Interaction of operant behaviour and autonomic thermoregulation in the domestic fowl.

1. Domestic fowls were trained to peck a disc in order to receive a limited thermal reinforcement. 2. When subsequently tested, their use of the operant response was a function of ambient temperature, decreasing from 0 to 24 degrees C and rising again steeply from 28 to 42 degrees C. 3. Under cool conditions changes in rate of heat production were of major significance in maintaining homeothermy, whilst in the heat the operant response was used in preference to, or in addition to, thermal panting. 4. Data from the behavioural studies, together with those on autonomic effector mechanisms, indicate that optimal thermal conditions for the fowl are likely to be attained at 22 to 24 degrees C.     

A field trial with a multicomponent inactivated respiratory viral vaccine.

An inactivated virus vaccine containing strains of parainfluenza type 3 (PI3), bovine adenovirus type 3, reovirus type 1, bovine virus diarrhoea (BVD) and infectious bovine rhinotracheitis (IBR) viruses was tested in a group of 58 calves reared in a semi-intensive management system. Following vaccination, 1/30, 14/30 and 17/30, showed significant rises in antibody titre to reovirus type 1, adenovirus type 3 and IBR respectively. None of the animals showed significant serological response to PI 3 and BVD. In the control group, 2/28, 1/28, 6/28 and 3/28 developed antibody responses to reovirus type 1, BVD, adenovirus type 3 and IBR respectively. Microbiological examination revealed the presence of a wide variety of commensal bacteria and Mycoplasma bovirhinis in both groups. Analysis of the records of clinical examinations indicated that the respiratory tract infections occurred among the calves at between 50 and 80 days after arrival at the farm, and that there was no significant difference between the test and the control groups. A number of animals had maternal antibodies to the various components of the vaccine present before the trial commenced and these antibodies appeared to interfere with the subsequent serological response to the antigen challenge. The vaccination schedule recommended by the manufacturer does not entirely circumvent this problem.     

THE NEW SOUTH WALES MASTITIS CONTROL PROGRAM

Bacteriological examinations were made on quarter samples from cows in 35 herds over a 3 year period to monitor the response in a mastitis control program. Initially, Staphylococcus aureus predominated in 32 of the herds and the mean herd prevalence was 26%. The control measures halved this rate but there was considerable variation in response between herds. The decline occurred rapidly and there was a significant reduction (P less than 0.01) by 3 months. Streptococcus agalactiae predominated in 3 herds and the overall infection rate was 4.9%. Control measures eliminated the infection completely from most herds but reinfection occurred in 2 herds. The greatest decline occurred in the first 6 months and was significant (P less than 0.05). The measures had little effect upon Str. uberis and Str. dysgalactiae which remained fairly consistently at low levels. Initially, strains of Staph. aureus resistant to penicillin were dominant in most herds. In a minority of herds strains resistant to streptomycin predominated and in these herds there was a concurrent resistance to penicillin. These patterns did not change greatly over the control period. Resistance by Str. agalactiae to streptomycin occurred in most herds at the start of the program.     

Congenital unilateral cleft of the soft palate in six dogs

Unilateral cleft of the soft palate occurs sporadically in dogs, and there are few reports in the veterinary literature regarding its aetiology and management. This report describes six dogs with the condition. The dogs' primary presenting problem was rhinitis. The defects were successfully repaired using a two-layer closure technique with absorbable suture in five of the cases. Surgical correction was not performed in the remaining case.