TITLE:
Sward Structural Characteristics and Performance of Beef Heifers Reared under Rotational Grazing Management on Campos Grassland
AUTHORS:
Cezar Wancura Barbieri, Fernando Luiz F. de Quadros, Felipe Jochims, Émerson Mendes Soares, Leandro Bittencourt de Oliveira, Régis Maximiliano R. Carvalho, Gabriela Machado Dutra, Felipe Xavier de Lima, Franciele Gusatto
KEYWORDS:
Average Daily Gain; Duration of Leaf Expansion; Herbage Mass; Rotational Grazing; Stocking Rate
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.7,
March
26,
2014
ABSTRACT: This study aimed to evaluate the effect of two
rest intervals on structural sward characteristics and productive performance
of beef heifers reared on Campos grassland managed on rotational grazing. The
treatments were two intervals between grazing of 375 and 750 DD (degree days),
based on thermal cumulative sum for leaf expansion of native grasses belonging
to two functional groups. The experimental design was a randomized complete
block design with two treatments and three replications. The tested animals were beef heifers
with initial age of 12 months and average weight of 185.2 ± 17.4 kg. Measures
in the pasture were: herbage mass, mass of green leaf blades, stem mass, dead
material mass and green leaf allowance. The 750 DD rest interval presented
higher herbage mass (24%), higher green herbage mass and 19% more leaves in the
canopy. This rest interval also presents a high proportion of dead material and
stems in the sward structure. In the other way, the 375 DD rest interval
presents better chemical characteristics, with 20% more crude protein in the
hand plucking samples. Heifers’ dry matter intake was similar between the rest
intervals (2.04% of live weight) and the bite mass was also similar (0.22 g DM per bite) but the
animal performance was higher in the 375 DD rest interval. The stocking density
showed similarity between treatments with an average of 875 kg/LW/ha. The live
weight gain per area was higher in 40 kg/LW/ha
(P = 0.117)
for 375 DD rest interval, reaching 251 kg/LW/ha produced over
the 149 experimental days. Based on these results, we can conclude that the
treatment of shortest interval between defoliation gave the highest gain
individual animals in warm seasons.