Tesis
Alternativas de manejo para pastagem natural na serra do sudeste
Fecha
2016-02-22Registro en:
DUTRA, Gabriela Machado. Alternative management for natural pastures in serra do sudeste . 2016. 69 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Santa Maria, Santa Maria, 2016.
Autor
Dutra, Gabriela Machado
Institución
Resumen
The work was carried out to evaluate characteristics of natural grassland and body
development of rearing beef heifers, submitted to different types of grazing management in
the spring / summer period. The experiment was conducted in natural pasture belonging to
EMBRAPA Pecuária Sul, in the municipality of Bagé, Rio Grande do Sul, from October 2014
to March 2015. The treatments were continuous and rotational grazing methods, both
managed on variable stocking rate based on forage mass above 8 cm. The experimental
animals were Brangus heifers from EMBRAPA Pecuária Sul cattle herd, with initial weight of
267 kg and 18 months old. The stocking rate was increasing during the trial period. The
available forage on offer was similar between treatments and between the two periods. There
was no interaction treatment x period for average daily gain (ADG), gain per area (GPA) and
body condition score (BCS) and these variables were similar between treatments (P> 0.05).
At the end of the experiment average heifers reproductive tract score (RTS) was 3.68. The
descriptor variables of sward structure showed no significant difference between grazing
methods (P>0.05), except for the percentage of stems (P=0.003) that was higher in the
continuous treatment (16.06%). Species of greater participation and relative coverage in the
area were evaluated Paspalum notatum, Paspalum pumilum, Axonopus affinis, Mnesithea
selloana, and the exotic Eragrostis plana species. The descriptor variables of interest and
importance of the species did not differ between grazing methods (P>0.05) or interaction
treatment x station. For average canopy height there was no difference between treatments
(P= 0.798) nor interaction treatment x station (P=0.621). The importance value index (IVI)
showed no difference between treatments (P=0.798), or interaction treatment x station
(P=0.901). Management of a natural pasture, both under continuous as rotational grazing,
during the spring-summer period, enables proper body development for mating beef heifers at
24 months. The grazing method did not change the structure and dynamics of vegetation in
the study period. Continuous grazing reduced the floristic diversity comparing to rotational
grazing, with clear dominance of Eragrostis plana species.