Sustainable weight of ear-borne devices for cattle.

Approaches to precision agriculture are increasingly being applied to enhance animal husbandry through data collection and trend analysis. A growing number of technologies involve ear-borne devices such as EID's (i.e., Electronic Identification tags), health indicators, and location trackers. However, limited research has been conducted to determine how much weight cows' ears can sustain for a prolonged period of time. Our objectives were to determine if tag weight affects the ear healing rate, mobility, or orientation. Three tag weights (62, 89, and 124 grams) were compared to an unweighted tag (14 grams), using a commercial, two-post ear-tag (i.e., an EnduroTag). These weights were observed daily on 17 dairy and 17 beef cows for six weeks to assess overall ear health (i.e., tissue inflammation), continued mobility of the ear (i.e., movement and twitching), and severity of ear droop. Overall, the results indicate there is a significant difference (P < 0.05) in acute irritation, droop, and mobility between the four weight treatments examined. Furthermore, the final observation evaluating the degree of healing after six weeks also showed a significant difference (P < 0.05) between tag weights. This information regarding the healing outcome, orientation, and mobility of the ear is valuable to the growing suite of ear-borne technologies.