Editor’s note: This is the second in a two-part series on feed additives and supplements. Click here to read the first of the series (More additives, supplements than you can shake a stick at).

Dairy producers and their nutrition advisers have an ever-expanding list of supplements that can be considered when formulating diets. These products include modifiers of rumen fermentation, silage additives, protected nutrients and modulators of nutrient metabolism.

The impact of fiber digestion on dairy nutrition is complex, and all the measurements of fiber digestion listed on the forage report add to the confusion. Understanding fiber digestion requires knowledge of what actually happens in the cow (in vivo) as well as why and how we try to estimate it in the laboratory (in vitro).

Long, long ago and far, far away, crude protein (CP) was used as the sole measure of the protein value of ingredients. Up until some 45 years ago, it was felt that this (CP [N x 6.25], along with total digestible nutrients (TDN) as a measure of energy), was all that was needed to balance a lactation diet.

Cows are designed to use forage. It keeps them productive and healthy. Forage quality sets the limits for how much forage we can feed and the ceiling on how well animals can perform. We include as much in rations as we can while making sure nutrient requirements are met and cows are healthy.

Alfalfa is an excellent source of fiber and an energy-rich, high-quality protein source, making it a staple ingredient in most dairy cow diets.

GE, DE, ME, NEL, NEm, NEg There are a number of key dairy nutrition terms – like gross energy, digestible energy, metabolizable energy and more

Trace minerals are those minerals required by dairy cattle and youngstock in very small amounts – usually at the milligram level per day. The occurrence of trace minerals in forages is largely dependent on the amount of those minerals found in the soil in which the forage is grown.

When low milk prices or high ingredient prices occur, dairy producers look to save money any way they can. Feeding more homegrown forage and fewer purchased ingredients is an available option.

Editor’s note: This is the second part of a three-part series. To read the first part of this three-part series, go to (Corn silage, feeding management, cash-flow effects) Cropping management and corn hybrid selection for silage can be major factors affecting the animal performance needed to maintain a sustainable profit margin.