Pulso de oxigênio: predição da produção de calor em bovinos e relações com consumo alimentar residual

Content Provider	Semantic Scholar
Author	Chaves, S. A. Feltrin, G. B. Nascimento, Maysa L. Lanna, Dante Pazzanese Duarte
Copyright Year	2014
Abstract	The interest on the use of feed efficiency indexes in beef cattle selection is increasing, by reduction on production costs and on en-vironmental impact, what is an important issue, since currently the focus is on the natural resources sustainability. Residual feed intake (RFI) obtained by the difference between observed and predicted dry matter intake, has been studied as a feed efficiency index that besides avoiding increase on body weight of the selected animals, for being adjusted for metabolic body weight, allows the identification of the individuals with lower dry matter intake with the same body weight and average daily gain. Performance cha-racteristics and their correlations with feed efficiency are well reported by the literature, however the biological basis for RFI variation are partially unknown. It is estimated that 9 % of the difference on RFI are explained by heat increment, 14 % for differences in digestion; 5 % for differen-ces in body composition; and 5 % for differences in activity. Then, 67 % of the RFI variance remains unknown and may be related to the energy required for biological processes such as pumping of protons into the mitochondria, protein turnover and ion pumping. Therefore, the energy use through biological processes seems to have a potential to contribute substantially on individual variation of feed efficiency. Although the heat production of an animal can be accurately measured by calorimetric chamber or using doubly labeled water, these methods, besides being practiced in artificial conditions are extremely expensive and require considerable experience and infras-tructure, which may become impractical selecting animals with lower requirement of maintenance. In this context, many researchers have been studying the possibility of predicting heat production from heart rate, since most of the O2 used by warm-blooded animals are transported to the tissues by heart pumping, an organ whose activity is about 10 % of the total heat production. The use of heart rate without calibration for the O2 volume consumed per heart beat can provide low accuracy estimates, however, the heat production estimated by that calibration in humans and animals is highly correlated with the direct measurement in calorimetry chamber. Hence, the aim of this review is presenting the methodology of estimation of heat production from heart rate calibrated to oxy-gen consumption and its relationship with RFI in beef cattle.
Starting Page	133
Ending Page	145
Page Count	13
File Format	PDF HTM / HTML
DOI	10.21071/az.v63i241.595
Volume Number	63
Alternate Webpage(s)	https://www.uco.es/ucopress/az/index.php/az/article/download/595/569
Alternate Webpage(s)	https://doi.org/10.21071/az.v63i241.595
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article