bluuebunny/crossref_metadata_2025 huggingface dataset:
Glucose intolerance in cats given short-term therapies of prednisolone and megestrol acetate
Authors: Middleton Deborah J. , Watson A. D. J.
Published: February 2025

Six cats were each given prednisolone (2 mg/kg of body weight/day) and megestrol acetate (5 mg/cat/day) on separate occasions for 8 days. The drugs induced similar increases in fasting blood glucose concentrations and decreases in glucose excretion rates in the cats. Usually, each cat developed reduced tolerance of an iv glucose load; concomitant fasting hyperglycemia occurred in 3 cats after prednisolone therapy, and in 1 of these 3 cats after megestrol acetate.
Identification of feline monocytes and neutrophils as effector cells in antibody-dependent cellular cytotoxicity: Sequential analysis, using light microscopy, histochemistry, and scanning electron microscopy
Authors: Kooistra L. , Splitter G. A. , Albrecht R. M.
Published: February 2025

Feline monocytes and neutrophils functioned as effector cells in antibody-dependent cellular cytotoxicity (adcc) against antibody-coated chicken erythrocytes. Using light microscopy, effector cell populations were identified in effector-target cell interactions, with further characterization of these identical individual effector cells by histochemical evaluations and scanning electron microscopy. Monocytes and neutrophils, but not lymphocytes, were observed attacking target cells. Carbonyl iron depletion of monocytes and neutrophils from peripheral blood leukocytes caused a marked reduction from a mean of 62% to 3.6% lysis in adcc as measured by a 4-hour 51Cr release assay. Effector cells functioning in the adcc reaction were visualized, using sequential analysis and light microscopy, histochemistry, and scanning electron microscopy.
Pasteurella haemolytica leukotoxin: Comparison of 51chromium-release, trypan blue dye exclusion, and luminol-dependent chemiluminescence-inhibition assays for sensitivity in detecting leukotoxin activity
Authors: Chang Yung-Fu , Renshaw Harland W.
Published: February 2025

Dilutions of concentrated, dialyzed Pasteurella haemolytica culture supernatant were caused to react with bovine neutrophil (pmn) suspensions, and then the trypan blue dye exclusion (tbde), 51chromium (51Cr)-release, and luminol-dependent chemiluminescence-inhibition (ldcll) assays were done to compare their relative sensitivities in detecting biological activity of Ρ haemolytica leukotoxin (cytotoxin). The culture supernatant was concentrated approximately 200:1, and when caused to react as an undiluted preparation with bovine pmn, it was cytotoxic for 38.6% and 80.4% of pmn as determined by tbde and 51Cr-release assays, respectively. This undiluted leukotoxin preparation caused 100% inhibition of the luminol-dependent chemiluminescence responses of bovine pmn. The LDCLl assay was the most sensitive of the 3 in vitro assays for Ρ haemolytica leukotoxin activity—being approximately 17 times and 2,480 times more sensitive than the 51Cr-release and tbde assays, respectively.

The relative advantages and disadvantages of the 3 assays as in vitro systems for detecting and titrating leukotoxin activity and investigating the role of leukotoxin in disease pathogenesis and immunity are discussed. Because of its sensitivity, specificity, economy, technical ease, and potential for adaptation to automation, the LDCLl assay would seem to be the in vitro assay of choice for quantitating Ρ haemolytica leukotoxin activity. To aid standardization of studies of leukotoxin between different laboratories, it is suggested that Ρ haemolytica leukotoxin activity be quantitated and expressed as chemiluminescence inhibitory units. It is proposed that 1 chemiluminescence inhibitory unit be defined as that amount of Ρ haemolytica leukotoxin activity capable of totally abrogating, in a 20-minute incubation period, the luminol-dependent chemiluminescence response of 1 × 106 bovine pmn incubated with heat-killed Ρ haemolytica in the presence of heat-inactivated bovine fetal serum saturated with luminol. The methods for conducting the LDCLl assay are described.
Effects of thyrotropin-releasing hormone on serum concentrations of thyroxine and triiodothyronine in healthy, thyroidectomized, thyroxine-treated, and propylthiouracil-treated dogs
Authors: Li W. I. , Chen C. L. , Tiller A. A. , Kunkle G. A.
Published: February 2025

Effects of thyrotropin-releasing hormone (trh) on serum concentrations of thyroid hormones were studied in 36 mixed-bred dogs. Dogs were randomly assigned to 7 groups. Significant increases (P < 0.05) of serum thyroxine (T4) values occurred as early as 2 hours and reached a peak at 6 to 8 hours after iv injection of 300 to 1,100 μg of trh. Thyroxine concentrations in response to a trh dose > 500 μg were similar to those observed with the 300-μg dose. Transient coughing, vomiting, salivation, and defecation after large doses (900 and 1,100 μg) were observed.

Mean serum T4 concentration decreased from 2.1 μg/dl to 0.9 μg/dl within 1 day of thyroidectomy. Clinical signs of hypothyroidism, including lethargy, dry coats, and diffuse alopecia, were present in 2 dogs at a month after surgical operation. Thyroxine concentrations were detectable for > 2 months. Injection (iv) of 700 μg of trh 6 weeks after surgical operation had no effect on serum concentration of T4 in thyroidectomized dogs.

In 5 T4-treated dogs, trh (700 μg, iv) significantly increased the serum T4 value, indicating that pituitary thyrotropes were responsive to trh, in spite of daily medication of 0.8 mg of T4.

Four dogs were treated orally with 200 mg of propylthiouracil/day for 5 weeks. Intravenous injection of 700 μg of trh in propylthiouracil-treated dogs had no effect on the serum T4 concentration, indicating that trh had no effect on serum T4 values in these dogs during the experimental period.

These results indicate that trh can replace bovine thyrotropin for the canine thyroid function test. The recommended dosage is 300 to 500 μg. The best time to obtain blood samples is 6 to 8 hours after iv injection. Thyroxine should be used as the indicator of thyroid function, since there is lack of adequate release of triiodothyronine in response to the recommended trh dosage used.
Evaluation of the myoelectrical activity of the equine ileum infected with Strongylus vulgaris larvae
Authors: Berry C. R. , Merritt A. M. , Burrows Colin F. , Campbell Martha , Drudge J. H.
Published: February 2025

Five weanling ponies were subjected to an intensive 6-Week deworming program after which 4 Ag-AgCl bipolar electrodes were implanted surgically on the distal ileum. For 3 hours each day for 5 consecutive days, ileal myoelectrical activity was recorded from fed ponies under 3 sequential conditions: preinoculation, after oral administration of 1,000 killed Strongylus vulgaris infective larvae (3 ponies), and after oral administration of 1,000 live S vulgaris infective larvae. Recordings were analyzed for slow wave frequency, percentage duration of phases I, II, and III of the migrating myoelectrical complex (mmc), and the frequency of distinct, rapidly migrating action-potential complexes within phase 2 of the mmc.

After administration of live and killed infected 3rd-stage larvae, there was a marked increase in the number of disrupted phase ΙΠ complexes, and a significant (P < 0.001) increase in the number of migrating action-potential complexes. In addition, after inoculation of live 3rd-stage larvae, there was a significant increase (P < 0.001) in the percentage of time that the mmc was occupied by prolonged periods devoid of spike activity (phase I).

The results indicate that S vulgaris larval mucosal penetration and submucosal migration can cause changes in ileal myoelectrical activity that could cause colic, and that larval antigen alone within the lumen may disrupt ileal motility.
Fimbriae and enterotoxins associated with Escherichia coli serogroups isolated from pigs with colibacillosis
Authors: Wilson R. A. , Francis D. H.
Published: February 2025

A comprehensive study of 223 Escherichia coli isolates from pigs with colibacillosis included determination of O serogroups, detection of heat-labile enterotoxin, heat-stable enterotoxin (STa and STb), and identification of K88, K99, 987-P, F-41, and type 1 fimbriae.

The incidence of the various E coli types among isolates of pigs of different ages was also determined. Escherichia coli bearing K88 fimbriae accounted for 48% of all isolates studied, were most often of serogroup 0157, 0149, or 08, and usually produced labile toxin alone or in combination with STa or STb. These E coli were commonly isolated from pigs in each age group studied (0 to 5 days, 6 to 10 days, 11 to 24 days, and > 24 days). Escherichia coli bearing 987-P accounted for 30% of the isolates, were most often of serogroup 0141 or 020, and usually produced STa. Escherichia coli bearing K99 accounted for 13% of the isolates, usually were of serogroup 0101 or 08, and almost always produced STa. Escherichia coli bearing 987-P or K99 were most often isolated from pigs < 6 days of age. Fimbriae F-41, when identified, were usually on E coli of serotype 0101:K99. Although infrequently found, type 1 fimbriae were on E coli of most of the serogroups identified in this study.
Experimentally induced infectious bovine rhinotracheitis virus infection during early pregnancy: Effect on the bovine corpus luteum and conceptus
Authors: Miller J. M. , Van Der Maaten M. J.
Published: February 2025

Pairs of heifers were inoculated iv with infectious bovine rhinotracheitis virus on postbreeding days (pbd) 7, 14, 21, or 28, and were euthanatized 13 to 15 days after inoculation. Reproductive tracts were examined for cytopathologic changes (light microscopy), virus (cell culture), and viral antigen (immunohistochemical evaluation).

Heifers inoculated on pbd 7 or 14 had mild oophoritis characterized by foci of necrosis and mononuclear cell accumulations in the corpus luteum. Most of these heifers also had a few necrotic follicles in at least one ovary. Heifers inoculated on pbd 21 or 28 did not have corpus luteum lesions, but necrotic follicles were numerous in both ovaries. Viral antigen was observed in all ovarian lesions, and infectious virus was isolated from a few of the affected tissues.

The uteri of all heifers inoculated on pbd 21 or 28 and 1 heifer inoculated on pbd 7 contained normal-appearing concepti. The uterus of the other pbd 7 heifer contained a degenerating conceptus that was infected with infectious bovine rhinotracheitis virus, as determined by viral isolation, immunohistochemical evaluation, and electron microscopy. Heifers inoculated on pbd 14 were not pregnant at necropsy, but histologic evidence was found that the postbreeding estrous cycle had been longer than normal, indicating that early embryonic death had occurred.
Campylobacter-like organisms isolated from gastric mucosa of ferrets
Authors: Fox J. G. , Edrise B. M. , Cabot E. B. , Beaucage C. , Murphy J. C. , Prostak K. S.
Published: February 2025

Campylobacter-like organisms (clo) were isolated from gastric lesions in 1 ferret and gastric mucosa of 2 healthy ferrets. The organism was not isolated from biopsies of gastric mucosa of 14 other healthy ferrets, 1 of which had small gastric lesions located at the pylorus. Lesions from which clo were isolated were located in the antrum of 1 ferret and were classified as inflammation with repair. Affected gastric tissue was highly vascularized with fibrous connective tissue surrounding irregularly shaped glands. Necrosis and ulceration of adjacent mucosa also were observed. Using Warthin-Starry stain, Campylobacter-like organisms were seen on and in the glandular epithelium of the ferret with gastric lesions from which clo were isolated.
Canine atrioventricular node: Scanning electron microscopy and enzyme histochemistry
Authors: Sandusky George E. , White Sandy L. , Wightman Karen A.
Published: February 2025

Morphologic features of the canine atrioventricular (av) node were evaluated, using histochemical cholinesterase reactions and scanning electron microscopy. Three distinct regions of the av node were observed: the transitional zone, superficial av node, and deep av node. The transitional zone lacked distinct cellular arrangement, and the cells were large and round with extensive branching on the ends. Superficial av nodal cells were elongated, tightly packed, and smaller than were transitional cells. The superficial av node was the densest zone of the av node. Cell-to-cell contact was end-to-end. Deep av nodal cells were long, formed laminated fascicles, were larger than the superficial av nodal cells, and were continuous with the av bundle.
Cross-sectional area of the aditus laryngis and rima glottidis before and after transection of the left recurrent laryngeal nerve in the horse
Authors: Martin G. S. , Beadle R. E. , Haynes P. F. , Watters J. W.
Published: February 2025

The ventral-to-dorsal height of the rima glottidis was measured from lateral pharyngeal radiographs after correction for magnification. The rima glottidis height was used to enlarge accurately endoscopic photographs of 5 horses taken before and after transection of the left recurrent laryngeal nerve. Areas of the rima glottidis and aditus laryngis were measured, using a computerized digitizer. Mean area of the aditus laryngis was 1,908 mm2 before neurectomy and 1,346 mm2 after neurectomy (P = 0.025). Mean area of the rima glottidis was 1,198 mm2 before neurectomy and 805 mm2 after neurectomy (P = 0.025). Mean width of the rima glottidis was 31 mm before neurectomy and 20 mm after neurectomy (P = 0.001). Significant differences were not found between the pre- and postneurectomy heights of the rima glottidis.
Pulmonary function in dogs after intercostal thoracotomy: Comparison of morphine, oxymorphone, and selective intercostal nerve block
Authors: Berg R. John , Orton E. Christopher
Published: February 2025

A thoracotomy was performed at the left 5th intercostal space in 24 dogs. Dogs were assigned to 4 groups of 6 dogs each. Postoperative analgesia was administered as follows: group 1—control, no analgesia; group II—morphine (0.5 mg/kg of body weight); group III—oxymorphone (0.1 mg/kg); group IV—selective intercostal nerve block with bupivacaine HCl. Respiratory rate, minute volume (VE), and arterial blood gases were measured during the recovery period. Ventilation-perfusion mismatch was estimated by calculation of the alveolar-arterial oxygen tension difference.

Arterial carbon dioxide tension (Paco2) in the control and selective intercostal nerve block groups remained within the normal range and did not differ significantly (P < 0.05) between groups. During the first 60 to 90 minutes after surgery, Paco2 tension was increased significantly (P < 0.05) in the groups given morphine and oxymorphone. Hypoventilation in the groups given narcotics resulted from significant reductions (P < 0.05) in the respiratory rate and VE and produced significant (P < 0.05) respiratory acidosis and hypoxemia. Three dogs in the groups given narcotics had a panting response that resulted in increased respiratory rates and VE. This response did not improve alveolar ventilation in these dogs, which was evidenced by increased Paco2 values. Hypoventilation, respiratory acidosis, and hypoxemia in the groups given narcotics improved significantly with time, presumably because of drug clearance. Values for alveolar-arterial oxygen tension difference indicated moderate ventilation-perfusion mismatch secondary to anesthesia in all groups; however, significant differences (P < 0.05) between the groups were not observed.
Anatomie distribution of encysted cyathostome larvae in the horse
Authors: Reinemeyer Craig R. , Herd R. P.
Published: February 2025

The large intestines of 6 horses were divided by length into 12 segments, and each segment was washed and weighed. At least 5% by weight of each segment was examined by mural transillumination, and encysted cyathostome larvae were counted. Total numbers of larvae in each segment were calculated. Encysted larvae (98%) were present in the proximal 7 segments of the large intestine (cecum and proximal 75% of the ventral colon), and 2% were present in the distal 25% of the ventral colon and entire dorsal colon. Encysted larvae (6%) were located in the dorsal colon of 1 heavily infected horse. Larval density was greatest in the cecum, which harbored 57% of encysted worms yet contributed only 27% to the total weight of the large intestine.

Larvae dissected from tissue cysts consisted of species that were highly prevalent as adult worms. However, there were few Cylicostephanus longibursatus, probably because of the small size and fragility of its 4th-stage larvae.
Pathologie findings in the oviducts of mares
Authors: Saltiel Alberto , Páramo Rosa , Murcia Clara , Tolosa Jorge
Published: February 2025

Oviducts from 325 mares were evaluated macroscopically, and oviducts from 124 mares were evaluated microscopically. Two hundred and eighty-five (87.69%) of the mares had at least 1 macroscopic lesion and 116 (93.54%) had at least 1 microscopic lesion. The most frequently seen macroscopic lesions were adhesions, paraovarian cysts, and thick fibrous bands. Microscopically, intraepithelial cysts, slight, focal lymphocytic infiltration in the infundibular-ampullary region, and proteinoid material in the oviductal lumen were the most common findings. In general, the proximal segments of the oviduct were more affected than were the distal segments. Forty-nine (90.74%) of the 54 pairs of oviducts collected from pregnant mares had at least 1 macroscopic or microscopic lesion.
Infectious bovine keratoconjunctivitis: Contact transmission
Authors: Kopecky Kenneth E. , Pugh George W. , McDonald Timothy J.
Published: February 2025

The transmission of Moraxella bovis was studied in calves in the absence of the face fly (Musca autumnalis) or environmental conditions that might insult the eye. Thirty calves were placed in 10 groups of 1 experimentally infected calf and 2 contact calves each. Over 40 days, only 1 eye in 1 contact calf developed clinical infectious bovine keratoconjunctivitis. The organism was recovered in only 8 of 20 contact calves, whereas infection and disease occurred in all experimentally infected calves. Transmission of M bovis occurring in the absence of some other intervening factor was probably of minimal importance. Seemingly, herd preventive treatment would be most effective when flies and environmental factors are at a minimum.
Bovine peritoneum: Fibrinolytic activity and adhesion formation
Authors: Trent A. M. , Bailey J. V.
Published: February 2025

The fibrinolytic activity of peritoneum was evaluated in 4-month-old calves before and after peritoneal trauma. In each calf, a peritoneal resection, abrasion, sutured incision, and nonsutured incision were performed. These 4 trauma sites were evaluated for fibrinolytic activity and adhesion formation at 1 of 6 posttrauma intervals (1, 2, 3, 5, 8, or 14 days). Peritoneal plasminogen activator and fibrinolytic inhibitor activities from pre- and posttrauma samples were evaluated, using a fibrin-slide incubation technique. Calf peritoneal specimens consistently had fibrinolytic inhibitor activity, but did not have plasminogen activator activity. Significant differences were not found between fibrinolytic activity before or after trauma and a significant correlation was not found between fibrinolytic activity and the presence of or severity of adhesions.
A newly designed tensiometer
Authors: Lee Alice H. , Swaim Steven F. , Pedersoli John M. , McGuire John A.
Published: February 2025

A newly designed tensiometer is described in detail. The tensiometer was used to test the tensile strengths of skin wounds on the trunks of 12 female laboratory Beagles at 5, 9, and 14 days after operation. The tensile strengths increased significantly from day 5 to day 14. The newly designed tensiometer could be used to obtain accurate in vivo measurements of the tensile strengths of skin wounds.
Preferential grazing by cattle on glyphosate-treated fescue pastures
Authors: Kisseberth William C. , Buck William B. , Mansfield Manford E. , Manuel Richard K.
Published: February 2025

Cattle grazing preferences on fescue pastures treated with the herbicide glyphosate at a rate of 2.52 kg/ha by surface application were determined, and the time course of the effect was characterized. An initial grazing preference for treated pasture was observed for the first 5 to 7 days. Over the next 15 days, this preference was lost because of decreasing amounts of herbicide on the herbage and/or desiccation of the herbage.
Experimentally induced rabies in four cats inoculated with a rabies virus isolated from a bat
Authors: Trimarchi Charles V. , Rudd Robert J. , Abelseth Melvin K.
Published: February 2025

Four cats were inoculated im with rabies virus isolated from the salivary gland of a naturally infected big brown bat (Eptesicus fuscus). The 4 cats developed clinical signs of rabies after a median incubation period of 42 days. The median duration of clinical illness was 5 days. Results of fluorescent antibody evaluation, mouse inoculation, and tissue culture isolation indicated large differences in virus concentrations in various areas of the cns of individual cats. These differences also were observed between cats. Rabies virus was isolated from the salivary glands and saliva of 2 cats; urinary bladder was the only other nonneural tissue found infected. Our observations indicated that cat rabies can be caused by bat rabies virus; that cats thus infected have infectious saliva during aggressive behavior and can therefore transmit the disease; and that adequate specimens of hippocampus, cerebellum, and brain stem are essential for reliable determination of rabies infection. The findings support recommendations for regular rabies vaccination of cats, even in areas of rabies-free terrestrial mammals.
Effects of estradiol on hematopoietic and marrow adherent cells of dogs
Authors: Gaunt Stephen D. , Pierce K. R.
Published: February 2025

Hematopoietic and marrow adherent cells were examined in 5 ovariohysterectomized dogs treated once with 1.5 mg of 17β-estradiol cyclopentylpropionate/kg of body weight. All dogs initially developed thrombocytopenia and neutrophilic leukocytosis, with megakaryocytopenia and an increased myeloid/erythroid ratio of the marrow. Later, 2 dogs became thrombocytopenic and neutropenic, with megakaryocytopenia, decreased myeloid/erythroid ratio, and increased concentration of plasma cells and mast cells in the marrow. The concentration of marrow granulocytemacrophage colony-forming units (cfu-gm) was decreased at 2 and 3 weeks in all dogs after estradiol treatment. The concentration of marrow fibroblast cfu-f was decreased in all estradiol-treated dogs at 1 and 2 weeks. The ability of marrow adherent cells to support cfu-gm colony formation was unchanged in estradiol-treated dogs. Estradiol sulfate at final concentrations of 10−8 to 10−4M did not affect the in vitro growth of cfu-gm and cfu-f, or the hematopoietic ability of marrow adherent cells from nontreated dogs.
Uric acid and phosphorus excretion in dogs with lymphosarcoma
Authors: Page Rodney L. , Leifer Connie E. , Matus Robert E.
Published: February 2025

Serum uric acid and phosphorus concentrations were determined for 27 dogs with multicentric lymphosarcoma before and after chemotherapy. Mean serum uric acid values in dogs before treatment were significantly higher (P < 0.05) than those of a control group of healthy dogs. Serum uric acid values did not change after treatment. Of the 27 dogs, 13 had 24-hour urine collections to determine endogenous creatinine clearance and quantitation of uric acid and phosphorus excretion before and after treatment for lymphosarcoma. Mean values for 24-hour creatinine clearance before and after treatment were statistically similar in dogs with lymphosarcoma, although the values were lower than those in a normal range. Total urinary phosphorus excretions were increased significantly (P < 0.01) after treatment without change in fractional excretion. Chemotherapeutic agents used accounted for the significant (P < 0.05) increase in urine volume after treatment and may have affected the excretion of uric acid and phosphorus.

Seemingly, dogs with uncomplicated lymphosarcoma rarely have renal dysfunction or clinically important alterations in uric acid or phosphorus excretion secondary to rapid tumor lysis. However, preexisting renal disease or systemic complications, such as hypercalcemia, may be associated with increased risk of further renal impairment during treatment.
Equine thyroid function assessment with the thyrotropin-releasing hormone response test
Authors: Lothrop Clinton D. , Nolan H. Lynn
Published: February 2025

The effect of thyrotropin-releasing hormone (trh) on equine thyroid function was determined by quantifying serum thyroxine (T4) and 3,5,3′-triiodothyronine (T3) before and after trh administration. Thyrotropin-releasing hormone was administered iv to adult horses (n = 5) and ponies (n = 6) at a dose of 1 mg or 0.5 mg, respectively. Serum T4 and T3 concentrations were determined before and 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 24 hours after trh administration. Serum T4 increased from a basal concentration of 24.4 ± 8.7 ng/ml (mean ± sd) to a maximum value of 48.2 ± 10.2 by 4 hours after trh administration. Serum T3 increased from a basal concentration of 0.44 ± 0.18 ng/ml to a maximum value of 1.31 ± 0.37 ng/ml by 2 hours after trh administration. Seemingly, trh increases serum concentrations of T4 and T3 and may be useful as a test of equine hypophysis-thyroid function.
Effects of prednisolone on glucose tolerance and insulin secretion in the dog
Authors: Wolfsheimer K. J. , Flory W. , Williams M. D.
Published: February 2025

Effects of prednisolone on glucose tolerance and insulin secretion were evaluated in healthy dogs. Dogs were given 1 mg of prednisolone/kg of body weight/day (n = 5) or 2 mg of prednisolone/kg/day (n = 6) orally for 3 weeks. Intravenous glucose tolerance tests (600 mg/kg) were administered before and after treatment to evaluate plasma glucose in fasting dogs, glucose fractional clearance rate, serum insulin in fasting dogs, insulin peak response, total insulin secretion, and insulinogenic index.

A significant difference (P < 0.05) in plasma glucose in fasting dogs was observed for the 2 mg/kg dose, although values were still within the reference range. There was no significant effect on glucose fractional clearance rate (glucose tolerance) or insulin secretion. Seemingly, peripheral insulin resistance resulting in hyperinsulinemia or decreased glucose tolerance could not be identified in association with 1 or 2 mg of prednisolone/kg/day for 3 weeks in healthy dogs.
Effects of tenotomy of the tensor tympani muscle on the acoustic reflex in dogs
Authors: Sims Michael H. , Weigel Joseph P. , Moore Robert E.
Published: February 2025

The acoustic reflex (ar) was recorded from 12 healthy mixed-breed dogs. Latency and amplitude were measured from ipsilateral and contralateral ar at stimulus frequencies of 1 and 2 kHz and intensities of 70 to 110 dB sound pressure level for ipsilateral ar and 70 to 120 dB hearing level for contralateral ar. Mean latencies for ipsilateral and contralateral ar were between 33.46 and 206.10 ms and between 45.26 and 180.89 ms, respectively, and amplitudes were between 0.14 and 1.79 cm3 and between 0.31 and 1.86 cm3 of air, respectively. Stimulus frequencies and intensities had significant effects (P < 0.05) on ipsilateral and contralateral ar latencies and amplitudes. Ipsilateral and contralateral ar decays were determined by measuring compliance change during a 10-s pure-tone stimulation at frequencies of 1 and 2 kHz at an intensity of 10 dB above ar threshold. Reflex decays for 1 kHz and 2 kHz frequencies averaged 5.74% and 9.71%, respectively, for ipsilateral ar and 5.08% and 5.40%, respectively, for contralateral ar. Bilateral tympanograms and brain stem auditory-evoked responses were performed on each dog. Mean normal static compliance of the middle ear, as determined by typanometry, was 0.15 cm3.

Unilateral tenotomy of the tensor tympani muscle was done on 6 of the 12 dogs, and each of the preceeding procedures were repeated within 1 week after surgical operation. Transection of the tensor tympani tendon did not alter (P > 0.05) the latencies or amplitudes of 1 kHz- or 2 kHz-evoked contralateral ar, the latency or amplitude of 1 kHz-evoked ipsilateral ar, or the amplitude of 2 kHz-evoked ipsilateral ar. However, the latency of 2 kHz-evoked ipsilateral ar was significantly (P < 0.05) increased. Reflex decay increased significantly (P ≤ 0.001) for the contralateral reflex elicited by the 2 kHz stimulus. Neither compliance of the middle ear system nor amplitude and latency of the brain stem auditory-evoked response were affected (P > 0.05) by tenotomy. Since tenotomy eliminates participation of the tensor tympani in the ar, these data indicate that contraction of this muscle is not primarily responsible for the compliance changes recorded during an acoustic reflex in dogs.
Gentamicin tissue concentrations in equine small intestine and large colon
Authors: Snyder Jack R. , Pascoe John R. , Hietala Sharon K. , Holland Melissa , Baggot Desmond J.
Published: February 2025

Gentamicin sulfate (2.2 mg/kg of body weight, iv) was given to anesthetized horses. Jejunal and large colon tissue samples (1 g), serum, and urine were collected over a 4-hour period. Maximum gentamicin concentrations in serum (10.06 ± 2.85 μg/ml) occurred at 0.25 hours after injection. Maximum gentamicin concentrations in the large colon (4.13 ± 1.80 μg/ml) and jejunum (2.26 ± 1.35 μg/ml) occurred in horses at 0.5 and 0.33 hours, respectively. Tissue concentrations decreased in parallel with serum concentrations and were still detectable at the end of the 4-hour period.

During the time that samples were collected, the total amount of gentamicin excreted in the urine ranged from 7.21 ± 3.11 mg to 11.91 ± 7.12 mg, with a mean urinary concentration of 57.01 ± 5.37 μg/ml. Over the 4-hour collection period, the fraction of dose that was excreted unchanged in the urine was 4.8 ± 1.9%.

Pharmacokinetic analyses of the serum concentration-time data gave a serum half-life of 2.52 ± 1.29 hours, volume of distribution of 227 ± 83 ml/kg, and body clearance of 1.12 ± 0.26 ml/min/kg. The half-lives of the antibiotic in the jejunum and large colon were 1.32 and 1.83 hours, respectively.
Comparison of antipseudomonad activity of chlorine dioxide/chlorous acid-containing gel with commercially available antiseptics
Authors: Kenyan Alan J. , Hamilton Susan G. , Douglas Diane M.
Published: February 2025

A chlorine dioxide-containing gel was compared with 3 commercially available antimicrobials and 1 antibiotic intended for topical use. This gel was tested at 0.5 × and 4 × and was found to be more effective as a 4 × gel in treating Pseudomonas aeruginosa-infected excised wounds on mice. To further compare this gel with other antiseptics, a murine bioassay was developed. This wound model consisted of an excised cutaneous wound on the dorsum of mice which were irradiated (800 rad) and inoculated with Ρ aeruginosa at 10-fold dilutions, from 10−2 to 10−10. The wounds were observed for latency of infection or mice survival time as a function of concentration of viable organisms remaining after treatment. The advantage of this model was demonstrated where a standard curve based on latency did not consume as many test subjects and yet provided an estimate of viable organisms in each wound. In this model, the chlorine dioxide-containing gel was more active than were preparations of providone-iodine, chlorhexidene, or silver sulfadiazine and was similar to polymyxin-bacitracin-neomycin ointment as a topical antiseptic. The effectiveness of the tested gel was reduced if delays in treatment were longer than 1 hour.
Congenital cardiac defects in calves
Authors: Gopal T. , Leipold H. W. , Dennis S. M.
Published: February 2025

In a 14-year study of calves with cardiac defects, 36 had 78 congenital cardiac defects: ectopia cordia cervicalis (n = 10 defects), common aortic trunk (n = 3 defects), dextraposed aorta (n = 8 defects), duplicated major trunks (n = 1 defect), hypoplastic aorta (n = 2 defects), interventricular septal defect (n = 11), interatrial septal defect (n = 2), left ventricular hypoplasia (n = 10), patent ductus arteriosus (n = 5), patent foramen ovale (n = 5), right ventricular hypoplasia (n = 10), cor triloculare biatriatum (n = 1), endocardial fibroelastosis with calcification (n = 3), and valvular hematomas (n = 7). All septal defects were high in location and ranged from 5 to 35 mm in diameter. One calf with a septal defect also had bilateral microphthalmia.
In vitro and in vivo association of African swine fever virus with swine erythrocytes
Authors: Quintero Julio C. , Wesley Ronald D. , Whyard Terry C. , Gregg Douglas , Mebus Charles A.
Published: February 2025

The association of African swine fever virus (asfv) with swine erythrocytes in vivo, in high titers, was verified by inoculating 30 pigs with 17 asfv isolates and assaying their plasma and washed erythrocyte fractions for residual virus. Viral antigens were specifically localized on the surface of in vitro and in vivo swine erythrocytes, using the fluorescent antibody technique and 3 monoclonal antibodies specific for asfv. The same monoclonal antibodies immunoprecipitated virus-specific polypeptides of molecular weights 13 kd and 73 kd from asfv-infected Vero cells. Erythrocytes from viremic swine infected with Lisbon-60, Dominican Republic, Badajoz-M98, or Cameroon isolates of asfv were studied by transmission electron microscopy. Virus was found in membrane depressions at the surface of erythrocytes. These surface depressions resembled stages of smooth surfaced pits. Erythrocytes from viremic pigs were fragile osmotically.
Plasmid profile analysis of bovine isolates of Pasteurella haemolytica
Authors: Boyce John R. , Morter Raymond L.
Published: February 2025

Pasteurella haemolytica isolates, obtained from cattle with respiratory tract disease, were characterized as to serotype, antimicrobial susceptibility, and plasmid content. Strains isolated from 2 groups of cattle were compared. Remarkable similarity was seen in the plasmid profiles of isolates of the same serotype. In contrast, isolates of 2 different serotypes had totally different plasmid profiles.
Antibacterial activity of dilute povidone-iodine solutions used for ocular surface disinfection in dogs
Authors: Roberts Steven M. , Severin Glenn A. , Lavach J. D.
Published: February 2025

Bacterial cultures of specimens from healthy canine eyelids and ocular surfaces were found to demonstrate bacterial growth in 69.7% (53/76) of the eyes sampled. Organisms most commonly isolated included: Staphylococcus aureus, α-hemolytic Streptococcus sp, S epidermidis, and Escherichia coli. Evaluation of dilute povidone-iodine solutions for effectiveness as ocular surface disinfectants was conducted. Bacterial growth initially detected in 32 of 46 eyes was not detected after disinfection with a 2-minute scrub and 2-minute soaking procedure, using 1:2, 1:10, or 1:50 dilutions of a povidone-iodine solution that contained 1% available iodine. The eyelid and ocular surfaces of 16 eyes were disinfected with 1:100 povidone-iodine solution. Bacterial growth initially present in 10 of 16 eyes was present in 1 eye after disinfection and consisted of a single colony of Ε coli. After eyes were disinfected with 1:10, 1:50, or 1:100 povidone-iodine solutions, there was no evidence of corneal epithelial edema or sloughing. In 15 eyes subjected to disinfection with the 1:2 dilution, one instance of epithelial corneal edema was noticed. A 1:50 dilution of povidone-iodine is recommended as an ocular surface disinfectant for use in presurgical situations.
Thiacetarsamide in dogs with Dirofilaria immitis: Influence of decreased liver function on drug efficacy
Authors: Holmes Robert A. , McCall John W. , Prasse Keith W.
Published: February 2025

The influence that decreased functional hepatic mass had on blood arsenic concentrations in dogs after they were treated with thiacetarsamide, on the clearance of indocyanine green (icg), on arsenic concentrations in the heartworm (Dirofilaria immitis), and on drug efficacy was studied. Dogs which were partially hepatectomized and treated with thiacetarsamide (1.76 mg/kg, 2 times a day for 2 days) had a significantly (P < 0.001) reduced icg clearance, significantly (P < 0.01) higher arsenic levels in heartworms, and a significantly (P < 0.01) higher proportion of heartworms killed than did dogs that were sham operated and treated with thiacetarsamide or sham operated and untreated. There were no significant differences in blood arsenic (thiacetarsamide) concentrations 2 minutes after injection between hepatectomized and non-hepatectomized groups. More male heartworms were killed than were female worms in the thiacetarsamide-treated groups.

Indocyanine green half-life was longer (12.43 minutes) in the hepatectomized group than it was in the nonhepatectomized sham-operated groups (5.09 and 4.94 minutes). Indocyanine green clearance rate was lower in the hepatectomized group (0.54 ml/min/kg) than that in the nonhepatectomized groups (1.36 and 1.56 ml/min/kg).

A parallel seemed to exist between icg and thiacetarsamide removal from the blood by the liver. This parallel also was suggested in the higher worm arsenic (thiacetarsamide) concentrations for the hepatectomized group vs that for nonhepatectomized groups. Apparently, the slower the removal of thiacetarsamide from the blood by the liver, the higher the worm arsenic level and, consequently, the higher the worm kill.
Drug residues in milk after intrauterine injection of oxytetracycline, lincomycin-spectinomycin, and povidone-iodine in cows with metritis
Authors: Kaneene John B. , Coe Paul H. , Smith James H. , Rapnicki Paul , Smith Cynthia L. , Gerloff Brian , Morrow David A.
Published: February 2025

A study was conducted to document the maximum retention times of antimicrobial residues in milk after their use in intrauterine treatment of metritis in lactating cows and to evaluate several risk factors hypothesized to influence the retention time of these drugs.

Oxytetracycline (3 g), lincomycin-spectinomycin (2 g of one-third lincomycin and two-thirds spectinomycin), or povidone-iodine (6 g) were given to cows with metritis by intrauterine route. The Bacillus stearothermophilus var calidolactis disk assay was performed on each milk sample. Of the 61 cows treated with oxytetracycline, 30 had residues in their postinjection milk for variable periods (range, 12.5 to 44.0 hours; mean, 26.6 ± 10.3). Of the 47 cows treated with lincomycin-spectinomycin, 17 had residues in their postinjection milk for various periods (range, 14.5 to 24 hours; mean, 19.5 ± 8.9). Povidone-iodine was not detected in milk. Because a high number of cows (n = 61) were treated with oxytetracycline, only data from these cows were used in testing the influence of 3 factors (severity of metritis, time after parturition when cows with metritis were treated, and parity) on maximum retention of the drug in milk. Severity of metritis did not have a significant influence (P ≥ 0.1) on the maximum retention time of the drug. The retention time decreased linearly with the increase of time after parturition when the cow with metritis was treated. First lactation cows had a significantly (P ≤ 0.01) shorter retention time than did older cows.
Effect of prostaglandin E2 on rib fracture healing in Beagles: Histomorphometric study on periosteum adjacent to the fracture site
Authors: Shih Mei-Shu , Norrdin Robert W.
Published: February 2025

A histomorphometric study was done on healing defects in the ribs of Beagles. A transverse fracture was made in the left 9th and 10th ribs. Beagles were given either ethanol vehicle (n = 6) or prostaglandin (pg) E2 orally (n = 5) for the 30-day period after surgical manipulation to time of necropsy. Double fluorescent labels to measure bone matrix mineralization were given with each of 2 fluorochrome markers-calcein before dogs were surgically manipulated and oxytetracycline hydrochloride before they were euthanatized.

The objectives were to determine the effects of fracture on regional remodeling in the periosteum, the effects of pge2 on the regional remodeling changes in the periosteum induced by the fracture, and the systemic effect of pge2 on remodeling changes of the contralateral matching sites.

The fracture in the nontreated dogs (ethanol only) stim-ulated remodeling activity in the periosteum with in-creased resorption (P < 0.01). However, after surgical manipulation (necropsy) was done, the extent of miner-alization on the bone surface was decreased and was de-creased more on the nonfractured ribs (right side) than on the fractured (healing) ribs (left side) (P < 0.05). In the treated dogs, the administration of pge2 increased the extent of mineralization on the bone surface on the healing ribs. However, as in the nontreated dogs, the administration of pge2 did not alter the decreasing pattern of mineralization when comparing the bone surfaces at necropsy with the bone surfaces before surgical manipulation was done. The extents and thicknesses of the osteoid on the 2 sides (right and left) were greater in the treated dogs than in the nontreated dogs (P < 0.01). We conclude that the regional acceleration phenomenon occurs in the periosteum of the ribs adjacent to a fracture and that the administration of pge2 alters the phase of the remodeling cycle, but has little effect on mineralization.
Hypertension in bulls and steers anesthetized with guaifenesin-thiobarbiturate-halothane combination
Authors: Semrad S. D. , Trim C. M. , Hardee G. E.
Published: February 2025

Eight bulls and steers (research animals) and 18 bulls (surgical patients) were anesthetized with guaifenesin and thiopental or thiamylal and for 90 minutes with halothane. Arterial blood pressure and heart rate were recorded in all animals. Cardiac output, plasma glucose and lactate concentrations, pcv, plasma proteins and plasma thromboxane B2 values were determined before (control) and every 15 minutes during anesthesia in the research animals. Plasma catecholamine concentrations were measured in 3 of the research animals and 3 of the surgical patients. Arterial pressure, heart rate, and plasma thromboxane B2 and catecholamine concentrations were also measured immediately after the trachea was intubated.

All animals, except one, were hypertensive during anesthesia. Heart rate during anesthesia was significantly increased, compared with control measurements, and cardiac output was decreased. Plasma glucose and lactate values significantly increased when the animals were restrained on their sides. Plasma glucose concentrations remained increased during anesthesia, but lactate decreased. Packed cell volume and plasma proteins were unchanged by the induction of anesthesia. Plasma norepinephrine concentration was unchanged during anesthesia, and epinephrine concentration was decreased. Endotracheal intubation caused a transient significant increase in arterial pressure, heart rate, and thromboxane B2 and a nonsignificant increase in norepinephrine.
Efficacy of repeated doses of levamisole, morantel, fenbendazole, and ivermectin against gastrointestinal nematodes in ewes
Authors: Hembry F. G. , Miller J. E. , Sims D. , Rodriguez S. , Stagg L. C.
Published: February 2025

Levamisole, morantel, fenbendazole, or ivermectin was administered at 2-week intervals from May 1 through Sept 14, 1985, to breeding ewes (20 ewes/drug) infected with various gastrointestinal nematodes. All ewes had fewer gastrointestinal nematode eggs per gram of feces (epg) after 2 treatments, compared with pretreatment epg counts. Ewes administered ivermectin continued to have a low mean epg (0 to 3) throughout the study. The mean epg counts of ewes treated with levamisole increased from 3 to 483 during the study. This increase was similar to that of ewes treated with morantel (7 to 485 epg). The mean epg count of fenbendazole-treated ewes increased from 4 to 192 during the study. By the end of the study, the mean epg counts when expressed as a percentage of the pretreatment epg counts were 4% (ivermectin), 249% (fenbendazole), 627% (levamisole), and 630% (morantel). With the exception of the ivermectin-treated ewes, the epg count increased almost linearly in the ewes after the 2nd anthelmintic treatment. These data indicate that the gastrointestinal nematodes (including Haemonchus contortus) may have developed more resistance to levamisole and morantel than to fenbendazole. On the basis of the epg counts, resistance to ivermectin did not develop during the 4.5-month treatment period. The percentage of ewes shedding eggs after 2, 4, and 6 anthelmintic treatments was lowest for ewes treated with ivermectin (20%) and was similar (40%) for ewes treated with 1 of the other 3 anthelmintics. At the conclusion of the study, most of the ewes (90%) were shedding at least a small number of eggs, regardless of the anthelmintic treatment. Using the epg count as the evaluation criterion, ivermectin was more effective against gastrointestinal nematodes in ewes than was levamisole, fenbendazole, or morantel.
Efficacy of an orally administered modified-live porcine origin rotavirus vaccine against postweaning diarrhea in pigs
Authors: Hoblet K. H. , Saif L. J. , Kohler E. M. , Theil K. W. , Bech-Nielsen S. , Stitzlein G. A.
Published: February 2025

A commercially available, porcine-origin rotavirus vaccine was evaluated for efficacy against postweaning diarrhea due to rotavirus infection in pigs. Weight gains were compared at 5 intervals after weaning. Visual scoring was used to evaluate fecal consistency. Rectal swab specimens were cultured for hemolytic E coli and evaluated for rotaviral antigen by use of enzyme-linked immunosorbent assay. Milk from dams and sera from pigs and dams were evaluated for rotavirus-neutralizing antibodies by use of a plaque-reduction test. Significant differences between vaccinates and controls were not found in the determinants evaluated. Selected rotavirus-positive fecal and rectal swab specimens were examined for double-stranded (ds) RNA by use of direct electropherotyping, and the results were compared with the dsRNA pattern of rotavirus propagated from the vaccine. Only electropherotypes typical of field strain virus were found in the fecal and rectal swab specimens evaluated. Sera from guinea pigs and from a gnotobiotic pig immunized against the field strain rotavirus neutralized Ohio State University strain rotavirus (homologous to the vaccine rotavirus strain), but did not neutralize the Gottfried strain of rotavirus. This indicated that, although the dsRNA electropherotypes of the field and vaccine strains of the virus were different, the serotypes were similar, if not identical.
Treatment of canine idiopathic seborrhea with isotretinoin
Authors: Fadok Valerie A.
Published: February 2025

The efficacy and safety of isotretinoin in the treatment of idiopathic seborrhea in dogs were examined. Isotretinoin was judged effective in only 1 of 8 dogs. Side effects included mild comjunctivitis, transient erythematous rash, and increased serum cholesterol and triglyceride concentrations.