Jan. 1971

FEEDING BLIGHTED corn TO HOGS
AS-394
by James R. Foster
Southern corn leaf blight is a fungus disease caused by Helminthosporium maydis. Although this disease has been present in corn fields for many years, it has never caused widespread damage. However, a new strain of the fungus emerged in 1970 resulting in a massive outbreak of southern corn leaf blight. Wet, humid conditions and high temperatures further contributed to the problem. The fungus, H. maydis, produces a toxin that causes damage to plants but not necessarily to animals. Swine producers are concerned about the effect of the blight on the feeding value of corn.
Experiments Show Little Reduction in Feeding Value
Research conducted with swine and laboratory animals in a number of states indicates very little adverse effect on the feeding value of blight-infected corn. The degree of blight damage in the corn used in these experiments ranged from mild to severe. The blighted corn in most of the trials could be characterized as having lower test weights and containing slightly more crude protein and fiber and somewhat less energy compared to normal corn.
One Indiana feed manufacturer has reported the chemical composition of 15 samples of blighted corn harvested in late September and early October. Table 1 shows a summary of these analyses in comparison to the average composition of No. 2 shelled corn.
Table 1.
Nutrient Content of Normal and Blighted Corn
a slightly reduced energy value.
Blighted corn has been evaluated in swine experiments at a number of universities including Florida, Georgia, Illinois,• Kentucky, Ohio State and Purdue. A description of the corn used in these trials is presented in Table 2.
A brief summary of the results of swine trials at various universities follows. The name of an animal scientist associated with the research is listed for each State.
Florida (G.E. Combs): Two trials were conducted— one with heavy hogs and another with light hogs. The control group in each trial was fed corn with slight blight infestation and compared with similar hogs fed corn with considerable blight damage. Gain and feed efficiency were essentially identical on the two corns in both trials.
Georgia (R.W. Secrley): Blighted corn and normal corn were compared in a swine experiment. After 10 weeks on experiment there were no significant differences in either rate of gain or feed efficiency between the two groups.
Illinois (A.H. Jensen): Young pigs fed blighted corn gained slightly slower, but converted feed more efficiently (2.16 vs. 2.06 lb. feed per lb. of gain) compared to pigs fed normal corn. In a second trial when pigs were given the choice of normal corn or blighted corn on a free-choice system, they consumed about three times as much of the blighted corn as normal corn.
Kentucky (M.D. Whiteker): Pigs were fed various levels of blighted corn for seven weeks. In the five ration treatments normal and blighted corn were blended so the blighted corn made up 0, 25, 50, 75
Table 2. Description of Normal and Blighted Corn in Experimental Rations
Cooperative Extension Service, PURDUE UNIVERSITY, Lafayette, Indiana
SWINE nutrition