Sward and milk production response to early turnout of dairy cows to pasture in Finland

Summary

The timing of turnout is an important factor affecting the grazing management of dairy cows. However, its consequences are not well known in the short grazing season of northern Europe. Thus, the effect of the turnout date of dairy cows to pasture on sward regrowth, herbage mass production and milk production was studied in two experiments, 1) a grazing trial with 16 Holstein-Friesian dairy cows and 2) a plot trial where the treatments simulated the grazing trial. The treatments were early turnout (1 June) and normal turnout (6 June). Early turnout decreased the annual herbage mass (HM) production in the plot trial (P=0,005), but due to a higher average organic matter (OM) digestibility (P<0,001) the difference in digestible OM yield was not significant (P=0,14). Similarly, early turnout decreased the mean pre-grazing HM in the grazing trial. The differences in HM quantity and quality between early and normal turnout occurred mainly in late June and early July and thereafter levelled out. Average post-grazing sward heights were lower for early turnout, indicating better HM utilization. There were no differences in yields of milk, milk fat or milk protein (P>0,05). Although early turnout had no effect on milk yields it meant easier management of pastures.