The feeding of silage has now become common practice, especially among dairymen, and in humid United States, corn is the standard silage crop. There are, however, two distinct types of farm practice in growing silage which distinction should be made clear at the outset. In the corn belt and adjacent sections, the problem is one of handling the corn crop in the most economical way. Experience and investigation have shown that the silo fills this need. On the other hand, in sections where dairying is a highly specialized industry, the problem is that of securing enough roughage, the concentrates being largely purchased. This is especially true in the northeastern states, but also holds for many other northern regions. In sections where tillable land is limited, this problem becomes even more acute. It was from the second point of view that this study was undertaken.

Under such conditions, many farmers have chosen late varieties of corn that do not mature before frost, thus securing large tonnage, but little grain, the corn being of low dry matter content. The weight of opinion among college and station workers has been against this practice and in favor of varieties that would mature or nearly mature. Several carefully conducted investigations, notably that of Jones and Huston (1), furnish conclusive evidence that a given variety produces the maximum dry matter at about maturity. From the corn belt standpoint as defined above, therefore, the question would seem to be settled. Where crop production and dairying are not intensive, the standard grain varieties should probably be grown for silage, and "cut when the husks begin to dry."

*Resigned, November, 1923.

In this investigation we have attempted to answer the question raised by the large group of dairymen producing on an intensive basis-"Shall we plant early, medium or late varieties of corn?" not "At what stage shall a given variety be harvested?" The problem may also be stated, "Which will produce the most milk per acre, early, medium or late maturing varieties?"

A search through experiment station literature brings to light the fact that this is not a new problem. The question was debated in many states when the silo was first introduced into this country, the following statement by Dr. Jordan in 1893 (2a), bearing this out. "The most common question asked in this connection is, which are the most profitable varieties to grow, the large, which mature in a latitude south of New England, or the small which complete their growth in this climate?"

Jordan in 1893 reports a field, comparison of "Southern White immature," 15.20% dry matter, and "Maine Field -mature," 21.09% dry matter. "The Field corn is in this case, worth 40% more than the immature Southern White, pound for pound, judging simply by the dry matter. The great bulk of the Southern corn is not proof of greater or equal value."

Jordan later reports (2b) field tests covering five years. The digestion coefficients were determined by trials with sheep.

The

The

In 1892-1893, a feeding trial was made with five cows. silages were fed on an equal digestible dry matter basis. conclusions drawn are

When compared pound for pound, the difference in feeding value was practically in proportion to the digestion coefficient, that is 65 to 73. When compared on an acre basis, they were practically equal, 3,251 lbs. for Late, and 3,076 for Early. Dr. Jordan then stated:

VARIETIES OF SILAGE CORN FOR MILK PRODUCTION

"The yield of digestible dry matter has averaged 175 lbs. more per acre with the Southern corn. To offset this, it has been necessary to handle five and three-fourths tons more weight."

One of the first problems undertaken at the New Hampshire Station was a comparison of corn varieties for silage. Whitcher (3) gives the following, based on one field and feeding trial. All varieties were planted and harvested on the same dates.

An attempt was made to compare the corns on a cost basis and the farmer is advised to grow "precisely the same variety of corn as is used for planting fields to be husked." But the yield of the Flint corn is abnormally high and one doubts the soundness of the field technique.

Hills (4) reports in 1903 a two year field and feeding trial. Quoting from the conclusions-"The large corns look impressive, but they yield but little and often no more actual food value than do some of the smaller varieties."

Roberts and Wing (5) report in 1890, a single field test of 41 varieties of corn from which the following are selected:

They conclude "Care should be taken to select the largest variety that will ripen before frost."

Lindsey and Smith (6) at Massachusetts in 1906, made a special study of Eureka as compared with Pride of the North. All data is on the corn as harvested. Digestion trials with sheep were made on both varieties.

Under conclusions, they advise against the use of Eureka, arguing that the actual food material is the same and the excess yield of Eureka is water.

The above covers the early work in the East. Without exception, the late varieties are condemned. However, on turning to reports from the Middle West for the same period, we find different conclusions.

Shelton (7) in 1889 reports field trials at Kansas of thirteen varieties for silage. They range from very late dents to flints like Sanford. All were planted and harvested on the same dates. Dry matter percents are not given. The following quotation is of interest-"For this State an ensilage variety should mature late-the later the better, as a late sort will furnish more feed from a given area."

Porter (8) at Minnesota in 1889 conducted a single feeding experiment to compare the value per acre of early and late varieties of corn. The silages were fed on an equal dry matter basis and the conclusions are:

"For Fattening Cattle. Our experiment shows that we received more value per acre from the Flint than from the Southern Corn Ensilage."

"For Milk. The Southern corn produced one-third more dry matter and this proved nearly equal, pound for pound, to the dry matter of the Flint Corn."

"Grow those kinds of Dent that are slightly too late to ripen." The data given shows an abnormally high yield for the late variety which would affect the conclusions.

Hays (9) in 1894, reports more extensive field and feeding trials at Minnesota and finds the dry matter in silage from an early dent and a late dent, "about equal in feeding value for milk and butter production." He further states, and this is the only case in the early literature where the problem of roughage is recognized, "Where a large amount of silage is

VARIETIES OF SILAGE CORN FOR MILK PRODUCTION

wanted from a small area to feed with cheap mill feeds, these results indicate that the most feed can be procured by using, in any given locality, corn so large that it will barely pass the roasting ear stage before frost."

There seem to be no further early data from the Middle West, but it is interesting to note that the conclusions drawn are opposed to those of the eastern stations. Two more recent station publications are of interest, both from the Middle West. Williams and Wilton (10) report field trials at Ohio in 1914 as follows:

Blue Ridge

Ohio Leaming

Quoting from the discussion:

"It will be noted that varieties adapted to the growing of grain, because they may be expected to come to complete maturity, do not furnish as large an amount of nutrients per acre as the larger varieties. Attention should be called to the fact that more water will have to be handled with the larger corn."

"In intensive dairying, where it is a problem to secure enough roughage, the silage corn will likely prove more satisfactory. In the corn belt sections where the problem is to take care of the corn crop, the field corn will doubtless prove more satisfactory."

Cox and Duncan (11) in discussing varieties for Michigan, make the following statement:

"Extremely large growing types, such as the Red Cobb Ensilage, furnish a large yield per acre of silage material, carrying a much higher water content and less food value than silage of greater maturity. The dairyman, living near large cities with a limited acreage, who buys most of his feed, may find these types of use in giving him the largest yield of succulent roughage per acre on his high priced land. The average dairyman and farmer, however, usually has plenty of land and is more limited in silage space and desires to save as much as possible on concentrates. For him, a thrifty variety which