– Dr. Katie VanValin, Assistant Extension Professor, University of Kentucky
When the weather forecast calls for a few days of clear skies this time of year, it is a safe bet that many producers are hitting the hay fields to get hay put up to feed their herd this winter. When thinking about the hay requirements for a herd, I often hear discussions about the number of bales required. However, focusing on the number of bales alone is like only looking at half of the picture. Cattle have nutrient (energy and protein) requirements, not a bale requirement. So really, at the end of the day, it won’t be a certain number of bales that maintain the cowherd at a BCS 5 or greater. Instead, supplying enough pounds of total digestible nutrients (TDN) or energy and pounds of crude protein will meet the cow’s nutrient requirements. The exact amount of TDN and crude protein required depends on several factors such as stage of production, environmental factors, and mature cow size, to name a few.
The single most significant factor that impacts forage quality or the nutrient content and digestibility of the forage is the stage of maturity at harvest. As the plant matures, the leaf to stem ratio decreases, which means a greater concentration of fiber (a portion of which is undigestible) and decreased protein concentrations. Unfortunately, when cool-season forages are rapidly growing in the spring, it can be easy to miss the optimal stage of maturity to capitalize on forage quality. Weather can also have a significant impact on harvesting hay at optimal maturity. While wet springs can be a catalyst for coolseason grass growth, they can also make finding a window to cut hay difficult. However, this spring, we have had several good opportunities to get hay harvested. Luckily, it takes the same amount of time to cut, rake, and bale good quality hay as it does poor quality hay.
It is important to remember that hay is often the base of any of our cattle rations (or perhaps mixed with other forage sources such as silage). The goal should be to meet as much of the cow’s nutrient requirements through the forage as possible and limit the amount of supplement that is needed. The table below shows an example of the cost of supplementation with an 80:20 soyhull and DDGS blend (priced at $210/T) based on hay quality.
As we can see in this example, supplying medium to high-quality hay can go a long way to meeting cow nutrient requirements while minimizing supplementation costs. Getting hay tested will also help ensure that the right hay gets fed to the right cows by matching nutrient concentrations with nutrient requirements. However, the time to truly impact hay quality is before and at harvest, well before it is fed out this winter.