Manejo do pastejo da BRS Ipyporã e BRS Paiaguás para produção de leite sob lotação rotacionada

Abstract

The increase in animal productivity on pasture is the object of a search for production systems. Thus, productive tropical grasses with high nutritional value are fundamental for the efficiency of pasture production systems. The objective was to evaluate the characteristics of the pasture, the performance of Girolando cows and the consumption of dry matter under cultivars of Urochloa spp. in rotated grazing. CHAPTER II: the productive performance and the canopy structure of two new cultivars of Urochloa spp. in rotational grazing system. The experimental design was entirely random, in an arrangement of a sub-subdivided plot (cultivar is the plot, year sub-plot and season the sub-sub-plot). Two genotypes (U. Hybrid BRS Ipyporã and U. brizantha BRS Paiaguás) were evaluated during two experimental years (2017/2018 and 2018/2019) and two seasons: summer and autumn, with 20 repetitions during summer and 12 in autumn. BRS Paiaguás showed higher forage mass (FM), forage accumulation (FA) and forage accumulation rate (FAR) when compared to Ipyporã cultivar (1.48, 1.55 and 1.42 times higher, respectively). The highest percentage of leaf and leaf / stem ratio (l/S) were observed in the cultivar Ipyporã. The leaf accumulation rate did not differ between cultivars (103.24 and 113.15 kg / ha / day of DM, for Ipyporã and Paiaguás, respectively). CHAPTER III: Milk production and dry matter consumption of Girolando cows and the structural characteristics of BRS Ipyporã and BRS Paiaguás cultivars were evaluated in rotational grazing. The cultivar BRS Paiaguás showed higher FM, FA, FAR and tiller population density (TPD) (1.32, 1.46, 1.48 and 1.66 times higher, respectively). The highest L/S ratio and highest volumetric density were observed at BRS Ipyporã (33.76 and 15.14% higher, respectively). The consumption of dry matter (CDM) differed only in the first evaluation, where it was higher for cultivating BRS Ipyporã (11.11 kg / cow / day) when compared to Paiaguás (10.02 kg / cow / day). The production and composition of milk did not differ between cultivars. The stocking rate was higher in BRS Paiaguás when compared to BRS Ipyporã (7.71 x 6.90 AU / ha-1, respectively). The cultivars studied showed potential for milk production, when adopting the management recommended in the present study, with an entrance height of 40 cm for BRS Ipyporã and 57 cm for BRS Paiaguás, with a 50% decrease.