1. Introduction Pastoreo Racional Voisin (PRV) – or Voisin Rational Grazing (VRG) – is a grazing management system developed by the French biochemist and farmer André Voisin (1903–1964) . His seminal work, La Productivité de l'Herbe (1957), translated as Grass Productivity , laid the foundation for what is now considered a precursor to modern rotational grazing systems, including Holistic Management and Adaptive Multi-Paddock grazing.