Classification of compost barns system of milk producers from cooperatives in the mission region / Classificação do sistema de celeiros compostos de produtores de leite de cooperativas na região de missão

Abstract

This work classifies the dairy farms that use compost barns (CB) as a feedlot system for dairy cows in the Brazilian subtropical region, in terms of farm structure, constructive aspects, environmental and compost bedded pack characteristics, and reports the variability among the dairy farms that adopted it. Additionally, this research identifies structural and management factors that interfere in the compost bedded pack quality. The data were obtained in loco, with facilities measurements, herd observations and collection of technical information, in 30 dairy farms. The clustering analysis, based on 12 variables, resulted in the formation of three groups: conventional and adapted CB (n=18, with new and adapted facilities, of different sizes, full time using, with adequate pack characteristics or not), large conventional CB (n = 6, larger barns, more similar to American models, full time using) and, partial use CB (n = 6, used in hot hours of the day or rainy season, with better pack characteristics among groups, although do not have mechanical ventilation and the pack is revolved only once a day). In addition to the consolidated variables related to the pack management and quality (DM, OM, pH, W, C:N ratio, temperature and density), it is reported that the stirring frequency, resting space area per animal, presence of mechanical ventilation on the barn, type of material used to compose the bedded pack and local relative humidity are factors that influence the main variables of the pack and can be key points for the success of the CB system in subtropical regions of Brazil.