Snaplage is generally understood to be the entire ear of corn (husk, cob, grain, and part of the shank). Snaplage is harvested by a silage harvester with a snapper head and a kernel processor. Earlage is similar to snaplage but it generally does not include the husk and has very little of the shank.
Earlage can be harvested using a snapper head or by adjusting the combine to break up the cob and return the cob and grain to the bin. The feeding characteristics can vary greatly depending on the amount of husk and shank in the final product. For the purpose of this article, the term snaplage will be used for this final product.
There are positives and negatives to feeding snaplage. Producers must carefully evaluate their feeding situations and decide if snaplage is a good fit for their operation.
Recently, researchers at the University of Wisconsin completed an 8-week feeding study in which they compared snaplage, high-moisture shelled corn (HMSC), and a mix of snaplage and dry corn fed to 60 cows, approximately 100 days in milk. Upon feedout, HMSC was 78.2 percent dry matter (DM) and 71.2 percent starch, and snaplage was 68.5 percent DM and 61.0 percent starch.
Forage content was the same in all diets. The three experimental diets were:
1) 21.5 percent HMSC and 9 percent soy hulls (24 percent dietary starch),
2) 29.2 percent snaplage (26 percent dietary starch), or
3) 20.0 percent snaplage and 9.2 percent dry ground shelled corn (27 percent dietary starch).
Dry matter intake was significantly higher in cows fed HMSC. Milk yield was not affected by diet, however milk fat percentage for cows fed HMSC was significantly higher than for cows fed snaplage and the snaplage + dry corn diets (3.67 percent, 3.40 percent, and 3.52 percent, respectively). This result may be attributed to the low moisture HMSC (21.8 percent) having less negative effect on ruminal pH in comparison to the snaplage (31.5 percent moisture). The 3.5 percent fat-corrected milk yield was not statistically different (88.9, 85.1, and 87.0 lb/cow/day, respectively).
In this study, feed costs were lowest for the snaplage diet and income over feed cost was greatest for the snaplage + dry corn diet. The authors concluded that the mixture of 2/3 snaplage and 1/3 dry ground shelled corn was the most favorable treatment.
Snaplage can lower feed costs because of lower fuel costs in hauling snaplage compared to corn silage. For grain harvest, snaplage offers higher yields and less harvesting costs compared to combining and running corn grain through a grinder or roller mill. While snaplage may offer feed cost savings for some producers, it is not for everyone.
Because of the inclusion of the cob, husk and shank, there is more variability in nutrients and particle size in snaplage compared to HMSC or dry corn. Variability in the content of non-grain material can vary with plant harvest moisture despite consistent harvesting methods. Snaplage packed and stored in horizontal bunkers will result in a more uniform end product than when blown into upright silos where separation tends to occur. When feeding a high-producing dairy herd, feed consistency is key and a high inclusion rate of snaplage in the diet may not work.
A drawback of snaplage as the sole starch source is the loss of flexibility in the ration. Because of the lower starch concentration of snaplage (usually 60 percent of HMSC or dry corn), it can become difficult to make enough room in the ration to increase starch when needed. When balancing rations, it is ideal to have more flexibility in adding or removing starch via pure grain and to balance fiber needs with forage or by-product concentrates.
Another consideration in using snaplage is the amount, size and moisture of the cob. Many times, cows will sort the cob out of the diet, resulting in a different ration on paper than actually consumed. Optimal harvest for the entire ear of corn should be at 36-42 percent moisture. If harvested too dry, snaplage can be difficult to adequately pack and will result in moldy feed.
In conclusion, harvesting snaplage may reduce feed costs while reducing flexibility in ration formulation and increasing variation in the diet. In deciding to harvest snaplage in place of corn silage and HMSC or dry corn, carefully consider the herd dynamics and feeding programs and include the herd nutritionist in the discussion.