Cutaneous pythiosis in the horse.

Pythiosis of horses in an invasive, ulcerative, proliferative, pyogranulomatous disease of the skin and subcutis caused by Pythium insidiosum, a fungus-like oomycete in the order Peronosporales of the kingdom Protista. Pythiosis is a form of "phycomycosis," which is a complex of pyogranulomatous diseases that also includes conidiobolomysosis, basidiobolobysosis, and disorders caused by members of the order Mucorales.

Fistulous withers in horses: 24 cases (1984-1990).

Between Jan 1, 1984 and Aug 1, 1990, 27 horses were admitted to the veterinary medical center for evaluation of fistulous withers. Nine (37.5%) of 24 horses tested for antibody to Brucella abortus were seropositive. Horses that tested seropositive were significantly (P = 0.046) more likely to have been pastured with cattle that were seropositive for B abortus, and were significantly (P = 0.010) more likely to have had radiographic evidence of vertebral osteomyelitis than were horses that tested seronegative. Five horses that were seropositive for B abortus were administered strain 19 brucella vaccine sc (n = 1) or iv (n = 4). The horse treated by sc injection of vaccine improved during hospitalization, but was lost to follow-up evaluation. Three (75%) of 4 horses treated by iv injection died, but 1 horse recovered within 4 weeks of treatment.

Ultrasonographic imaging of a keratoma in a horse.

Ultrasonography was used to confirm the tentative diagnosis of keratoma in a horse admitted for chronic progressive lameness. A definitive diagnosis of keratoma traditionally has been diagnosed by history, clinical findings, and radiographic evaluation. Confirmation of the keratoma by use of ultrasonography facilitated the formulation of a treatment plan that resolved the condition.

Eosinophilic gastroenteritis with encapsulated nematodes in a horse.

A 3-year-old Quarter Horse gelding admitted for evaluation of weight loss, signs of depression, and dermatitis of the coronary bands was found to have eosinophilic gastroenteritis. Intralesional nematodes identified as Strongylus edentatus were seen in multiple microscopic sections of the small colon, suggesting a parasitic cause of the disease.

Milk production of quarter horse mares during 150 days of lactation.

Milk production was measured in fourteen Quarter Horse mares at seven stages of a 150-d lactation period. Mares were divided into two groups of seven and fed diets containing either soybean meal or soybean meal and urea as nitrogen supplements. Rations were isocaloric, contained approximately 12.5% crude protein and were fortified with vitamins and minerals. Daily milk yield was estimated by the weigh-suckle-weigh method and milk composition was determined from samples taken by hand milking. Average daily milk yield ranged from 11.8 kg in early lactation to 9.8 kg in late lactation. Differences (P less than .01) in milk yield due to number of previous lactations were observed. Also, diet influenced (P less than .01) milk yield, with mares fed soybean meal producing an average of 1.2 kg more milk/d than mares fed urea as part of the N supplement. Further, stage (day) of lactation influenced (P less than .01) daily milk yield. The largest mean daily milk yield was measured at approximately 30 d postpartum, but the predicted lactation curve was linear (P less than .05) over the range of observations in this study. Average percentages of total solids, protein and fat over the 150-d lactation were 10.5, 2.1, and 1.3, respectively. All components decreased significantly with advancing lactation. There was a trend toward a positive association between milk yield and solids content of the milk, but it was not significant. Milk yield was not significantly related to fat content of the milk. However, milk yield and protein content were correlated (r = .23; p less than .05). As expected, solids content of the milk was positively associated with percentages of protein (r = .59; P less than .01) and fat (r = .44; P less than .01). Relationships among milk components were similar after adjustment for days in milk. However, yield of milk and composition were unassociated (P less than .05) when days in milk were held constant.

Surgical correction of deviated nasal septum and premaxilla in a colt.

A 6-month-old Appaloosa colt had a deviation of the premaxilla and nasal septum as well as a dorsal hump of the nasal bone and maxillomandibular malocclusion. Two surgical procedures were performed 12 weeks apart to correct these anomalies. An intraoral approach and autogenous rib graft were used to correct the malocclusion and deviation of the premaxilla. Osteotomy of the nasal bone and removal of the nasal septum were performed to help correct the deviation and to facilitate free air passage through the nares.

Amphotericin B for the treatment of localized subcutaneous phycomycosis in the horse.

Amphotericin B was used systemically or locally, or both, in the treatment of localized subcutaneous phycomycosis in horses. In 8 of 10 cases, the results were satisfactory. Intravenous treatment was well tolerated at an average starting daily dosage of 0.38 mg/kg, increasing up to as high as 1.47 mg/kg. It was concluded that the ideal treatment regimen would include early surgical removal of the lesion followed by daily intravenous and topical administration of amphotericin B, with periodic extirpation of small necrotic tracts as necessary.

Influence of induced hypermagnesemia and hypocalcemia on neuromuscular blocking property of oxytetracycline in the horse.

The neurally evoked contractile response of the upper lip muscles of horses anesthetized with halothane was used to evaluate the neuromuscular blocking property of oxytetracycline which was administered intravenously at total dose rate of 21 to 28 mg/kg. This dose rate did not alter the contractile response which had a mean control value (and standard error; SE) of 1.76 plus or minus 0.22 kg. Arterial blood pressure was not affected by these dose rates. Neuromuscular blocking effect of the antibiotic occurred when it was administered during partial neuromuscular blockade which had been induced by infusion of magnesium sulfate (0.12 or 0.16 g/kg). Moderate hypocalcemia induced by infusion of sodium oxalate did not enhance the neuromuscular blocking property of this antibiotic. Since the dose rates of the oxytetracycline preparation used had a small effect on calcium concentration of equine serum (smaller than 0.3 mg/dl), calcium binding does not seem to play a major role in the neuromuscular blocking effect of this antibiotic. It was concluded that the weak neuromuscular blocking effect of oxytetracycline is not a significant etiologic factor in the acute type of adverse reaction to this antibiotic that is occasionally encountered in horses.