Avaliação de protocolos para estimativa do consumo voluntário por caprinos em pasto nativo

Abstract

Considering all the knowledge about the variation of native grasses quality and quantity is dependent on the time of year, plus the unknowing and inability in determine the dry matter intake of goats, it sought with this research estimate the pasture intake by these animals. The experiment was conducted to evaluate the external markers chromium oxide (Cr2O3), titanium dioxide (TiO2) and insoluble lignin purified and enriched (LIPE®), such as internal markers: indigestible dry matter (MSi), neutral detergent fiber indigestible (NDFi) and acid detergent fiber indigestible (ADFi) to estimate the dry matter apparent digestibility, fecal dry matter production and estimated dry matter intake by goats kept on native pasture in the semiarid region. It worked with 20 castred males without defined breed, with average body weight of 26 ± 8.4 kg, when five of all were rumen fistulated and 15 did not. The field activity lasted 30 days, 15 days to adapt the animals and the other 15 to providing indicators and colect samples (feces and extrusa). The statistic experimental design was completely randomized (CRD), and the results submitted to the Tukey test at 5% for comparison of means. The internal markers were submitted to descriptive analysis with in vitro digestibility of dry matter (DM) through regression analysis. And then, the results presented that estimates of dry matter intake considering IVDMD, through internal markers were more precise and accurate when used MSi and NDFi, and the opposite being observed for ADFi and the equation. Although about the internal markers, IVDMD and equations were used to estimate the dry matter intake, but significant differences (P<0.05) were observed for the equations while the estimates fecal output through external markers differed significantly (P>0.05) from the result of the total collection. TiO2, Cr2O3 and LIPE ® markers presented statistically different estimate (P>0.05) from total collection, as well as the TiO2 from others markers. LIPE® and Cr2O3 underestimated the fecal output. Regarding the time and method of collection no statistical differences (P>0.05), for any marker and/or method. Therefore, even on native grazing, internal markers proved to be a relevant tool in obtaining data on digestibility and dry matter intake. Can thus supply management supplementation for goats when grazing in rangeland.