Suplemento proteico e monensina para bovinos em pastejo no período das águas
Data
2021-02-24
Autores
Coutinho, Marina Pereira Souza
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Universidade Federal de Mato Grosso
Resumo
Two experiments with crossbred heifers (Nellore breed
predominance) under grazing during the rainy season were carried out with the
objective of evaluate the effect of monensin inclusion on protein and mineral
supplements on productive performance, pasture consumption, dry matter
intake and nutrient digestibility, as well as to identify changes in the ingestive
behavior of heifers, thermal comfort and its relationship with ingestive behavior
through the Index of thermal stress for cows (ITSC) in grazing. The
experimental area consisted of 7 hectares of Brachiaria brizantha cv. Marandu
under continuous stocking, located in Rondonópolis-MT. In both experiments, a
2x2 factorial scheme and a completely randomized design were adopted. The
first experiment was carried out from December 2015 to March 2016. The
treatments consisted of two protein supplements (high and low consumption)
and the inclusion or not of monensin. Productive performance, nutrient
consumption and digestibility were evaluated. Forty heifers with an average
initial weight of 213.8 ± 4.5 kg were used. There was no difference (P>0.05) in
the animals' performance among treatments, with an average daily gain of
0.588 kg animalday
-1
. There was no interaction (P<0.05) between sodium
monensin and supplements for consumption and digestibility variables, except
for crude protein (CP) digestibility. There was equality in the dry matter (DM)
intake among treatments (± 2% of the animals' body weight). However, there
was a reduction (P<0.05) in pasture intake with the high consumption
supplement, showing a substitutive effect. There was no treatments effect on
the digestibility parameters (P> 0.05), but a greater CP digestibility (P<0.05)
was observed when monensin was associated with low-consumption protein. It
was concluded that monensin does not improve the performance of grazing
heifers by consuming high and low consumption protein supplements, and its
use is dispensable. The second experiment was carried out from December
2016 to March 2017. The treatments consisted of two supplements (mineral and
protein) and the inclusion or not of monensin. Forty heifers with an average age
and initial weight of 9 months and 159.2 ± 1.3 kg, respectively, were used.
There was no interaction (P> 0.05) between the supplement type and monensin
and there was no influence (P> 0.05) of the supplement type on the animals'
performance. However, monensin promoted greater (P <0.05) weight gain of
the animals (± 107 ganimal.day-1
). There was an interaction (P <0.05) between
supplementation and monensina inclusion on behavioral activities, except for
idle time. There was equality in the average grazing time (455 minutes) of
animals that received mineral supplement, regardless of the monensin
inclusion. The monensin inclusion in the protein supplement reduced (P <0.05)
the grazing time by 45 minutes. The ITSC value influenced (P <0.05) the
ingestive behavior and the increase of this index reduced the grazing time in all
treatments. Monensin improves the weight gain of animals grazing tropical
forages under continuous stocking management.
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COUTINHO, Marina Pereira Souza. Suplemento proteico e monensina para bovinos em pastejo no período das águas. 2021. 64 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Mato Grosso, Campus Universitário de Rondonópolis, Instituto de Ciências Agrárias e Tecnológicas, Rondonópolis, 2021.