PREDICTION OF BLOAT SUSCEPTIBILITY OF COWS FROM BAND 4 PROTEIN-CONCENTRATION IN SALIVA COLLECTED BY 2 METHODS

The concentration of a salivary protein, Band 4, was determined in sam ples of saliva from 76 lactating cows aged from 2 to 7 years when remo ved from pasture. Saliva was collected from the mouth (using a bit) on one occasion and at the cardia on a separate occasion. Cows were clas sified to be of high (HS) or low (LS) susceptibility to bloat, and a b reeding value (BV) for bloat calculated from bloat scores recorded dur ing periods of bloat challenge was available for 67 cows. The concentr ations ns of Band 4 for HS and LS cows, respectively, averaged 5.46 an d 9.02 mug/ml (SED = 1.26) in the bit collection and 5.05 and 6.78 mug /ml (SED = 1.22) in the cardial collection. Bit and cardial Band 4 con centrations were correlated (P < 0.05) but only 23% of the variation i n bit Band 4 was explained by cardial Band 4. Bloat BV and Band 4 conc entration in either bit or cardial collection were poorly correlated, suggesting that Band 4 concentration in a single sample of saliva coll ected from cows off pasture was not useful as a predictor of bloat sus ceptibility.