Ponies anticipated the restricted grazing time period and ate more quickly.
Cool season pastures can contain substantial amounts of non-structural carbohydrates (NSC). Research links over consumption of NSC by grazing horses to laminitis, especially when horses have an existing health condition (i.e. previous history of laminitis). Restricted grazing is a common solution to managing laminitic horses, however, little research has measured pasture intake during periods of restricted grazing. The goal of this project, conducted by researchers in England, was to determine the relative dry matter intake (DMI) of pasture by ponies allowed three hours of grazing time per day and un-restricted access to hay for the remainder of the day over a six week period.
Four ponies were used for the study and were turned out daily in the afternoon into a mixed grass clover pasture. When not grazing, ponies were housed in individual stalls with un-restricted access to water and mixed grass hay. Pasture samples were taken to determine quality and pasture dry matter intake were determined from change in pony body weight over the three hour grazing period. Intake of hay was determined daily for each pony.
Ponies gained an average of 0.7 pounds per day and total daily dry matter intake over the six week period remained constant averaging 2% body weight per day. The proportion of total daily dry matter intake accounted for by grazing rose from 22% to 49% by week 6 representing 0.49 and 0.91% of body weight in weeks one and six, respectively. In conclusion, the increase of 0.49% to 0.91% body weight suggests that as the trial progressed, restricting grazing time for ponies became increasingly less effective in reducing pasture intakes.
In other words, the ponies anticipated the restricted grazing time period and as a result, ate more quickly as the trial progressed.