Estimating intake by cows an important task of estimating forage intake needs

How much does a cow consume?
I often get asked how much hay needs to be fed to get cows through the winter. Quality of hay, hay wastage and size of cows all play into estimating forage intake needs.
Estimating intake by cows is an important part of the task of calculating winter supplement needs. Producers that wish to be cost efficient in the supplementation feeding this winter, will calculate and feed the most appropriate type and quantity of supplement. Hay or standing forage intake must be estimated in order to make the calculations.
Forage quality will be a determining factor in the amount of forage consumed. Higher quality forages contain larger concentrations of important nutrients so animals consuming these forages should be more likely to meet their nutrient needs from the forages.
Also, animals can consume a larger quantity of higher quality forages.
Higher quality forages are fermented more rapidly in the rumen leaving a void that the animal can fill with additional forage. Consequently, forage intake increases.
For example, low quality forages (below about 6 percent crude protein) will be consumed at about 1.5 percent of body weight (on a dry matter basis) per day. Higher quality grass hays (above 8 percent crude protein) may be consumed at about 2 percent of body weight.
Excellent forages, such as good alfalfa, silages or green pasture may be consumed at the rate of 2.5 percent dry matter of body weight per day.
The combination of increased nutrient content and increased forage intake makes high-quality forage very valuable to the animal and the producer. With these intake estimates, now producers can calculate the differences needed to be met with supplement.
Michigan State University animal scientists studied four hay feeder design types: ring, cone, trailer or cradle.
The round bale “ring feeder” was seven and a half feet in diameter with 18 feeder spaces separated with bars at a 70-degree angle 14 inches apart. The top rail was at four feet of height. Solid material made up the first two feet of height.
The “cone feeder” was the same diameter and had the same feeder space bars as the ring feeder. Bottom and top sections were solid, with open feed access in the middle two feet of height. Overall height was six feet. An interior cone of bars kept the bale in the center of the feeder.
The “trailer feeder” was 20 feet long by seven feet wide, but hay was placed in only 12 feet of length. It had bars set at 50 degrees every 16 inches. Within the space used, it contained 19 feeding spaces.
The “cradle feeder” was 12 feet long by six feet wide. Vertical bars were spaced about eight inches on all sides of the cradle, thus cows could not put their heads inside the feeder.
All feeder types allowed approximately 14.5 inches for each animal. Dry matter hay waste was 6.1 percent, 3.5 percent, 11.4 percent and 14.6 percent for the ring, cone, trailer and cradle feeders, respectively.
The hay wastage for all types was comparatively low in this study, perhaps because of the high quality of the hay used. Producers that feed lower quality grass hays may expect even greater percentage feeding wastage.
There were differences in the behavior of cows at the feeders that may be involved with the differences in wastage. Cows eating from the cradle feeder had about three times as much butting and displacement behavior as other feeder types and four times as many entrances compared to cows feeding at the other type of feeders.
The researchers determined that slanted bar designs encourage animals to keep their head in the feeder for longer periods while eating. If a rancher routinely feeds a ton of hay per cow per year, and the hay is valued at $80 per ton, then he would save $8.80 per cow per year (in hay costs) by using a feeder that reduces hay loss by 11 percent.
If you have questions concerning this topic or related topics, please contact the OSU Extension Center at 273-7683.