03087naa a2200313 a 450000100080000000500110000800800410001902400380006010000240009824501270012226000090024952021760025865000130243465300120244765300180245965300240247765300150250170000220251670000250253870000200256370000220258370000180260570000220262370000190264570000180266470000210268270000180270377300520272121102792023-01-24       2019    bl uuuu     u00u1 u    #d7 a10.1016/j.livsci.2018.11.0172DOI1 aRODRIGUES, J. P. P.  aTechnical notebEvaluation of an automatic system for monitoring rumination time in weaning calves.h[electronic resource]  c2019  aRumination time is a relevant marker for health evaluation. The use of rumination monitoring systems can decrease labor costs when measuring rumination time. The objectives of this study were to: i) validate the Hr-Tag rumination monitoring system for estimating rumination time in Zebu calves during the weaning period and ii) to evaluate the Hr-Tag capacity to identify differences in daily rumination patterns during the weaning period. Thirty-two Gyr calves averaging 69 ± 7.6 kg body weight and 77.0 ± 4.0 days were used. Calves were fed 4.7 ± 0.5 L/day of whole milk and ad libitum commercial textured starter ration up to 83 days old (pre-weaning period). During the weaning period (84?86 days old) the same starter was used, but corn silage was also available and only half the milk dose was offered. After weaning (87?92 days old, post-weaning period) only corn silage and starter were used. For the Hr-Tag system validation, the rumination time obtained by Hr-Tag was compared with visual observations at four 2 h intervals (0600 to 0800, 0800 to 1000, 1400 to 1600, and 1600 to 1800 h) at pre- and post-weaning. Two observers were used in all visual evaluations. To compare daily rumination pattern at pre-weaning, weaning and post-weaning, only the Hr-Tag data was used. Rumination time values between observers were highly correlated (ρ = 0.956; P &lt 0.001). Visual and Hr-Tag rumination time did not follow a similar probability distribution (P &lt 0.001), but they were correlated (ρ = 0.702; P &lt 0.001). The Hr-Tag system overestimated rumination time, mainly when the calves had visual rumination activity close to or equal to zero. The Hr-Tag detected differences in rumination time between weaning periods (P &lt 0.05). In conclusion, the Hr-Tag system overestimates rumination time in weaning calves, mainly by recording nonexistent rumination. However, the Hr-Tag system recorded rumination values correlated to visual observations and detected differences in rumination activity among weaning periods.  aBehavior  aChewing  aHr-Tag system  aPrecision livestock  aValidation1 aPEREIRA, L. G. R.1 aDINIZ NETO, H. do C.1 aLOMBARDI, M. C.1 aLAGE, C. F. de A.1 aCOELHO, S. G.1 aSACRAMENTO, J. P.1 aMACHADO, F. S.1 aTOMICH, T. R.1 aMAURÍCIO, R. M.1 aCAMPOS, M. M.  tLivestock Sciencegv. 219, p. 86-90, jan. 2019.