BLOAT INVESTIGATIONS: RELATIONSHIP BETWEEN DAILY BLOAT INCIDENCE AND GRASS MINIMUM TEMPERATURES, DRY MATTER, AND CERTAIN PLANT NUTRIENT CONTENTS OF FORAGE

Abstract

Daily bloat incidence in 14 milking Jersey cows fed bloat-inducing alfalfa was recorded during 111 days of one grazing season. Bloat occurred on 86 days. A multiple regression equation was calculated with bloat incidence as the dependent variable and with grass minimum temperature and the percentage dry matter, nitrogen, phosphorus, potassium, sulphur, calcium, and magnesium contents of alfalfa as the independent variables. The average daily bloat incidence per cow was −.16+.51 N%. Nitrogen content of alfalfa accounted for 29% of the variation in bloat incidence but none of the other variables accounted for significant variation in bloat at the 5% level. Sulphur and dry matter were significantly correlated with bloat incidence but these correlations arose from associations between these two variables and nitrogen.