Restricting Time of Access to Large Round Bales of Hay Affects Hay Waste and Cow Performance

Simmental cows in the third trimester of gestation were used in 2 trials to determine the effects of time-restricted access to large round bales on cow performance and hay disappearance. In trial 1, highquality (127 relative feed value) hay was fed ad libitum (no time restriction) or access- restricted to 9, 6, or 3 h/d. In trial 2, average-quality (96 relative feed value) hay was fed ad libitum or access-restricted to 9 or 6 h/d. In both trials, 72 cows were blocked by BW and assigned to 12 pens resulting in 6 cows per pen and 3 or 4 pens per treatment. Each pen had adequate bunk space for 7 cows, and time was limited by gates that prevented access to feeders. Results of trial 1 indicated cows on all treatments gained BW with a linear (P < 0.01) and quadratic (P = 0.03) treatment effect favoring increased time of access. As time of access increased, hay disappearance increased linearly (P < 0.01) and quadratically (P < 0.01), as did manure production, both linearly (P = 0.002) and quadratically (P = 0.07). Hay waste increased linearly (P = 0.009) with increasing time of access. In trial 2, BW gains were not different across treatments. Hay disappearance, manure production, and fecal output all increased linearly (P < 0.01) with increasing time of access. In both trials, N, P, and K outputs followed the trend of manure output and increased linearly with increasing time of access. Restricting time of access to large round bales of hay reduced hay disappearance while maintaining acceptable levels of cow performance.