In the wintertime when cattle are grazing cornstalks, they are often lacking the required nutritional content to meet maintenance requirements. This along with cold weather stress can cause loss of condition. During this time, it is essential to know the quality and quantity of available cornstalks and body condition score of cows grazing cornstalks. This information should be analyzed, then utilized to create a supplementation program, if necessary.
The first factor is the quality and quantity of forage available. The amount of corn, leaves and husks varies with growing and harvest conditions. Cattle will select the grain and the best quality forage first when initially turned into a field.
As cattle continue to graze, diet quality decreases, and once cattle have grazed off all husks and leaves, they begin eating stalks and the quality of diet decreases drastically. Weathering will deteriorate forage quality. Cool, dry weather conditions in the fall and winter will maintain quality for longer; while wet, warm, muddy conditions will result in more rapid deterioration of leaf and husk.
The second factor is cow body condition score at the initiation of grazing. Research at the University of Nebraska indicates that mature, spring calving cows in a body condition score 5 or better do not need supplemental protein or energy when grazing targets removal of half of the leaves and husk based on corn yield.
Bred two-year-old heifers in their third trimester as well as lactating cows will have higher nutrient requirements. These will need both protein and energy supplementation to meet their nutrient requirements. Spring calving cows in a body condition score less than 5 would likely benefit from protein supplementation.
The most effective way to develop a supplementation program, is to first identify the nutrient(s) that are limiting productivity and then how to provide those nutrients at the lowest cost of input. It is equally important to identify what they do not need, thus eliminating additional costs of supplementation.
Frequency (daily, three times a week, once weekly) of feeding supplements may affect animal response. Feeding lower levels of energy or protein more frequently decreases fluctuation of cornstalk intake. However, feeding high-protein supplements once a week results in no significant reduction in performance when compared to feeding supplements three times week or daily. Along with reduced transportation and labor costs. Research suggests that protein supplements (≥30% CP) can be delivered as infrequently as once or twice/week, while energy supplements (≤20% CP) should be offered no less than every other day.
For more information on Nebraska Beef Extension or supplementing cows on cornstalks reach me at my office (402) 624-8007 or follow my twitter page @BigRedBeefTalk for more information on Nebraska Beef Extension.