Effects of milbemycin oxime on adult hookworms in dogs with naturally acquired infections

Previous work indicated that adult Ancylostoma caninum can be removed from experimentally infected dogs, using a formulation of milbemycin oxime at dosage of 0.5 mg/kg of body weight. To determine the efficacy of this treatment in dogs naturally infected with adult hookworms, 24 mixed-breed dogs with patent hookworm infections were purchased from an out-of-state vendor, and 6 male and 6 female dogs were assigned to either a control group or a group that would be treated. Dogs were treated 10 days after their arrival and were euthanatized 1 week after treatment. Beginning 3 days before treatment, fecal samples were collected daily from all dogs, and the number of Ancylostoma eggs per gram of dry weight of feces was determined from each sample. By 1 week after treatment, the mean number of eggs being passed by the treated dogs had dropped from 12,700 to 10 eggs/g of dried feces; there was no apparent change in fecal egg counts for dogs of the control group. At necropsy, the mean number of adult A caninum in dogs of the treated and control groups was 1.3 and 56, respectively; in these naturally infected dogs, efficacy of treatment was calculated to be 97.8%. The mean number of adult Trichuris vulpis recovered in dogs of the control and treated groups at necropsy was 24 and 0, respectively, which yielded treatment efficacy of 100%. Although Uncinaria stenocephala and Toxocara canis appeared also to be removed by use of this dosage, too few dogs were in the study to calculate meaningful efficacies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pathological and virological studies of experimental parvoviral enteritis in calves

Calves held in isolation showed a progressive decline in maternally derived antibody titres to bovine parvovirus but low concentrations of inhibitors resistant to heat and kaolin treatment persisted as the animals matured. These inhibitors had both haemagglutination inhibition and plaque neutralising activity and were considered to be of non-specific origin. Following oral challenge with bovine parvovirus, calves developed mild to moderate diarrhoea, with lymphopenia and viraemia. Sequential virological and immunofluorescent studies showed that the virus initially infected tonsils and intestinal tract, subsequently spreading to systemic lymphoid tissues. Histological and scanning electron microscopic examinations revealed moderate small intestinal villus atrophy and fusion due to crypt damage, together with lymphoid necrosis predominantly associated with the intestinal tract and thymus. Although the disease was not very severe, this may have been because the low parasite burden in the animals reduced mitotic activity in susceptible tissues.     

Effect of Feeding Frequency and Romet-Medicated Feed on Survival, Antibody Response, and Weight Gain of Fingerling Channel Catfish Ictalurus punctatus after Natural Exposure to Edwardsiella ictaluri

Abstract The efficacy of restrictive feeding regimes and Romet®-medicated feed (formulated at 40.5-mg Romet-30 premix/kg feed) fed at 2.0% body weight was evaluated under field trial conditions for the treatment of naturally induced Edwardsiella ictaluri infections in fingerling channel catfish. After detection of an Edwardsiella ictaluri epizootic, fish were fed medicated and non-medicated feed every day, every other day and every third day for the duration of the experiment. In addition, experimental treatments also included fish that were completely withheld from feed and those provided Romet-medicated feed for five consecutive days followed by non-medicated feed fed daily. Feeding frequency and diet significantly affected survival and weight gain. Survival was greatest among fish that were completely withheld from feed or that were fed medicated feed every other or every third day. The use of non-medicated feed every other or every third day was equally as effective for reducing Edwardsiella ictaluri associated mortalities as feeding Romet-medicated feed on a daily basis. Feeding fish Romet-medicated feed for five consecutive days was not an effective treatment. Agglutinating antibody titers against Edwardsiella ictaluri were significantly lower in all groups of fish fed Romet-medicated feed for the duration of the experiment. These data indicate that feeding frequency is a primary factor affecting the severity of Edwardsiella ictaluri infection and that prolonged consumption of Romet-medicated feed may suppress antibody production.     

Vaccination against feline viral rhinotracheitis in kittens with maternally derived feline viral rhinotracheitis antibodies

The efficacy of a modified live-virus intranasal vaccine and a killed-virus adjuvanted parenteral vaccine in inducing protective immunity against feline viral rhinotracheitis (FVR) was evaluated in kittens with and without maternally derived FVR antibodies. The intranasal vaccine was given as a single dose to kittens 5 weeks old, and the parenteral vaccine was administered in 2 doses at 5 and 7 weeks of age. Seroconversion was delayed for 5 to 10 days in kittens with maternally derived antibodies, but occurred in all vaccinated kittens by 8 weeks of age. When virulent FVR virus was given, both vaccines provided satisfactory protection against disease but did not prevent infection. The results indicated that the modified live-virus intranasal vaccine or the killed-virus adjuvanted parenteral vaccine can be used successfully in kittens with residual maternally derived FVR antibodies.     

Evaluation of biochemical evidence of congenital nutritional myopathy in two-week prepartum fetuses from selenium-deficient ewes

Muscle damage attributable to selenium (Se)/vitamin E deficiencies is known to develop at birth or later in lambs. The purpose of this study was to determine whether and when muscle damage develops in utero. Thirty pregnant ewes maintained on Se-deficient forages from birth were allotted to 3 equal groups. Half of each group was given a single IM injection of 0.056 mg of Se/kg of body weight, 1 month before parturition. At 3 weeks before parturition, cesarean section-derived fetuses from Se-deficient ewes did not have evidence of muscle damage. At 2 weeks before parturition, fetuses from Se-deficient ewes had biochemical evidence of congenital nutritional myopathy, as evidenced by low blood Se concentration (P less than 0.05) and by increased plasma creatinine kinase (P less than 0.001) and lactate dehydrogenase (P less than 0.01) activities, compared with fetuses from Se-treated ewes. Thus, for optimal protection of fetuses and newborn lambs in Se-deficient areas, Se should be administered to ewes at least 1 month before parturition.     

Cimetidine for treatment of melanomas in three horses

Cimetidine, an H2 histamine antagonist, was used in the clinical management of progressive, multifocal melanomatosis in 3 adult gray horses. Prior to treatment, the tumors had increased rapidly in size and number in 2 horses (duration of 6 and 27 months, respectively) and slowly in the third horse (duration of 48 months). All 3 horses were treated with cimetidine (2.5 mg/kg of body weight, PO, q 8 h) for 2 months to 1 year. During treatment, the number and size of the melanomas decreased substantially (50 to 90%). The progression of the disease was halted in 2 horses and controlled in the third horse, which is still being treated with cimetidine (1.6 mg/kg, PO, q 24 h). The horses in which treatment was terminated have not been treated for 31 and 41 months, respectively, during which time the melanomas have not increased in number or size.     

Clinicopathologic findings resembling hypoadrenocorticism in dogs with primary gastrointestinal disease

Nine dogs with primary gastrointestinal disease had clinical and laboratory findings resembling hypoadrenocorticism. The dogs had histories of anorexia, weakness or lethargy, diarrhea, vomiting, and weight loss. Hypothermia, dehydration, and emaciation also were detected on physical examination. Hyponatremia, hyperkalemia, and abnormally low Na/K ratios were found on laboratory evaluation, but results of ACTH-response tests were not compatible with hypoadrenocorticism. The primary diagnoses were trichuriasis and salmonellosis in 2 dogs, trichuriasis in 5 dogs, and perforated duodenal ulcer in 2 dogs. Most dogs responded to medical or surgical treatment of their primary gastrointestinal disease, and the original electrolyte abnormalities resolved. These findings emphasize the importance of the ACTH-response test in the diagnostic evaluation of dogs with clinicopathologic findings similar to those of hypoadrenocorticism.     

The influence of empty body weight and mature weight of the genotype on energy density of empty body gain in growing lambs

From data reported by authors who had serially determined the chemical composition of the empty body of growing lambs of a wide range of genotypes, the energy density of empty body gains (E/G) at intervals from 20 to 50 kg empty body weight (EBW) were estimated. Energy density of empty body gain was related to the EBW of these lambs and to an approximation of the mature weight for the genotype (MW) obtained from a separate data set. The addition of MW to the function relating E/G to EBW increased the r2 from .793 to .940 and reduced the residual standard deviation from .550 to .300 Mcal/kg. Combining EBW and MW as predictors of E/G provided the following function: E/G = 5.718 + .093 (EBW) - .036 (MW). Energy density of empty body gain was approximately constant across all genotypes when comparisons were made at a constant EBW/MW. Thus, both EBW and mature weight of the genotype are closely related to E/G and should be considered important for accurately predicting net energy of gain requirements for growing lambs.