By Ben Beckman
Fungal diseases have made noticeable impacts on corn fields in Nebraska this year. As these fields open for grazing following harvest, many are wondering if disease pressure affects how we manage livestock on those acres.
Diseases like tar spot, southern rust and other fungal leaf diseases create lesions on corn leaves, weakening the plant in the process. Severe infections can cause leaves to senesce earlier, limiting photosynthesis and reducing the amount of leaf material left after harvest. Stalk rots can also weaken plants, increasing the potential for lodging.
So, what does this mean for grazing residue? Overall residue quality may be somewhat lower, but the bigger concern is that there may simply be less leaf material left. Along with husks, leaves are the primary component of residue-based diets. Their loss, therefore, can indirectly lower overall residue feed value. In addition, earlier senescence and existing tissue damage may allow corn leaves to weather and decompose faster than normal — shortening the window of quality grazing even further.
Stalk rots can also increase harvest losses from lodged corn, potentially leaving more ears or grain in the field. This is something to watch for when turning cattle out to graze, especially if excess grain is enough to cause acidosis.
Source : unl.edu