Performance and grazing behavior of Gyr dairy heifers in integrated production systems in the Cerrado biome

The study aimed to assess the performance of Gyr dairy heifers in four pasture systems: renovated pasture (RP), non-renovated pasture (NRP), crop-livestock integration (CLI) and crop-livestock-forest integration (CLFI). For our study, we used a Marandu Palissadegrass pasture with a slight to moderate stage of degradation. The experimental area had 7.5 hectares which were divided into 3 blocks with four grazing systems: RP, NRP, CLI and CLFI. Thirty-four Gyr dairy heifers with an initial body weight (BW) of 206.9 kg were used. There was no difference in total forage production between the grazing systems. The RP system had a higher % of leaves, while the NRP showed a lower % of leaves and a higher % of dead material. The CLFI showed the highest % of crude protein (CP) in the forage, and lowest levels in the NRP. There was no difference between the grazing systems in the % of neutral detergent fiber (NDF) and acid detergent fiber (ADF). When the BW factor was analyzed in isolation, it was observed that the NRP had a higher BW and there was a linear increase in BW as the grazing cycles progressed. There was an interaction between grazing systems and evaluation periods for the variables related to grazing behavior, with emphasis on the heifers in the NRP system, which ruminated for longer and grazed for less time during the evaluation period. The RP, CLI, and CLFI systems, when established, promoted a pasture of better morphological and nutritional quality for rearing Gyr dairy heifers.