Validação do nanolipe como indicador para estimativa do consumo em bovinos leiteiros

Abstract

Five crossbred heifers were used in order to validate the NANOLIPE as a marker to estimate dry matter intake in dairy cattle. The results obtained with this marker were compared with three other methods: total collection, fecal crude protein and Klason Lignin (in combination with NANOLIPE). There was no difference between the methods tested (P> 5%), a fact that validates the NANOLIPE as an efficient marker in estimating dry matter intake. The best way and time of fecal sampling in studies with NANOLIPE were also determined. The combination of Klason Lignin (internal marker) with NANOLIPE (external marker) proved to be a simple and efficient alternative to determine dry matter intake in dairy cattle. In order to statistically evaluate the linearity of the method of infrared spectrometry with Fourier transform to quantify the marker NANOLIPE in feces of dairy cattle, an analytical curve in matrix was created. Four levels of concentration were defined to evaluate the linear range of work: 0.05, 0.10, 0.15, 0.20 milligrams of NANOLIPE per gram of feces. The height of the absorbance peak at wavenumber 1035.62 cm-1 provided the most appropriated relationship to determine NANOLIPE. Three tests were applied to ensure normality, independence and homoscedasticity of the residuum, respectively: Ryan-Joiner, Durbin-Watson and Brown-Forsythe. Analysis of variance showed that the deviations of the linearity were no significant. The value of the correlation coefficient of 0.9998, supported by the statistical analysis presented is excellent.