Expeller soybean meal as a source of rumen undegradable protein for lactating dairy cows

The loss of meat and bone meal as a source of high quality protein for lactating cows creates an increased need for nonanimal sources. Fifty six Holstein cows were used to evaluate expeller soybean meal as a source of rumen undegradable intake (by-pass) protein for high producing cows. Expeller soybean meal tended to improve 3.5% contain fat-corrected milk yield and increased milk fat percentage relative to diets containing either solvent soybean meal or a meat and bone meal:blood meal mixture. In contrast, the protein percentage in milk was depressed significantly when cows were fed expeller soybean meal compared to animal protein. A limiting amino acid (possibly methionine) is implicated