EFFECT OF DAILY WEATHER CONDITIONS ON BLOAT IN CATTLE FED FRESH ALFALFA

Abstract

Daily weather records from seven consecutive growing seasons and daily nitrogen levels in alfalfa herbage from the last four seasons were studied in order to identify relationships with bloat in cattle. The cattle tended to bloat as a group rather than independently. Bloat occurred on at least 30% of the days observed in each season but in the two driest, warmest years the percentages increased to 46 and 63. Days on which bloat occurred were preceded by lower maximum and minimum temperatures on the average than days on which bloat did not occur but the difference in temperature was small. On a daily basis no differences were observed between days of bloat and no bloat in hours of sunshine, temperature range, precipitation, solar radiation flux or potential evapotranspiration. The concentration of total nitrogen, soluble nitrogen and soluble protein nitrogen in the feed was higher on days when bloat occurred than when it did not occur. Key words: Pasture bloat, alfalfa, cattle, climate, evapotranspiration