Editor's note: The following case was handled by Robert Fry, an independent nutritionist with Atlantic Dairy Management Services from Kennedyville, Md.
Robert Fry, an independent nutritionist from Maryland, recently had an “ah ha” moment when he was formulating a ration for a client.
This 300-cow herd that Fry was working with fed corn silage, sorghum silage and wheat straw for forages. Grains were soybean meal, amino plus, ground barley and ground corn. In addition, a vitamin and mineral pre-mix was fed.
Inventory on the ground corn and barley was depleted and high-moisture corn was now available, so the ration needed to be reformulated.
Prior to reformulating the ration, new forage samples were taken. The forage samples showed similar results as previous samples. Fry went ahead with the diet reformulation. The percentage of forage in the diet went down and the percentage of protein in the diet went up considerably. The basal diet was 16.8 percent protein, yet the newly formulated diet had more than 18 percent protein. “A protein percent that high is unacceptable in our area due to the environmental issues with the Chesapeake Bay,” explains Fry.
To resolve the protein problem, Fry went back and looked at the new forage analysis. After a second review, he noticed that the starch level was slightly higher than before. Starch seemed to be at the root of the problem. High-moisture corn has a higher starch value than the barley and corn in the previous ration. “The maximum level of starch I was willing to feed in this diet was 28 percent,” notes Fry. “Because the forages were of mediocre quality, a lot more high-moisture corn was coming into the diet. I was hitting the upper limit on starch, but I still didn’t have enough energy in the diet to meet the cows’ needs.”
To meet the energy needs and reduce the amount of protein fed, Fry decided to add an additional amount of bypass fat. “As soon as I offered the additional fat, the diet was able to balance,” he says.
Fry says he had an “ah ha” moment while wrestling with the diet, trying to get it to balance. “It hit me: I needed to make sure I was offering alternative sources of energy such as fat, starch and sugar, so the computer can balance the ration. I have to remind myself the computer can’t think.”