Don’t leave your forage on the grill too long

By Mike Rankin

My wife does most of the cooking at our house. She is more skilled and discerning than I am when it comes to preparing a meal. My rule of thumb is that if you have to mix two or more ingredients together to get the desired outcome, I’m out. Rather, I prefer to just slop something on a plate and fire up the microwave.

The exception to my culinary involvement centers on the outdoor grill. Of course, as a Wisconsin resident, this takes me out of the food preparation picture for about half of the year.

I enjoy the challenge of grilling and getting just the right amount of “pink” in my steak. I’ve perfected my technique for beef and pork. Chicken, on the other hand, is my Waterloo.

It seems the time difference between a chicken breast that is cooked just right, maintaining moisture and tenderness, and one that ultimately mimics shoe leather for consistency and taste is measured in milliseconds. I admit to getting the latter result far too often.

And so it is with forage crops. If you leave them outside “on the grill” too long, taste and consistency take a hit, especially with first cutting. With forage, it’s all about timing for optimum fiber digestibility.

Although protein is an important component of an animal’s diet, it rarely is the most limiting factor. Energy, on the other hand, often does limit performance. In a forage-based diet, that translates to fiber digestibility and rate of digestion. Your success in this area depends largely on when the mower gets greased.

Admittedly, total fiber content is an important consideration, but how much of that fiber gets digested (or doesn’t get digested) is equally if not more essential to know, especially if being fed to dairy or beef animals that are lactating or growing. Highly digestible forages can boost dry matter intake and cut feed costs in the form of additional supplements.

Digestibility has little cost

Animal performance hinges on fiber digestibility and, in turn, the actual amount of total digestible nutrients derived from the forage. What we know about first cutting is that it can be the highest NDF digestibility forage of the year if it’s cut on time and the lowest if cut late. Like chicken on the grill, the relative time from one outcome to the other is not too long.

High fiber digestibility often doesn’t cost anything; it’s mostly a function of making timely harvest and grazing decisions. Harvesting forage with relatively high fiber digestibility is almost always a net economic winner whether you feed it or sell it.

Though yield and stand persistence are always important considerations, keep in mind that at some point in the plant maturity process the forage yield may continue to climb, but the harvested amount of digestible nutrients declines. It makes little sense to capture yield of additional fiber that won’t be digested.

It is very possible to have high-protein forage that is low in fiber digestibility. Wilting hay that is rained on will often fall into this category. Don’t be fooled into thinking that because the forage has a high protein content that it also has high fiber digestibility.

Variety selection can help

Money spent on forage varieties that have research-proven, high fiber (NDF) digestibility is generally money well-invested. Reduced-lignin alfalfa varieties, with corresponding high fiber digestibility, fall into this category. This is true if for no other reason than providing additional insurance against rain delays.

Grasses are different

As with varieties, selecting forage species with high fiber digestibility will also pay dividends. Meadow fescue, for example, has been shown to be superior to many of its perennial cool-season grass counterparts. Ryegrasses also excel in this regard.

Grasses generally contain both more fiber and also a higher percent of digestible fiber than legumes. To capture the “grass advantage,” stands must be cut early as fiber digestibility declines rapidly once seedheads appear. Highly digestible grass forage is often capitalized on thorough good grazing management but seems less often captured when grass is cut for hay or haylage.

Growing environment affects fiber digestibility. Cooler environments (high elevations or spring growth) will produce forage with higher fiber digestibility than hot environments (desert or summer growth) if all other factors are equal.

Finally, although the USDA hay market grading system doesn’t value fiber digestibility, it doesn’t mean you shouldn’t. Put your money and faith in metrics such as NDF digestibility (NDFD), undigested NDF (uNDF240), total tract NDF digestibility (TTNDFD), relative forage quality (RFQ), or a summative TDN calculation.

Not all livestock classes demand forages with high-fiber digestibility, but striving for such forage still makes good sense. Rare is the year when too much high-quality forage is a problem, so don’t leave your forage on the grill too long.