Validation of a portable, self-contained individual feeding unit for monitoring supplement intake of grazing cattle

Abstract

This experiment aimed to validate feed intake and bunk attendance data collected from a portable, self-contained feeding unit (SmartFeed; C-Lock Inc.) by comparing estimates collected electronically (electronic observations, EO) with direct observations and video recordings (DO). To validate individual animal intake, 30 cows were allowed access to 3 portable units (2 feeding bins per unit) for 6 h. Feed in each bin was removed and weighed in an external scale at the end of each cow visit. To validate total feed disappearance, 75 cows were assigned to 1 of 3 pastures equipped with a portable unit. Feed disappearance over 24 h was assessed manually over 21 consecutive days using an external scale. Ten cows per pasture were randomly selected and identified to facilitate collection of video observational data. Two trained observers recorded animal identification and start and end times for a visit (n = 480 min/d; 3 d). When regressing the EO and DO results within individual cow visit, a linear fit was detected ( P < 0.01; r 2 = 0.95). Methods were very strongly correlated (r = 0.91) when all visits were analyzed but decreased to strong (r = 0.78) when DO intake was ≤0.1 kg. When regressing the EO and DO results for total feed disappearance, a linear fit was detected ( P < 0.01; r 2 = 0.97): as DO total feed disappearance increased, the EO output linearly increased. For observational data, Cohen’s kappa coefficient for agreement between DO and EO was considered strong (0.96). The sensitivity of EO in yielding true positive results was 97%, whereas specificity in yielding true negative results was 99%. These results indicate the portable, self-contained feeding units used herein are sufficiently effective for detecting cow presence at a bunk and measurement of feed consumption.