Know more

Original experimental approaches and meta-analysis to determine the effect of pre-grazing pasture mass

In Western Europe, grazing represents 3 to 10 months in the feeding system of dairy cows. Extending the grazing season (winter-autumn) is recognized to lower costs of production and to increase sustainability of dairy systems. This however implies atypical grazing conditions, with particularly low sward height or low pre-grazing pasture mass, that can affect negatively intake and performance. Under rotational grazing system, the effect of pre-grazing pasture mass on intake is not well described and contradictory, in relation to the range in methodologies across countries.
The challenge is to better define grazing conditions and to predict accurately pasture intake and performance of dairy herds during all the grazing season and whatever grazing and feeding management.

Results for predicting intake throughout the year in all grazing systems

• The effect of an increase in pasture mass (kg DM/ha) on intake and milk production is positive, null or negative when pasture mass is determined (i.e. pasture allowance is defined) at ground level, above 2-3 cm or above 5 cm from the ground, respectively. This was demonstrated experimentally and from a meta-analysis of international literature.
• Pasture allowance expressed above 2-3 cm from ground level is a robust criteria defining actual pasture availability for cows because it is independent of pasture mass in a wide range of pasture mass.
• Very low pasture mass always limits pasture intake, as under set-stocking grazing.

Lucio Pérez-Prieto has obtained those results during his PhD thesis (2009-2012)

For further information

Pérez-Prieto, L. A., Delagarde, R. (2013). Meta-analysis of the effect of pasture allowance on pasture intake, milk production, and grazing behavior of dairy cows grazing temperate grasslands . Journal of Dairy Science, 96 (10), 6671-6689. (DOI)

Pérez-Prieto L.A., Peyraud J.L., Delagarde R. (2013) Does pre-grazing herbage mass really affect herbage intake and milk production of strip-grazing dairy cows? Grass and Forage Science, 68 (1), 93-109. (DOI)

Pérez-Prieto L.A., Delagarde R. (2012) Meta-analysis of pre-grazing pasture mass effect on pasture intake, milk production, and grazing behavior of strip-grazing dairy cows. Journal of Dairy Science, 95 (9), 5317-5330. (DOI)

Pérez-Prieto L.A., Peyraud J.L., Delagarde R. (2011) Pasture intake, grazing behaviour and performance of dairy cows grazing low-mass pastures at three daily allowances in winter. Livestock Science, 137, 151-160. (DOI)

Pérez-Prieto L.A., Peyraud J.L., Delagarde R. (2011) Substitution rate and milk yield response to corn silage supplementation of late-lactation dairy cows grazing low-mass pastures at 2 daily allowances in autumn. Journal of Dairy Science, 94 (7), 3592-3604. (DOI)

Contact

Rémy Delagarde, Dairy system team  (remy.delagarde[at]rennes.inra.fr)