Producers are considering different rations than “normal” due to the dry summer conditions and lack of hay supply. However, corn silage seems to be in abundant supply in some parts of the state. I have received numerous calls asking how much corn silage can I use and what is the minimum amount of hay that a cow needs. 

A research project that I completed at Purdue University evaluated limit feeding corn silage to meet the nutrient requirements of the beef cow.  We found out the limit feeding corn silage can be a good option for overwintering beef cows. As you know corn silage typically has higher energy than the typical beef quality hay, so the cow’s energy requirements will be met with less total dry matter intake of silage compared to a hay diet. However, protein supplementation may be needed, depending on the protein content of the silage. The specific amount can only be determined by testing the feedstuffs and then balancing a ration. Also, with the drought conditions this summer, it is important to test the corn silage for nitrates.

We also studied replacing part of the hay in the diet with corn. The diets were 0.5, 1.0, or 2.0% of the cow’s body weight as hay plus corn to meet the cow’s nutrient requirements. We found that the 0.5% BW of hay plus corn had the same performance as the 2.0% BW of hay treatment. At calving time the cows were in similar body condition and no calving problems were found. However, we did learn the importance of good fences. The 0.5% and 1.0% hay treatments met the cows’ nutrient requirements, but did not completely satisfy their appetites, so the cows were hungry during the adaptation period. All of these treatments were balanced for energy and protein to ensure the desired performance. During the research project, we made sure that all of the cows had adequate bunk space. 

We fed these rations as a total mixed ration using a mixer wagon. Some producers may not have a mixer wagon, so limiting the hay supply with this method may be difficult. Warren Rusche, SDSU Extension Cow/Calf Field Specialist, wrote an iGrow article on limiting hay supply through limiting the time cows have access to the hay, which might be a useful strategy for producers limited by their equipment inventory.

Source: Julie Walker