Effect of density on brood size in noble crayfish,Astacus astacus L., subjected to indoor rearing conditions*

Abstract. The effects of density, cover, and individual versus communal holding on brood size and female survival during the breeding period were examined in a large-scale experiment, involving 3591 mature noble crayfish, Astacus astacus L., females. Crayfish density during both mating/spawning and winter incubation had major effects on egg survival. In the high density experiment (67 and 44 individuals per m² during mating/spawning and winter incubation respectively) mean pleopod egg number in April was 18-20. Lowering the density to 50 during mating/spawning (still 44 individuals per m² during winter incubation) gave mean pleopod egg numbers of 31-38. In the low density experiment (50 and 33 individuals per m² during mating/spawning and winter incubation) mean pleopod egg numbers were 44-46. Egg-bearing females held in individual compartments with perforated bottom had a mean pleopod egg number of 25. Female survival during winter incubation was high, ranging from 91.8 to 98.3%. Covering the basins had no distinct effect on egg and female survival. In Astacus astacus culture we recommend that crayfish density should not exceed about 50 individuals per m² during mating/spawning and about 33 individuals per m² during winter incubation.     

Surgical results and fertility following correction of vesicovaginal reflux in mares

Objective To evaluate the surgical results and fertility of mares bred at various intervals relative to surgical management of urovagina. Design Sixty-one mares underwent surgery to correct vesicovaginal reflux. Surgery was performed at varying times relative to breeding and postoperative fertility was evaluated. Results Five mares were lost to follow-up and a further four were electively not bred. Of the remaining 52 mares, seasonal pregnancy and live foaling rates were 67% (35/52) and 54% (26/48), respectively. When mares were bred in the same cycle as the surgery, the first cycle following surgery, the second cycle following surgery or the following breeding season after surgery the seasonal pregnancy rates were 89% (8/9), 63% (10/16), 67% (2/3) and 63% (15/24), respectively. After censoring four mares that died of natural causes pre-foaling, the foaling rates were 88% (7/8), 50% (7/14), 0% (0/3), 52% (12/23), respectively. All mares bred in the same cycle as surgery or in the next cycle were bred once only that season, so the pregnancy rate per cycle of 72% (18/25) was identical to the seasonal pregnancy rate. Conclusions Good fertility (comparable to a normal population of mares) was achieved following surgery and the results suggest that delaying breeding until the following breeding season is not necessary. In addition, breeding in the same cycle as surgical repair is a previously unreported technique that should be considered to maintain a yearly foaling interval.     

Distal luxation of the patella in a horse

A 19-year-old Thoroughbred gelding presented with sudden onset, non-weight bearing lameness in the right hindlimb. Radiography confirmed distal luxation of the patella, which was replaced into its normal anatomical location under general anaesthesia. There were no pathological sequelae noted on follow-up examination 9 months after the initial injury. To our knowledge, this is a rare manifestation of patellar luxation, only reported once previously in the equine literature.     

Antimicrobial stewardship in equine practice

Antimicrobial stewardship involves the judicious use of antimicrobials balanced against the requirement to treat the presenting clinical condition. The same mandate and principles as discussed in human medicine and other veterinary disciplines are relevant to equine practice. This brief review will focus on available resources for equine practitioners, emerging perspectives on antimicrobial use and stewardship, and opportunities for more effective antimicrobial use in equine practice. There is a need for improved client education, availability of faster and more accurate techniques for identification and sensitivity testing of bacterial pathogens, and the development of novel agents.     

Determination of the dosage of clomipramine for the treatment of urine spraying in cats

OBJECTIVE: To determine the optimal dosage of clomipramine for the treatment of urine spraying in cats. DESIGN: Randomized controlled multicenter clinical trial. ANIMALS: 67 neutered cats. PROCEDURE: Cats with a minimum 1-month history of spraying urine against vertical surfaces at least twice per week were randomly assigned to be treated with a placebo or with clomipramine at a dosage of 0.125 to 0.25 mg/kg (0.057 to 0.11 mg/lb), 0.25 to 0.5 mg/kg (0.11 to 0.23 mg/lb), or 0.5 to 1 mg/kg (0.23 to 0.45 mg/lb), p.o., every 24 hours for up to 12 weeks. Owners of all cats were given information on behavioral treatment and environmental modification. RESULTS: Prior to treatment, mean number of urine spraying events ranged from 0.9 to 1.3 urine spraying events/d for the 4 groups, and mean percentage of days with urine spraying events ranged from 62% to 69%. All 3 dosages of clomipramine were associated with significant reductions in frequency of urine spraying. Sedation was the most common adverse effect and was identified in 27 of the 50 cats treated with clomipramine; however, treatment was not discontinued in any cat because of sedation. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggest that compared with a placebo, clomipramine significantly reduces the frequency of urine spraying in cats in terms of the number of urine spraying events per day and the number of days with urine spraying events. For cats with urine spraying, the recommended initial dosage of clomipramine is 0.25 to 0.5 mg/kg, p.o., every 24 hours.     

Elimination behavior patterns of domestic cats (Felis catus) with and without elimination behavior problems

OBJECTIVE: To investigate the relationship of litter box location as it relates to cats' use of space in the house, elimination problems, and certain behaviors associated with elimination. SAMPLE POPULATION: 40 cats in single-cat house-holds with or without elimination behavior problems (20 cats/group). PROCEDURES: Camcorders were used to record the cats' behaviors at the litter box and other areas in which they eliminated during a 72-hour period. Use of space in the house was recorded by direct observation during 400 minutes of the 72-hour period. Elimination behaviors and other cat- and litter box-associated variables were compared between groups; litter box location with respect to inappropriate elimination was assessed. RESULTS: Litter box location did not differ between cats with and without elimination behavior problems. An inverse correlation was found between time spent sniffing and the distance of the litter box from the central core area. Cats with elimination problems spent significantly less time digging at the litter box than cats without elimination problems. There was no significant difference in the time spent pawing in litter box, sniffing, or covering excreta after elimination between the 2 groups of cats. CONCLUSIONS AND CLINICAL RELEVANCE: Times spent digging in litter boxes by cats with and without elimination problems have been determined, and data suggest that actual digging times could be used as a means to test for litter preference and litter aversion. This information may also be used to identify cats with litter aversion prior to the development of an elimination problem.     

Psychogenic colic in a horse

A 4-year-old mixed-breed gelding was presented with colic-type behavior of 5 days' duration that included pawing, looking at the flank area, and kicking and biting at the abdomen and flank when it was eating hay or grain. Medical evaluation did not reveal the cause of the "colic." During its stay in the hospital, the horse improved as regarded the colic-type behavior while eating, but resumed this behavior when it was able to see hay that it was not allowed to eat. It was determined that the persistent colic-type behavior developed as a result of the horse having been repeatedly displaced from its food by other horses. When the horse performed the colic-type behavior, the owner would remain with it and effectively protect it from competitors. The initial bout of colic may have been a result of true colic, psychosomatic colic secondary to stress, redirected aggression, or displacement activity.     

Antibiotic prophylaxis of lower respiratory tract contamination in horses confined with head elevation for 24 or 48 hours

Objective To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Design and Procedure Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocyte response, gross and cytologic characteristics of transtracheal aspirate and bacterial numbers in lower respiratory tract samples were compared with corresponding samples from two horses confined with heads elevated but not given penicillin. The efficacy of higher dose rates (20,000 IU/kg and 40,000 IU/kg) given before and during confinement with heads elevated for 24 hours was evaluated in experiment B. Results Treatment with procaine penicillin had no effect on the systemic leucocyte response or on the accumulation of inflammatory lower respiratory tract secretions at any of the dosing schedules evaluated. The number of bacteria isolated from trans-tracheal samples was reduced at 12 hours for treated horses in experiment A and at 24 hours for experiment B. β-haemolytic Streptococcus spp were not isolated from treated horses in either experiment. Bacterial species isolated from treated horses were predominantly Pasteurella and/or Actinobacillus spp, however, members of the family Enterobacteriaceaé and a Staphylococcus sp were isolated from treated horses. One treated horse in experiment A developed clinically apparent pulmonary disease. Conclusions The prophylactic administration of penicillin before or during confinement did not reliably reduce bacterial numbers or prevent the accumulation of purulent lower respiratory tract secretions in horses confined with their heads elevated. Numbers of β-haemolytic Streptococcus spp were reduced following treatment, suggesting that the repeated administration of procaine penicillin may have some merit as part of a strategy to prevent transport-associated respiratory disease. However, methods directed at minimising the duration of confinement with head elevation, augmentation of the clearance of accumulated secretions and prompt identification of animals in which airway inflammation has extended to the pulmonary parenchyma remain the best ways of minimising transport-associated respiratory disease.