April 23, 2018

Interpretive Summary: Characterization of Inappetent Sheep in a Feedlot using Radio-Tracking Technology

Interpretive Summary: Characterization of inappetent sheep in a feedlot using radio-tracking technology

By: Megan LaFollette

In March 2018, Journal of Animal Science published an article that investigated using radio frequency identification (RFID) technology to track inappetent sheep in a feedlot. Before sheep are shipped for live export, they are first held in a feedlot so that they can be monitored while they adjust to a new diet of pelleted feed. During this period in the feedlot and shipping, a major cause of mortality is from reducing feed intake or simply not eating feed (inappetence), which is associated with salmonella infection. If inappetent sheep could be identified earlier in the process, they could be given veterinary care or alternative feeding arrangements – thereby improving health and welfare. The purpose of this study was to use RFID technology to compare sheep feeding and drinking behaviors with sheep survival and body condition at a commercial feedlot.

In this study, 8,206 sheep were monitored for 6 to 31 days across four consignments from September 2011 to June 2012. Sheep were of a variety of breeds, sexes (primarily castrated males), ages (weaners to 2 yrs), and farms of origin (284 total farms). Sheep were assigned a body condition score at intake and exit. RFID ear tags recorded feeding and drinking frequency and duration, although only the first 6 days were compared between sheep for consistency. Dead sheep were examined by a veterinarian to determine cause of death.

Results showed that only 76 sheep died (<1%) in this study with about half of those dying from salmonella. Sheep that died from salmonella decreased the amount of time spent at the feed trough from days 1 to 6, which indicates they went off feed. Over half of these animals also spent less than 30 min per day at the feeder, with 45% spending less than 15 min per day at the feed trough. However, when comparing them to sheep alive at exit, on day 1 about 19% of sheep alive at exit also spent less than 15 min at the feed trough. Even by day 6 about 2% of sheep alive at exit still spent less than 15 min at the feed trough. Therefore, time at the feed trough alone – particularly before day 3 – is not an indicator of potential infection. Body condition score was higher in sheep that died, which indicates they may not have been in poorer condition initially. Drinking behavior did not differ between sheep alive or dead at exit.

Overall, this study shows that RFID tags can successfully be used to track sheep eating and drinking behavior. However, data gathered from RFID tags may not assist in identifying sheep inappetent animals at risk from salmonella because of large variation in these animals and many sheep being off feed early on in the feedlot. However, it may be possible to use time spent at the feed trough as a potential indicator of illness beginning on day 3 at the feedlot. Additionally, experienced stockmanship is needed to identify sheep that may require veterinary attention or alternative feeding arrangements to help improve sheep health and welfare.

To view the full article "Characterization of inappetent sheep in a feedlot using radio-tracking technology," visit the Journal of Animal Science