SEMEN WASTAGE AT A BOVINE ARTIFICIAL BREEDING CENTRE

The consequences of the use of swirl assessment at a bovine artificial breeding centre were studied. Data relating to the amount of semen discarded, fertility of accepted semen, the relationship between discard rates and age of bull and ejaculate number have been presented. The overall differences in fertility between semen with swirl ratings, 5, 6 and 7 were very small. About 50% of all ejaculates collected in the period considered were discarded at the first inspection. The discard rate tended to be greater in young and in older bulls. The discard rate was significantly greater (P less than or greater to 0.001) for second ejaculates. It was considered that a proportion of rejected semen may have been of good fertility. Semen wastage after freezing was low.     

LEPTOSPIRAL TITRES IN PIGS AFTER VACCINATION

Two groups of 8 pigs were vaccinated and given a booster vaccination 6 weeks later each with a commercial dual L. pomona and L. tarassovi killed vaccine. Serum from bloods collected before and up to 30 weeks after vaccination had agglutinating antibodies only after the 0ooster vaccination and then only with 1 vaccine. Titres persisted less than 8 weeks when tested against L. pomona but up to 16 weeks when tested against L. tarassovi at the 1:300 dilution and up to 20 weeks at the 1:100 dilution.     

Detection of parvoviruses in dogs using the hemagglutination test

The haemagglutination activity of the causal agent of canine parvovirosis is described. Out of the tested erythrocytes of pig, monkey, cat, horse, cattle, sheep, rabbit and guinea-pig, a positive reaction was recorded only in the erythrocytes of pig and monkey at the temperature of 4 degrees C. As a result of the examination of 20 faeces samples of hospitalized dogs by the method of haemagglutination reaction, a positive reaction typical of canine parvovirosis was obtained in 17 cases. The specificity of the reaction was confirmed by antiserum against the virus of panleucopenia of cat in the haemagglutination-inhibition test.