Use of narcotic antagonists to modify stereotypic self-licking, self-chewing, and scratching behavior in dogs

We evaluated 2 narcotic antagonists, naltrexone and nalmefene, for treatment of refractory self-licking, self-chewing, and scratching behavior in dogs. Eleven dogs with various irritative or pruritic disorders were medicated with naltrexone (1 mg/kg of body weight, sc) or nalmefene (1 to 4 mg/kg, sc), after a period of control observation during which the dogs had not been medicated. The time for which the dogs were involved in self-licking, self-chewing, or scratching was determined retrospectively by analysis of videotapes. The rates of involvement in either activity before and after treatment were calculated and compared statistically. Treatment with a narcotic antagonist significantly reduced the time spent self-licking, self-chewing, or scratching in 7 of 11 dogs, was partially effective in 3 dogs, and was ineffective in one dog. Dogs with acral lick dermatitis responded most to treatment.     

Seroprevalence of Toxoplasma gondii in mainland and sub-Antarctic New Zealand sea lion (Phocarctos hookeri) populations

AIMS: To investigate the seroprevalence of antibodies to Toxoplasma gondii in New Zealand sea lions (Phocarctos hookeri), as a potential contributor to reproductive failure.

METHODS: Archived sera were sourced from New Zealand sea lions from two recolonising mainland populations in the Otago Peninsula (n=15) and Stewart Island (n=12), as well as a declining population at Enderby Island (n=28) in the New Zealand sub-Antarctic. Sera were tested for antibodies to T. gondii using a commercially available ELISA (with samples considered positive if the sample to positive ratio was?>30%), and latex agglutination test (LAT; with titres ≥1:32 considered positive). Western blot analysis was used to validate the results of a subset of 14 samples.

RESULTS: Five samples from sea lions in mainland locations were confirmed positive for antibodies to T. gondii. Two adult females exhibited high LAT antibody titres (min 1:2048, max 1:4096) on both occasions when sampled 1 and 2 years apart, respectively. No animals from Enderby Island were seropositive.

CONCLUSIONS: Toxoplasma gondii infection is unlikely to be a major contributor to poor reproductive success in New Zealand sea lions. However, continued surveillance is pertinent to assess subclinical and clinical impacts of the parasite on these threatened populations. The commercial tests evaluated here, with further species-specific threshold refinement could provide a fast, inexpensive and reliable indicator of T. gondii exposure in New Zealand sea lions.     

Severity and persistence of footrot in Merino sheep experimentally infected with a protease thermostable strain of Dichelobacter nodosus at five sites

Objective To test the hypothesis that ovine footrot associated with a thermostable protease strain of Dichelobacter nodosus undergoes self cure or is sustained as an annually recurring disease, depending on the environment.
Design and procedure Forty Merino sheep from a single blood line were infected with a protease thermostable strain of D nodosus a t each of five sites in Western Australia. Footrot lesions and microscopic evidence of D nodosus were recorded every fortnight for 2.5 years, supplemented by laboratory culture. Rainfall, soil and air temperature, pasture quantity and composition and soil types were also recorded. Flocks that apparently self cured were relocated to a more favourable site for footrot in the final spring season.
Results The maximum prevalence of feet with clinical footrot lesions was 80.6, 1.3, 14.4, 3.8 and 88.1% at the five sites. Severe footrot occurred for three consecutive spring seasons at one site that had clay loam soil and at least 3500 kg/ha total pasture dry matter annually. However, the infection was asymptomatic for up to 10 weeks between outbreaks. D nodosus was isolated from flocks for 2.5 years at only two sites, although there was microscopic evidence of the organism at other sites in the final year. A thermolabile variant (strain U6) of D nodosus was isolated from the two sites where footrot persisted.
Conclusion Depending on time and location, ovine footrot induced by a protease thermostable strain of D nodosus either self cured or persisted as annual outbreaks interspersed with periods of asymptomatic infection.     

The use of dextromethorphan to treat repetitive self-directed scratching, biting, or chewing in dogs with allergic dermatitis

OBJECTIVE: To evaluate the efficacy of oral dextromethorphan in dogs with a repetitive behavior problem (self-licking, self-chewing, and self-biting associated with chronic allergic dermatitis). ANIMALS: Fourteen dogs with chronic allergic dermatitis were enrolled in the study. Twelve dogs completed the study. PROCEDURE: The dogs were treated for 2 weeks each with dextromethorphan (2 mg/kg BID) and placebo in a randomized, double blind, crossover designed study. A dermatology score, including an assessment of affected areas of the integument and the level of self-directed behavior, was generated before and following each 2-week phase of the study. Owners were required to record daily the amount of time they spent with their dog and the amount of time that the dog was observed to be engaged in any of the specified self-directed behaviors. RESULTS: The percent of the observed time that the dogs were reported to be involved in self-directed behaviors was significantly less during the 2-week active drug treatment phase. The pruritus score component of the dermatology score also was significantly less during the active treatment phase. In addition, a dermatologist-rated global assessment was more favorable in 11 of 12 dogs following the active treatment phase. CONCLUSIONS: Dextromethorphan significantly reduces the percentage of time that allergic dogs spend self-licking, self-chewing, and self-biting. CLINICAL RELEVANCE: Dextromethorphan may be a useful adjunct in the management of self-directed behaviors associated with allergic dermatitis and possibly in other repetitive behaviors as well.     

Effect of dietary protein content and tryptophan supplementation on dominance aggression, territorial aggression, and hyperactivity in dogs

OBJECTIVE: To evaluate the effect of high- and low-protein diets with or without tryptophan supplementation on behavior of dogs with dominance aggression, territorial aggression, and hyperactivity. DESIGN: Prospective crossover study. ANIMALS: 11 dogs with dominance aggression, 11 dogs with territorial aggression, and 11 dogs with hyperactivity. PROCEDURE: In each group, 4 diets were fed for 1 weeks each in random order with a transition period of not < 3 days between each diet. Two diets had low protein content (approximately 18%), and 2 diets had high protein content (approximately 30%). Two of the diets (1 low-protein and 1 high-protein) were supplemented with tryptophan. Owners scored their dog's behavior daily by use of customized behavioral score sheets. Mean weekly values of 5 behavioral measures and serum concentrations of serotonin and tryptophan were determined at the end of each dietary period. RESULTS: For dominance aggression, behavioral scores were highest in dogs fed unsupplemented high-protein rations. For territorial aggression, [corrected] tryptophan-supplemented low-protein diets were associated with significantly lower behavioral scores than low-protein diets without tryptophan supplements. CONCLUSIONS AND CLINICAL RELEVANCE: For dogs with dominance aggression, the addition of tryptophan to high-protein diets or change to a low-protein diet may reduce aggression. For dogs with territorial aggression, tryptophan supplementation of a low-protein diet may be helpful in reducing aggression.     

Thermochronometry reveals headward propagation of erosion in an alpine landscape

Glacial erosion of mountain ranges produces spectacular alpine landscapes and, by linking climate with tectonics, influences a broad array of geophysical phenomena. Although the resultant landforms are easily identified, the timing and spatial pattern of topographic adjustment to Pleistocene glaciations remain poorly known. We investigated topographic evolution in the archetypal glacial landscape of Fiordland, New Zealand, using (U-Th)/He thermochronometry. We find that erosion during the past 2 million years removed the entire pre-Pleistocene landscape and fundamentally reshaped the topography. Erosion focused on steep valley segments and propagated from trunk valleys toward the heads of drainage basins, a behavior expected if subglacial erosion rate depends on ice sliding velocity. The Fiordland landscape illustrates complex effects of climate on Earth's surface morphology.     

Dermatosparaxis in two White Dorper lambs

Abstract

CASE HISTORY AND CLINICAL FINDINGS: Two White Dorper lambs from the North Island of New Zealand, 2 and 4 weeks of age, were presented with large skin flaps hanging from the flanks, separation of skin from the subcutis over mobile joints, and de-gloving injuries of the limbs and tail. The lambs were subject to euthanasia on humane grounds.

PATHOLOGICAL FINDINGS: Large skin tears with associated haemorrhage, periarticular S/C oedema and generalised skin fragility were observed in both lambs at post-mortem examination. Histology of the affected skin revealed diffuse hyalinisation of dermal collagen compared with control lambs, protein-filled peri-adnexal clefts and areas of deep dermal and S/C granulation tissue consistent with previous separation of skin from the subcutis. Analysis of hair follicles, collected from one of the lambs, using a commercially available genetic test in Australia was consistent with the lamb being homozygous for the mutation responsible for ovine dermatosparaxis.

DIAGNOSIS: Likely dermatosparaxis.

CLINICAL RELEVANCE: These findings strongly suggest that the mutation responsible for dermatosparaxis in White Dorper sheep is present in New Zealand. Dermatosparaxis should be considered when investigating skin fragility in lambs with White Dorper genetics. Confirmation of the disorder is possible through genetic analysis of hair follicles.