Modelo de simulação do desempenho reprodutivo de vacas de corte baseado no escore de condição corporal

Abstract

Mathematical models are a useful commercial and research tool to aid in the decision-making process and to improve understanding of the system being studied. In livestock production system, where the outputs are dependent on variables of diverse nature, the use of modeling is an additional tool to professionals in this area. The objectives of this work were: 1) evaluate the use of mathematical models in the beef cattle industry, by reviewing the literature; 2) develop a dynamic mathematical model to describe the reproductive process in production systems and to simulate reproductive performance based on the body condition score (ECC) at calving and sexual maturity; 3) Perform an internal evaluation of the model. This is an empirical and dynamic model that has both deterministic and stochastic elements. It was developed and implemented in the RURAL FAZPEC software. For lactating cows, the model was based on the relationship between the interval between birth and conception (IPC) and the body condition score at parturition; for heifers the conception rate was considered based on age and/or weight at puberty. The model generates as outputs reports that include total kg of weaned calves per year, among other measures. The use of the model in decision-making activities is dependent on the ensuing validation step; for educational purposes the model allows visualization of dynamic aspects of production systems and the impact that results from changes in management practices. The model is efficient in simulating the reproductive performance of beef cows and it allows better understanding of the production system. An adjustment in the conception rate, as an output, is necessary. The concepts applied in the construction of this model may contribute in the development of other models in future modeling studies for beef cattle production systems. It is also imperative to stimulate the formation of comprehensive databases in the current production environments, to allow full benefits to be reaped from modeling tools.