Physical characteristics of the XXXX teat canal and their influence on susceptibility to streptococcal infection.

@entity281 @entity291 @entity5967
Physical characteristics of the @entity291 teat canal were examined for their influence on susceptibility to intramammary @entity281 . All quarters of 18 @entity291 were inoculated with 2 x 10(5) cfu @entity5967 (Trial 1) and 20 @entity291 with 10(5) cfu Str. uberis (Trial 2) 3-4 mm into the teat canal every 3 d for 12 d. Incidence of @entity281 was similar for both pathogens, 30/72 (42%) in Trial 1 and 32/80 (40%) in Trial 2. Logistic regression analysis showed that probability of @entity281 by Str. agalactiae increased significantly with an increase in quarter peak flow rate (P < 0.05) whereas probability of @entity281 increased for Str. uberis with a decrease in teat canal length (P < 0.05). A significantly higher (P < 0.001) incidence of @entity281 by Str. uberis was observed in quarters that contained a low wet weight (< 1.8 mg) of removable keratin compared with those that contained > 1.8 mg keratin, but there was no correlation between weight of keratin and length of the teat canal. Infections by Str. uberis took significantly less (P < 0.05) time to show a rise in somatic cell count above 7.5 x 10(5) cells/ml than Str. agalactiae. The results provide evidence that these pathogens use different mechanisms to pass through the teat canal.
