Hemodynamic and analgesic effects of medetomidine (15 microgram/kg of body weight, IM) and etomidate (0.5 mg/kg, IV, loading dose; 50 micrograms/kg/min, constant infusion) were evaluated in 6 healthy adult Beagles. Instrumentation was performed during isoflurane/ oxygen-maintained anesthesia. Before initiation of the study, isoflurane was allowed to reach end-tidal concentration less than or equal to 0.5%, when baseline measurements were recorded. Medetomidine and atropine (0.044 mg/kg) were given IM after recording of baseline values. Ten minutes later, the loading dose of etomidate was given IM, and constant infusion was begun and continued for 60 minutes. Oxygen was administered via endotracheal tube throughout the study. Analgesia was evaluated by use of the standard tail clamp technique and a direct-current nerve stimulator. Sinoatrial and atrial-ventricular blocks occurred in 4 of 6 dogs within 2 minutes after administration of a medetomidine-atropine combination, but disappeared within 8 minutes. Apnea did not occur after administration of the etomidate loading dose. Analgesia was complete and consistent throughout 60 minutes of etomidate infusion. Medetomidine significantly (P < 0.05) increased systemic vascular resistance and decreased cardiac output. Etomidate infusion caused a decrease in respiratory function, but minimal changes in hemodynamic values. Time from termination of etomidate infusion to extubation, sternal recumbency, standing normally, and walking normally were 17.3 +/- 9.4, 43.8 +/- 14.2, 53.7 +/- 11.9, and 61.0 +/- 10.9 minutes, respectively. All recoveries were smooth and unremarkable. We concluded that this anesthetic drug combination, at the dosages used, is a safe technique in healthy Beagles.

A study was conducted to investigate whether aspiration of amniotic fluid is associated with a deleterious effect on absorption of colostral immunoglobulins or on blood gas and acid-base values of healthy newborn calves. Fourteen calves purchased from commercial sources were transported to a research facility immediately after birth and fed colostrum with known concentrations of immunoglobulins. Blood samples for gas analyses were collected within 5 hours of birth, 24 hours later, and prior to euthanasia. Between 3 and 5 days of age, calves were euthanatized by an overdose of barbiturates. Eleven calves had evidence of bronchoaspiration of amniotic fluid, as determined by presence of meconium, squamous epithelium, or keratin in histologic sections of fixed lung or by cytologic analysis of bronchoalveolar lavage fluid. Blood gas tensions and pH were within reference ranges in 11 of 14 calves. Aspiration of amniotic fluid could not be linked to any specific changes in blood gas tensions, acid-base status, or absorption of colostral immunoglobulins. Presence of keratin and meconium in the lungs often was accompanied by mild exudative alveolitis and focal atelectasis. It was concluded that aspiration of small amounts of amniotic fluid with or without meconium is common in calves and is not associated with hypoxemia, respiratory acidosis, or failure of passive transfer.

Six foals were deprived of colostrum for the first 36 hours after birth and, instead, received reconstituted powdered milk. Five control foals suckled their dams naturally. Blood samples were obtained from all the foals after birth and at approximately weekly intervals until at least 5.5 months of age. Sera were analyzed for hemolytic complement activity, complement component C3, and correlating IgG concentration. Hemolytic complement (P = 0.0145) and C3 (P = 0.0002) values were significantly higher in colostrum-deprived foals (CDF) than in naturally nursed foals at 2 to 5 days of age. In addition, significantly (P = 0.0149) higher IgG concentration was found in CDF than in naturally nursed foals between 3 and 5.5 months of age. It was concluded that the observed high complement activity in CDF within 2 to 5 days of age may provide an alternative in immune defense for IgG-deprived foals after failure of colostral transfer.

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.

An ELISA was developed to detect antibodies to the 41-kd flagellin (P41) of Borrelia burgdorferi in serum obtained from cattle. Absorption studies, immunoblot analysis, immunoelectron microscopy, and correlation of results of the P41-ELISA and the P39-ELISA as well as measurement of the antibody to P41 in calves challenge-exposed with Borrelia theileri were used to assess the specificity of the P41-ELISA. Antigens derived from Escherichia coli, Leptospira interrogans serovar hardjo, and B burgdorferi were used for absorption studies and immunoblot analysis. Antibodies to P41 of B burgdorferi cross-reacted with antigens of E coli, but were not cross-reactive with L hardjo. A value 3 SD higher than the mean of the negative-control population of cattle was defined as the minimum value cutoff value) for a positive result by the P41-ELISA. Use of this value for classification of test results reduced the predicted rate of false-positive results attributable to E coli cross-reactivity to 1%. Immunoblot analysis revealed that test-positive serum from cattle reacted mainly with 41-, 39-, 34-, and 31-kd proteins of B burgdorferi, as well as several smaller proteins. Immunoelectron microscopy revealed that serum from cattle that was test-positive by the P41-ELISA bound to the flagellin and outer membrane of B burgdorferi. Results of absorption studies, immunoblot analysis, and immunoelectron microscopy were correlated and indicated that serum from cattle that was test-positive by P41-ELISA had stronger reactivity to B burgdorferi antigens than to antigens of E coli or L hardjo. The concentrations of antibodies measured by P41-ELISA and P39-ELISA testing were highly correlated [R(2)=0.78]. Calves challenge-exposed with B theileri also had test-positive results by the P-41-ELISA as early as 2 weeks after exposure, but serum antibody concentrations decreased to prechallenge-exposure concentrations by 9 weeks after exposure. We concluded that the P41-ELISA was useful as a screening method to detect B burgdorferi infections in cattle.

Serum C-reactive protein (CRP) concentration was measured, using an automated immunoturbidimetric assay, in 44 clinically normal dogs and 67 dogs with band neutrophil count greater than or equal to 10(9) cells/L, and values were found to be significantly (P less than or equal to 0.05) different. Correlation of serum CRP concentration and band neutrophil count in the 67 dogs with greater than or equal to 10(9) band neutrophils/L resulted in a statistically significant P less than or equal to 0.05), but low correlation coefficient of 0.34. Serum CRP concentration and CBC values were determined for 6 clinically normal dogs undergoing anesthesia (controls) and 6 clinically normal dogs undergoing anesthesia and ovariohysterectomy. Significant alterations in CBC results and serum CRP concentration, compared with baseline values, were lacking in dogs of the control group. Serum CRP concentration was significantly (P less than or equal to 0.05) increased above baseline values in dogs undergoing surgery and was significantly (P less than or equal to 0.05) increased, compared with values in control dogs by 12 hours after surgery. In dogs undergoing surgery, serum CRP concentration was also significantly (P less than or equal to 0.05) different from values in control dogs at 28 and 36 hours, but not at the 76- and 124-hour sample collection times. Alterations in CBC values compatible with possible or convincing inflammation were detected in 83% of the dogs undergoing surgery at the 8- and 12-hour postsurgery sample collection times, 100% of dogs at 16, 22, 28, and 36 hours after surgery, 83% of dogs at 52 and 76 hours after surgery, 67% of dogs at 100 hours after surgery, and 0% of dogs at 124 hours after surgery. It was concluded that significant increases in CRP, concentration in dogs with surgical trauma were not detected earlier than CBC alterations compatible with possible or convincing inflammation.

To provide long-term gastric fistulas for collection of third-compartment gastric contents, Janeway mucosal tube gastrostomy was performed, using a gastrointestinal stapling instrument, in 6 castrated adult male llamas. Mean operative time (+/- SEM) was 65 +/- 4.16 minutes. All llamas survived the 6-week study period. Of the 6 llamas, 5 did not have signs of abdominal pain and returned to preoperative food consumption amounts within 36 hours. One llama had mild intermittent signs of abdominal pain daily for 7 days before returning to preoperative amount of food consumption. All gastrostomies leaked small amounts of gastric contents around indwelling 6- to 8-mm cannulas at the skin surface. Gastric contents did not leak when cannulas were dislodged from gastrostomy stomas. Replacement of cannulas was rapid and easy. Gravity-flow sample collection was best accomplished through 8-mm cannulas. Mean (+/- SEM) weight loss was detected in all llamas (15 +/- 3 kg) and was associated with frequent nonfeeding and stress of sample collection. Gross necropsy findings were unremarkable in 5 of 6 llamas. All mucosal tube gastrostomies were patent, and there was no evidence of peritonitis. One llama had a single fibrous adhesion connecting the operative site with the ascending colon. Histologically , small (2.5- to 15-mm diameter) partial-thickness mucosal erosions identified at the tube gastrostomy-gastric wall junctions may have been associated with indwelling gastric cannulas. The Janeway gastrostomy was generally well tolerated in the llamas and should be considered as a useful long-term fistulation technique.

Serologic testing to detect persistent IgG titer directed at Salmonella lipopolysaccharide (LPS) has proven useful in detecting Salmonella carrier cattle without clinical signs of disease and in seroepidemiologic studies. Although little cross-reactivity exists between most Salmonella serogroups, groups B (O1, 4 [5], 12) and D (O1, 9, 12) share somatic (LPS cell wall) antigens O1 and O12, which results in some cross-reactions. This may be unimportant in most instances, because group-B and group-D carriers need to be identified and culled. It may be desirable in some situations, such as when trying to control S dublin, to determine which serogroup is present in a given herd. For this reason, a procedure to produce a pure O9 group-D antigen was developed. Salmonella dublin (group D) was grown by use of standard procedures, and LPS was extracted by use of the phenol-water method. The LPS was then oxidized with sodium periodate, dialyzed, reduced with sodium borohydride, cleaved with hydrochloric acid, and again dialyzed. This procedure successfully cleaved the saccharides comprising O antigens 1 and 12, leaving a pure O9 ELISA antigen. Sera from cattle vaccinated or naturally infected with S typhimurium, S agona, and S schwarzengrund (all group B), S montevideo (group C1), and S dublin (group D) were tested by ELISA, using modified and unmodified antigens. When the ELISA antigen used was the chemically modified (pure O9) group-D antigen, elimination of cross-reactions confirmed the structural loss of cross-reacting O1 and O12 antigens.

Collagen type I was purified from equine skin and flexor tendon, and type II collagen was purified from equine articular cartilage. The proteoglycans in these tissues were extracted, using guanidine HCl; the collagens were solubilized, using pepsin digestion, then were selectively precipitated with Nacl. Gel electrophoresis indicated that the precipitates contained only type I or type II collagen. Amino acid analysis indicated that collagen constituted > 97% of the total protein in the precipitates. Hydroxylation of proline was 42.0 t 0.6% (mean SEM) in alpha 1(I) and alpha 2(I), and was 48.1 +/- 1.3% in alpha 1(II) chains. The hydroxylation of lysine was 23.2 +/- 0.7% in alpha 1(I) and 34.1 0.9% in alpha 2(I) chains from tendon, and 49.6 +/- 4.3% in alpha 1(II) chains from cartilage. The cyanogen bromide (CB)-peptide patterns of chromatographically purified equine alpha 2(I) and alpha 1(II) chains were similar to those published previously for rat, bovine, and human alpha 2 and alpha 1 chains. However, the CB-peptide pattern of the equine alpha 1(I) chain resembled the guinea pig alpha 1(I) chain, which has no methionine between CB7 and CB6. Purified equine alpha 1(I)CB7,6 contained no methionine, methionine sulfoxide, or homoserine lactone. Mass of 42.26 kd was determined by use of mass spectrometry, and N-terminal sequence analysis established that the first 12 amino acids of this CB7,6 were identical to the sequence of human alpha 1(I)CB7. Because of this species specific difference in structure of the alpha 1(I) chain, equine Cb-peptides should be used as standards in studies of variations in the proportions of type I and type II collagens in equine tissues expressing the phenotype of fibrous tissue and cartilage.

Endotoxin given in vivo has been shown to inhibit endothelial dependent relaxation, and augment adrenergic (norepinephrine) contractions in isolated palmar digital arteries of horses. A study, using tumor necrosis factor (TNF) in vitro, was performed to determine the possible cause of these vascular alterations. Palmar digital arteries were surgically removed from 6 horses under general anesthesia, cut into 4-mm vascular rings (4 segments/horse), suspended in tissue baths, and attached to force displacement transducers for measurement of vascular tension. Four in vitro treatment groups were evaluated: group 1, control; group 2, TNF (5,100 pg of TNF/ml); group 3, 10x TNF (10 times previous TNF concentration); group 4, TNF plus L-arginine (5,100 pg of TNF/ml and 10(-6) M L-arginine). The appropriate drug(s) was/were added to each tissue bath 10 minutes before dose-response tests were performed for acetylcholine, bradykinin, norepinephrine, and 5-hydroxytryptamine (serotonin). Concentrations needed to induce 50% maximal relaxation or contraction (EC50) and maximal percentage relaxation or contraction were determined. Arteries exposed to TNF (group 2) had significantly (P = 0.04) decreased maximal relaxation to acetylcholine and increased maximal contraction to norepinephrine, compared with control arteries, but values did not differ from those for arteries of groups 3 and 4. Maximal relaxation to bradykinin or contraction to serotonin were not different between treatment groups. Mean EC50 values for bradykinin, norepinephrine, and serotonin did not differ among the 4 treatment groups. Mean EC50 values for arterial segments' response to acetylcholine in group 4 were significantly (P = 0.04) increased, compared with control segments, but did not differ from those for segments of groups 2 and 3. The decreased endothelial dependent relaxation to acetylcholine and enhanced maximal contraction to norepinephrine were similar to vascular alterations caused by endotoxin, indicating that TNF may be responsible for endotoxin-induced vascular changes in vitro and in vivo in horses.