Dry matter content should be determined on a regular basis in order to know the amounts of high-moisture feed (silages) to offer or include in your TMR, notes Charlie Stallings, Virginia Tech extension dairy scientist. This can be done weekly or more often, usually depending on farm size. In addition, the nutrient profile (protein, fiber, energy, and minerals) needs to be determined by a commercial lab on a regular basis.

“In the past, we usually recommended testing every four to six weeks or when feeds changed,” says Stallings. For a 50-cow herd, sampling once a month is acceptable. However, a 1,600-cow herd could justify testing three samplings every four days or 21 analyses a month. A 400-cow herd could justify three samplings every seven days or 12 analyses a month.

Wisconsin researchers have modified these recommendations and suggest that sampling every 10 days in the 400-and 1,600-cow herds will result in adequate quality control. They did suggest that duplicate samples be taken at each sampling for a total of six per month on which to base changes to rations.

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