Mercedes Gonzalez & Nuria Garcia
Pasture-based milk production systems are seasonal, requiring cows to become pregnant every 365 days to take advantage of fresh grass as an economic feed source. Grazing cows are more vulnerable to negative energy balance than cows in intensive systems since they are more likely to suffer nutritional imbalances, resulting in worse reproductive performance and lower farm profitability.
To strengthen economic sustainability, peaks of maximum grass growth during spring must be aligned with the highest animal requirements. The short time period (about 85 days) during which cows in seasonal grazing systems must conceive to maintain reproductive efficiency, leaves little room for delays, and therefore postpartum pathologies should be minimized.