Performance and behaviour of Nellore steers on integrated systems

Abstract

This study aimed to evaluate performance and behaviour of Nellore steers (Bos taurus indicus) in integrated systems. Treatments consisted of three different systems: livestock; crop-livestock; and livestock-forestry, with triple rows of eucalyptus trees. The experiment was carried out in Sinop, MT, Brazil, in a randomised complete block design with four replicates, during two seasons (dry-rainy transition and rainy). The experimental period was from 19 September 2015 to 10 January 2016. Nellore steers used in the experiment had an average initial weight of 344 kg ± 11 kg, in continuous stocking and variable stocking rate. Forage mass accumulation rate was evaluated and, independently of the system, had the highest values recorded during the rainy season. Microclimate was evaluated through temperature and humidity index, black globe temperature and humidity index and radiant heat load. Highest values were obtained from 11:00 a.m. to 3:00 p.m. at the dry-rainy transition period for all systems. Animal behaviour was assessed every 10 min from 7:00 a.m. to 5:00 p.m., and averages were calculated for every 2 h. The longest grazing period was recorded from 9:00 a.m. to 1:00 p.m., and then after 3:00 p.m., regardless of the system. Rumination occurred more frequently from 1:00 p.m. to 3:00 p.m. during the rainy season, and also in the shade for the livestock-forestry system. Highest weight gains per area were recorded during the rainy season and for the crop-livestock system. It is concluded that the highest yields can be achieved with the inclusion of the crop component in livestock production systems, and that Nellore steers in silvopastoral systems prefer to ruminate and stay idle in the shade.