Contents of Volume 57

Volume Contents

Contents of Volume 57     

Duration of corneal anesthesia following topical administration of 0.5% proparacaine hydrochloride solution in clinically normal cats

OBJECTIVE: To determine duration of corneal anesthesia following topical administration of 0.5% proparacaine hydrochloride solution in domestic shorthair (DSH) cats. ANIMALS: 20 clinically normal DSH cats. PROCEDURES: Baseline corneal touch threshold (CCT) was established by use of a Cochet-Bonnet aesthesiometer. Treatment consisted of a single 50-microL topical application of an ophthalmic preparation of 0.5% proparacaine solution to a randomly selected eye of each cat. The corneal touch threshold was assessed 1 and 5 minutes after application to the cornea and at 5- minute intervals thereafter for 60 minutes. RESULTS: Corneal sensitivity, as determined by Cochet-Bonnet aesthesiometry, was significantly reduced from baseline for 25 minutes following topical administration of ophthalmic proparacaine. Maximal anesthetic effect lasted 5 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: As determined by Cochet-Bonnet aesthesiometry, duration of anesthetic effects on the cornea induced by a single topical application of an ophthalmic preparation of 0.5% proparacaine solution in DSH cats is considerably shorter than the reported duration of corneal anesthesia in dogs.     

Erythrocyte pyruvate kinase deficiency in three West Highland white terriers in Ireland and the UK

Erythrocyte pyruvate kinase (PK) deficiency is described for the first time in three apparently unrelated West Highland white terriers (WHWT) from Ireland and the UK. All three dogs were diagnosed with markedly regenerative but persistent anaemia and had been treated for presumed immune-mediated haemolytic anaemia (IMHA) before hereditary erythrocyte PK-deficiency was confirmed by breed-specific DNA mutation analysis. This hereditary erythroenzymopathy causes haemolytic anaemia and affects several canine breeds with varying degrees of severity. Although eventually causing osteosclerosis, haemosiderosis and death, PK-deficient dogs can adapt to their anaemia for many years.PK-deficiency should be considered in anaemic WHWTs worldwide particularly in dogs with haemolytic anaemia where evidence for an immune-mediated, infectious or toxic underlying cause is lacking.     

Post-shearing management affects the seroincidence of Corynebacterium pseudotuberculosis infection in sheep flocks

Associations between the incidence of caseous lymphadenitis (CLA) in sheep and post-shearing management and environmental factors were examined in a prospective study. CLA incidence was measured in 126 groups of 1- and 2-year-old sheep in 70 Western Australian flocks selected from the prevalence of cull-for-age ewes with CLA lesions at abattoirs. CLA incidence was assessed using a CLA toxin ELISA. Dichotomous and polychotomous stepwise logistic regression methods were compared in examining the effects of management and environment on CLA incidence. Shower dipping sheep for ectoparasite control after shearing increased the odds of high CLA incidence by five to six times and keeping sheep under cover for 1 h or more after shearing increased the odds of being in high CLA incidence categories three-fold. The seroprevalence of existing CLA infection within each age group affected incidence more than did the overall slaughter-based flock estimate. This suggests that CLA spreads mostly within groups of sheep shorn together.     

Can timing of spawning explain the increase in egg size with female size in salmonid fish?

A common observation is that egg size increases with maternal size within populations. Several hypotheses have been proposed to explain this phenomenon. Most recently, it was suggested that the optimal egg size depends on female size due to correlations between (i) breeding time and egg size selection and (ii) female size and breeding time, and as such, the positive egg size–maternal size relationship represents an adaptive strategy. Here, we test the second of these two premises in two salmonid species, Atlantic salmon (Salmo salar) and coho salmon (Oncorhynchus kisutch) for which we have detailed breeding and egg size data. The body size of spawning females decreased throughout the season in coho salmon, but not in Atlantic salmon. Furthermore, we did not find a direct correlation between egg size and breeding time, which would also be expected if this premise was correct. Accordingly, breeding date does not appear to be as important as other factors in shaping among female differences in egg size.