Think Feet at the Feedbunk – Pat Hoffman, Vita Plus
So we fire up the tractor, load the TMR mixer, turn into the central feed alley of the heifer freestall barn, and start discharging feed. Typically, the last thing we want is the heifers to run out of feed, so we make sure they have plenty.
Oops. We forgot to add a couple of details to the story.
We are feeding heifers in an overcrowded six-row freestall barn, which means we have to put even more feed in the bunk to make sure all the heifers will have enough feed for the day.
The above scenario is pretty common. Managing dairy heifers in six-row freestall barns or other similar heifer facilities is often labor efficient. But, with every advantage to a dairy heifer housing facility, we often find disadvantages. When dairy heifers are housed in freestall barns or other facilities with limited bunk space, the most common bottleneck is feedbunk management and, if not monitored properly, it can cause some chronic growth and health problems in our dairy heifers.
The great wall
One of the primary building concerns we often observe when dairy heifer facilities are built is if the feed curb is high enough to retain great amounts of feed in the feed alley to mitigate feed falling into the manure alley. It makes sense, but what is often forgotten is whether the heifers can actually reach the feed. For example, feedbunk throat height guidelines published by agricultural engineers for three- to six-month-old dairy heifers are actually not very high. Recommendations range from 10 to 14 inches.
And here’s the rub. Throat height is not the same as feed curb height. Throat height is measured from the base of the manure alley to the top of the feed curb. So, if the feed alley is 6 inches higher than the manure alley, the feed curb height should only be 4 to 8 inches for three- to six-month-old heifers. Also, these guidelines assume the feed curb is 4 inches wide. If the feed curb is wider, the feed curb should be reduced by 1 inch in height for every extra inch in width. For this reason, we often see a single 2-by-4-inch board on its edge, with a 3-inch pipe affixed to the top of it, serving as a feed curb for three- to six-month-old heifers.
A number of research studies have evaluated the effects of overcrowding heifers at the feedbunk. These studies have found some increased growth variance, but the overall effects on average daily gain in heifers have been minimal. In some ways, this research makes us overconfident that feedbunk design and management has a minimal effect on heifer development.
However, no long-term studies have evaluated heifer feedbunk design, overcrowding and/or reaching behavior on long-term foot and leg health of dairy heifers.
Unfortunately, when heifers have to aggressively compete at the feedbunk, or can’t easily reach the feed due to excessively high or wide feed curbs, we see several health problems emerge. These largely appear as foot problems, such as shallow heels, corkscrewed toes, stretched flexor tendons and foot abductions in heifers that have chronically reached for feed over long periods at a time.
What can we do?
We can push up feed more frequently so the heifers don’t have to reach so far. We can also have the hoof trimmer make more frequent assessments of heifer foot health. A more aggressive heifer culling strategy – perhaps aided by genomics – can be used to reduce overcrowding.
Or maybe we can re-do those big, high, wide feed curbs for our heifers that are less than eight to 10 months of age so reaching and foot issues don’t start so early in life. Take a little time to observe heifers eating feed and what their feet are doing in the process. How far can they reach feed and keep their feet nice and square on the floor? When you have a good picture of what they do to reach feed, do your best to keep the feed in the heifer bunk as close as they need it.
Starting Strong - Calf Care