Use of stochastic models to simulate long-term dynamics of mountain cattle herds under low-labour availability scenarios

Mathematical models are useful tools to evaluate innovations or new management strategies in livestock farming systems because they allow advanced simulation of the consequences of their implementation, taking into account the existing relations between different components of the farm production system. In recent years, cattle farming systems in the Spanish Central Pyrenees have evolved towards extensification and lower dependence on inputs, linked to a reduction in the availability of labour dedicated to farming activities. A stochastic dynamic model (Nodriza) was designed to simulate long-term herd dynamics, taking into account the effects of nutrition and management applied at a batch level to animal reproduction performance and herd dynamics. Long-term effects of complex scenarios of nutrition and management on mountain cattle farming systems can be simulated and evaluated in terms of technical and economic performance, as well as the risk involved (derived from stochastic simulation of animals, variability within the herd and between years). The traditional management strategy observed in the study area was compared to an alternative low-labour management system. Their impacts on fertility, calf production and economic performance were analyzed. Preliminary results showed that, under certain circumstances, the low-labour scenario could be as good as the traditional one in terms of technical and economical performance, and also implied lower levels of risk under uncertain climate conditions.