 Belgian White and Blue double-muscled calves. A total of 123 and 70 recordings were collected in conventional and double-muscled calves, respectively. These circulatory indices were calculated: stroke volume, cardiac and stroke indices, pulmonary and systemic pulse pressures, pulmonary and systemic vascular resistance indices, and right and left ventricular work indices. Results indicated that systemic arterial and pulse pressures, as well as cardiac output, stroke volume, cardiac and stroke indices, and right and left ventricular work indices were significantly (P less than or equal to 0.05 to 0.001) lower but, in contrast, pulmonary and systemic vascular resistance indices were significantly (P less than or equal to 0.001) higher in double-muscled than in conventional calves. Right-sided vascular pressures and heart rate were similar in the 2 groups. These results indicated that global cardiac performance may be considerably poorer in double-muscled calves. Diminished cardiac performance of double-muscled calves appears to be related neither to relative bradycardia nor to reduced ventricular preload. The potential role of increased ventricular afterload or of reduced myocardial contractility in double-muscled cattle should be determined by direct measurements.