Efecto de diferentes estrategias de alimentación sobre las variables biofísicas, en dos sistemas lecheros de base pastoril, con cargas animales contrastantes, durante el verano

Dairy farming is the sector with the highest income per hectare (ha). Although annual production in millions of liters has not changed significantly over the last decade, the country's dairy herd has declined, with a loss of farms and total farmed area, and a consequent increase in the stocking rate of the systems. The objective of this study was to compare a high-productivity (HP) system with an average stocking rate in the grazing platform (GP) area of 2.7 milking cows per GP (MC/ha GP), aimed at achieving high milk productivity per ha, supplemented with concentrate, and with reserves produced outside the GP area. Another low-cost (LC) system with an average animal load of 1.6 MC/ha GP, with operational simplicity as a premise, self-sustaining from the fiber point of view with the entire reserve produced in the GP area, where the animals were supplemented with concentrate and with reserves (produced in the GP area). Both systems were managed with the same forage model, a 6-year perennial rotation without summer greening (SG). Grazing criteria were based on forage stock control and weekly growth rate (GR). The work was carried out at the Dairy Unit of the Southern Regional Center (CRS), in the department of Canelones (Uruguay), between December 21, 2021, and March 21, 2022. The systems did not show significant differences in forage intake by direct harvest (with differences in grazing opportunities), reserves, and concentrate per hectare. The systems differed in forage production, but these differences did not translate into forage intake per LC. The systems did not differ in milk production per milking cow (MC), but they did differ in milk and solids production per ha GP. Feed margins per MC were higher in the LC system, while better margins per surface area were achieved with the HP system.