Matching grass supply to grazing patterns for dairy cows

Four groups of five spring-calving Holstein-Friesian cows were given a daily grass allowance in a strip-grazing system after either morning (AM; two groups) or afternoon (PM; two groups) milking over a 10-week period. The dry-matter (DNA) concentration of the grass tended to be higher after afternoon milking [AM, 178 vs. PM, 197 g DM (s.e.d. 5.32) kg(-1) fresh matter], and water-soluble carbohydrate concentrations were significantly higher [AM, 175 vs. PM, 204 g kg(-1) DM (s.e.d. 6.67)]. Although the total times spent grazing (AM, 461 vs. PM, 462 min day(-1)) were similar for both groups, cows receiving their allocation in the afternoon had a longer evening meal (>4 h duration) compared with those receiving their allocation in the morning (2-3 h), which also spent more time ruminating [AM, 454 vs. PM, 433 min day(-1) (s.e.d. 1,80)]. This short-term study demonstrated how a relatively simple change in management practice in strip-grazing systems could benefit milk yield and pasture utilization. This is because the DM and water-soluble carbohydrate contents of the herbage are higher in the evening than in the morning, and this is when grazing animals concentrate much of their daily grazing activity,.