Dairy producers can feed low-starch, high-byproduct diets to late-lactation cows with little loss in milk production, according to a recent collaborative study reported in Cornell and University of Wisconsin Cooperative Extension publications.

Producers faced with limited forage supplies may be considering the use of low-cost feed alternatives in the form of substitute forages and byproducts. But little information is available on formulating dairy rations based largely on these low-starch options.

That’s led two researchers to study how cows are affected when fed a low-forage, low-starch diet using wheat straw and sugar beet pulp as forage substitutes. Less-expensive byproducts, such as corn gluten feed, distillers grains, whole cottonseed and molasses, were fed in place of higher-cost, higher-starch corn grain and soybean meal in late-lactation dairy diets.

Mary Beth Hall, USDA-ARS researcher at the U.S. Dairy Forage Research Center, Madison, WI, and Larry Chase, Cornell University animal scientist, conducted the study. Wheat straw provided “chewable” fiber, and sugar beet pulp provided “fermentable” fiber.

According to the Wisconsin Extension publication, “the experimental diets contained only 40% true forage (corn and alfalfa silages) and differed in the amount of chopped wheat straw or sugar beet pulp pellets they contained, ranging from 0% straw + 12% beet pulp to 9% straw + 3% beet pulp. All other ingredients were kept in the same proportions in all diets. Molasses was included to bind the rations together and reduce sorting. Diets contained monensin.”

On the 40% forage diets, averaging 11% starch, cows maintained 3.5% fat-corrected milk production as compared to a more usual 60% forage diet. However, feed efficiency was lower and income over feed costs was higher on the low-forage, high-byproduct diets.

“Using up to 6% wheat straw gave good performance without noticeable body weight loss/condition change,” according to the Extension summary. But producers who consider using such diets should monitor cow body condition to make sure that the diets are adequate to meet the cows’ energy needs.

Although the stopgap diets may not be as profitable as high-forage diets, they offer a temporary feeding strategy until the next forage harvest.

For more on the study, check out the proceedings of the 2012 Cornell Cooperative Extension Feed Dealers Seminars and the University of Wisconsin Extension Web site at bit.ly/12xThOd