Dairy Focus: Right feed bunk design can reduce shrinkage

Lowering feed shrinkage is an economic opportunity for nearly all dairies of any size. Shrinkage comes in many forms, and many factors result in feed waste.

Feed efficiency may be called milk production efficiency or dairy efficiency, but all these refer to the same thing: how efficiently a dairy cow converts feed to milk. Far more important than the name is how this efficiency can affect a dairy’s bottom line.

It all starts with bunk design. Feed is meant to be consumed by animals. For example, a properly designed feed bunk for heifers should, first and foremost, minimize feed losses behind the feed bunk. University research data has demonstrated that up to 20 percent of feed can be lost aft of (behind) the feed bunk.

Purchasing new feeders may not always be a practical way of controlling costs and keeping depreciation expenses low. However, the cost of hay waste alone can be substantial, especially when the hay price is relatively high. The value of reducing hay waste from 30 to 10 percent for a 20-cow feeder for 200 days, with hay valued at $100 per ton, was estimated at $1,942 annually per feeder in a Michigan State University beef cattle study.

Dry hay waste ranged from 3.5 to 14.6 percent for the various feeders. Cows feeding from a cradle feeder had nearly three times the agonistic interactions (head butting and displacement of other cows) and four times the frequency of feeder entrances compared with cows feeding from other feeder types. Feed losses were higher with agonistic interactions and feeder entrances.

This beef cow and forage-only study also revealed that design features are important in reducing the amount of hay waste associated with feeding in round-bale feeders.

In general, feed losses for dairy heifers will be lower when fed in equipment designs that require the animals to place their head through and reach down for feed as opposed to simply reaching horizontally for feed. Feed wagons, where the feed is at the same horizontal plane as the animal’s muzzle, have been demonstrated to increase feed losses.

Fence line feed bunks should be fitted properly for each size group of heifers. According to university research, post and rails, throat guards and/or self-locks should be checked and adjusted to proper dimensions.

While feed losses during feed delivery can be the most significant for many feeds on the farm, they have not been well-documented, with few studies having been done anywhere in the world. In fact, even the methods used to quantify feed wastage rates associated with different feed-out methods have not been well-described.

To address this situation, Dairy Australia’s Grains2Milk program conducted a study of feed wastage rates on 50 commercial dairy farms that used different feed-out methods. Farms involved in the study spanned the six different feed-out methods used on Australian dairy farms.

The study found that hay feeder design affects the amount of hay wastage. The researchers suggested strategies to minimize waste during feed-out, including using feeders that encourage cows to keep their heads in the feeder opening and reach for feed (for example, a slatted bar design on a ring feeder that forces cows to rotate their heads when entering or leaving the feeder), rather than allowing them to back away easily and drop hay on the ground.

The researchers recommend that if using bunks:

· Ensure adequate space for the number of cows (2.5 feet per cow).

· Aim for a height that allows cows to eat with their head in a natural grazing position (about 4 to 6 inches above the ground) to promote more saliva production.

· Ensure surfaces are smooth to avoid a buildup of waste feed, mold and odors. Plus, smooth surfaces are easy to clean.

· Consider concrete aprons around troughs to prevent mud and slush from contaminating feed and reducing palatability.

Reducing waste through more precise feed delivery can reduce feed costs and add revenue to the dairy enterprise.