RESUMO
The Insentec Roughage Intake Control (RIC) system has been validated for the collection of water intake; however, this system has not been validated for water restriction. The objective of this validation was to evaluate the agreement between direct observations and automated intakes collected by the RIC system under both ad libitum and restricted water conditions. A total of 239 crossbred steers were used in a 3-d validation trial, which assessed intake values generated by the RIC electronic intake monitoring system for both ad libitum water intake ( = 122; BASE) and restricted water intake ( = 117; RES). Direct human observations were collected on 4 Insentec water bins for three 24-h periods and three 12-h periods for BASE and RES, respectively. An intake event was noted by the observer when the electronic identification of the animal was read by the transponder and the gate lowered, and starting and ending bin weights were recorded for each intake event. Data from direct observations across each validation period were compared to automated observations generated from the RIC system. Missing beginning or ending weight values for visual observations occasionally occurred due to the observer being unable to capture the value before the monitor changed when bin activity was high. To estimate the impact of these missing values, analyses denoted as OBS were completed with the incomplete record coded as missing data. These analyses were contrasted with analyses where observations with a single missing beginning or end weight (but not both) were assumed to be identical to that which was recorded by the Insentec system (OBS). Difference in mean total intake across BASE steers was 0.60 ± 2.06 kg OBS (0.54 ± 1.99 kg OBS) greater for system observations than visual observations. The comparison of mean total intake across the 3 RES validation days was 0.53 ± 2.30 kg OBS (0.13 ± 1.83 kg OBS) greater for system observations than direct observations. Day was not a significant source of error in this study ( > 0.05). These results indicate that the system was capable of limiting water of individual animals with reasonable accuracy, although errors are slightly higher during water restriction than during ad libitum access. The Insentec system is a suitable resource for monitoring individual water intake of growing, group-housed steers under ad libitum and restricted water conditions.
