Movement of bacteria and nutrients from pit latrines in the boundary waters canoe area wilderness

In the Boundary Waters Canoe Area Wilderness, the movement of fecal bacteria, N, and P from pit latrines was studied, as well as the effectiveness of peat latrine liners in reducing this movement. When latrines are constructed where only a thin layer of permeable soil overlies bedrock or other impermeable material, fecal bacteria can be carried considerable distances by subsurface flow. Lining latrine pits with acid peat appears to reduce bacteria transport. Most soils strongly adsorb P and prevent its movement. In this study no movement of P from latrine pits was seen except at one site with very sandy soil. In such soil a peat liner appears to be of some value, if a peat with a high P adsorption capacity is used. A peat liner should be viewed as an additional protection against P and bacteria movement rather than as a substitute for proper soil conditions. Latrines should not be built in thin, rocky soils. Nitrogen appears to move readily from toilet pits, regardless of soil type or presence of peat liners. But, because of dilution, N is not likely to have a discernible impact on water quality.     

Successful treatment of distichiasis in a cat using transconjunctival electrocautery

A 2-year-old male castrated Domestic Short-haired cat presented to the Ophthalmology Service at the Matthew J. Ryan Veterinary Hospital at the University of Pennsylvania for evaluation of chronic bilateral ocular discharge and blepharospasm. Initial ophthalmic examination revealed severe conjunctivitis and keratitis and the presence of upper eyelid distichiae bilaterally. Initial therapy for suspected feline herpesviral infection provided moderate, but not complete, resolution of the clinical signs. Over the subsequent year, the cat suffered from recurrent, severe, ulcerative keratitis in both eyes despite appropriate medical therapy. Approximately 13 months after the initial presentation, the distichiae were surgically removed using transconjunctival electrocautery, which resulted in complete resolution of the clinical signs. This report documents bilateral distichiasis in a cat, a condition that is considered rare in this species.     

Effects of social stress on the toxicity of malathion in young chickens

Thirty-eight 7-week-old white leghorn chickens of two strains (high and low antibody response to sheep erythrocytes) were divided into groups for exposure to high and low levels of social stress. They were then challenged orally with a toxic dose of the organophosphate insecticide malathion (250 mg/kg body weight) and evaluated 60 min later for muscarinic signs (diarrhea, lacrimation, respiratory secretions), nicotinic signs (muscle weakness), plasma cholinesterase activity, and brain acetylcholinesterase activity. A significant correlation was shown between clinical and biochemical indices of organophosphate toxicity. The correlation between social stress and malathion toxicity was less well defined. Chickens with low antibody response preexposed to high social stress were most resistant to organophosphate toxicity.     

Heartworm disease manifested by encephalomyelitis and myositis in a dog

A 2-year-old Boston Terrier was referred because of depression and hindlimb and tail paresis. Clinical examination and serum biochemical analysis resulted in a diagnosis of encephalomyelitis and myositis. Results of testing for Dirofilaria immitis were positive. Gross and histologic examination revealed an aberrant adult heartworm infection resulting in thrombosis of the femoral artery and multiple muscular branches, with subsequent muscle necrosis and inflammation in one hindlimb. Additionally, an unusual larval-tissue interaction to microfilariae yielded a multifocal encephalomyelitis in the brain and spinal cord.     

Escherichia coli challenge in chickens selected for high or low antibody response and differing in haplotypes at the major histocompatibility complex.

Relative sensitivity to Escherichia coli challenge was evaluated in white leg-horn chickens that had been selected for high antibody (HA) or low antibody (LA) response and that differed in haplotypes at the major histocompatibility complex (MHC). Assessments were made of relative body-weight change and of heart and air-sac lesions after inoculation of 10(6), 10(5), or 10(4) E. coli via the posterior thoracic air sac. As has previously been reported, chicks from line HA were more sensitive to E. coli than those from line LA. Lesion scores were 1.58 +/- 0.12 in line HA and 1.02 +/- 0.12 in line LA (mean +/- S.E.), and ranged from 0.99 +/- 0.14 with the lowest dose of E. coli to 1.79 +/- 0.15 for the highest dose. Relative body-weight change to 72 hours after inoculation was greater in line LA (7.5 +/- 0.5) than in line HA (4.4 +/- 0.8). There was no apparent resistance or susceptibility conferred to chickens in either the HA or LA genetic background as a result of haplotypes present at the MHC.     

Control of induced infestations of adult Amblyomma hebraeum with sustained release ivermectin

The efficacy of ivermectin, administered in a sustained release formulation by intraruminal pumps at approximate daily dose rates of 20, 40 and 60 micrograms/kg, was evaluated in 16 cattle against induced infestations of 3 strains of adult Amblyomma hebraeum. Engorged female ticks were mass-measured and incubated, and reproductive data recorded. There was an increase in mortality of male and female ticks compared to that of controls with increasing daily dose of ivermectin, and a decrease in the number of ticks engorging. Ticks fed on ivermectin-treated cattle had a smaller mass when engorged and laid smaller egg masses, both absolutely and as a proportion of engorged mass. Index of reproduction was reduced 100% at 60 micrograms/kg/day, greater than 99% at 40 micrograms/kg/day and 96% at 20 micrograms/kg/day. Differences occurred between the 3 strains of A. hebraeum used in the study, especially with regard to engorged mass and reproductive variables. Practical implications of the application of sustained release ivermectin for the control of A. hebraeum, specifically with reference to heartwater (Cowdria ruminantium), are discussed.     

Adaptation of a fluorescent immunoassay for canine haptoglobin

The development and adaptation of a fluorescent immunoassay for determining changes in canine haptoglobin levels is described. Levels of canine haptoglobin determined by the fluorescent immunoassay from a group of healthy dog sera (68.0 mg/dl) compared favorably to the haptoglobin levels determined by a spectrophotometric method (74.5 mg/dl). The fluorescent immunoassay offered several advantages over currently used methods for determining levels of canine haptoglobin in serum.     

Influence of dietary forage and energy intake on metabolism and acyl-CoA synthetase activity in bovine ruminal epithelial tissue.

Twenty calves (7 mo old) were blocked by breed, sex, and weight into five groups of four calves and randomly assigned to either a 90% forage (alfalfa) or a 90% grain (50% sorghum and 50% wheat) diet fed at one (1M) or two (2M) times NEm for 140 d. Samples of ruminal epithelial tissue were collected from the anterior ventral sac, and papillae were cut free by hand and used for in vitro incubations and acyl-CoA synthetase assays. Substrates were acetate (90 mM), propionate (60 mM), butyrate (30 mM), and glucose (20 mM). Net productions of beta-hydroxybutyrate and acetoacetate from acetate were greater (P less than .01) with the 2M feeding; however, 14CO2 production from acetate was greater (P less than .05) with the grain diet. Net production of lactate (P = .09) and pyruvate (P less than .01) from propionate increased with the 2M feeding, whereas net lactate production from glucose decreased (P less than .01). Uptakes of VFA were similar with 1M and 2M feeding and were about 10-fold greater than uptakes of glucose. Production of 14CO2 from propionate was two- to fivefold greater than from acetate, butyrate, or glucose. Oxygen consumption was greater (P less than .01) with 2M feeding and unaffected by substrate. Activities of butyryl-CoA synthetase (nmol.mg of tissue-1.h-1) were greater (P less than .05) for animals consuming the forage diets. Addition of butyrate inhibited acetyl- and propionyl-CoA synthetase activity by 63 and 92%, respectively for all dietary treatments. Overall, metabolism of ruminal epithelial tissue tended to increase with the 2M feeding. Influence of dietary forage content on metabolism and activity of acyl-CoA synthetases was minimal, but the high-forage diet caused slight increases.