Tandem bins – we’re mis-using their potential

At the two Passion for Pigs seminar locations in Iowa in December, Bob Baarsch from Herdstar.com did a presentation on the impact of out-of-feed events on herd health and performance. Since some of the last research I did while at the University of Nebraska involved out-of-feed events, I followed his presentation with interest.

Using the large farm based data set of hourly feed bin weights available with their BinTrac product, Bob demonstrated many of the common causes of out-of-feed events in wean-finish facilities. Probably the most interesting discussion was the role of tandem bins in contributing to the problem.

For many years, producers have been installing tandem bins on feed lines. The idea is that with 2 bins per feed line, there should always be an inventory of feed available for distribution to feeders within the barn. In theory the outlet slide on a single bin is opened and feed dispensed from that bin. When the bin becomes empty, the slide is closed and the slide on the other bin is opened. At the same time, feed is ordered for placement in the now empty bin.

Many production systems install 12-18 ton bins for this tandem series. The goal is the empty bin will always take a consistent amount of feed, making scheduling of loads from the mill easier.

As Bob demonstrated with farm data, tandem bins often lead to more out-of-feed events and feed delivery problems. I’ve seen many of the problems he identified on farm visits.

A common problem with tandem bins is related to when to change bin slides to the feed delivery auger. The problem is magnified when sites/rooms are only visited once per day for animal care. In this case, as the pig care provider departs a site, they ‘bang’ on the boot of the bin and determine that feed is present for delivery to the pigs the remainder of the day. In many cases, the amount of feed remaining in the bin is only enough for 2-4 hours of deliveries. No feed gets delivered following this bin becoming empty until the next day when the slide to the bin full of feed is opened, etc.

A second problem Bob identified is partial slide openings. If both bins have their slides ‘cracked’ so feed can flow from both bins, in almost 100% of the cases the feed flows from the bin at the end of the auger, not the inner bin. In this case, the outermost bin empties while the inner bin has a slow decline in feed inventory. Feed is always delivered to the outmost bin. If there is an product in the inner bin that requires a withdrawal prior to slaughter it doesn’t happen. Bob showed data from farms where it took more than 60 days for the inner bin to empty.

Another routine problem is refilling the bin(s) at a point prior to their being totally empty. At this point you put fresh feed on top of feed that may have been in the bin 2-3 weeks. The fresh feed flows out first and older feed becomes compacted and even more difficult to remove. You now have a 12-18 ton bin that may stop flowing after only 6 ton of feed removal due to bridging and caking of the older diet(s) in the bin. In addition to feeding difficulties you now have a feed delivery problem as the bin doesn’t hold the normal delivery problem, leading to small batch deliveries and higher delivery charges.

The take home message from Bob – tandem bins take a lot of management to effectively use their potential. If you have tandem bins the best thing to do is visit the site at least 2x daily to be sure feed is available to be delivered to the barn and to manage the bin slides in an appropriate manner. If you don’t you will almost always have out-of-feed events of some type and feed flow problems from one or both bins.

Leave a Reply

Your email address will not be published. Required fields are marked *