| Abstract: | dAim: To evaluate the effectiveness of a liquid formulation of monensin in reducing bloat score in milking cows grazing pasture. dMethods: AFriesian x Jersey crossbred herd which had been genetically selected for high bloat susceptibility since 1973 was used in this study. Two trials were conducted, each involving two groups of 15 cows, randomly allocated toTreated or Control groups.Trial 1 involved twice-daily administration of a novel liquid formulation of monensin given toTreated cows at morning and afternoon milkings. Trial 2 involved once-daily administration of the same product toTreated cows at the morning milking only. Control cows received no preven tative treatment. The total daily dose of monensin in each trial was 300 mgper cow, given in a total volume of 100 ml of liquid. Animals were scored for bloat twice-daily whilst grazing on white-clover/ryegrass or red-clover pastures. The scoring system used a scale of 0, 1, 1.5, 2, 2.5, or 3, representing scores of increasing bloat severity as assessed by palpation of abdominal pressure on the left and right sides of the cow. dResults: In Trial 1, severe bloat was recorded at 9 out of 23 scoring sessions.Twelve Control cows required therapeutic treatment for bloat on at least one day, compared to 3 cows in theTreated group (p=0.003). In Trial 2, severe bloat in 3 of 9 scoring sessions led to 8/15 Control animals requiring therapeutic treatment compared to 1/14 cows in theTreated group (p=0.02). dConclusions: Oral drenching with the liquid formulation of monensin tested was effective in reducing bloat score in milking cows grazed on pasture. |
