Effect of roasted soybean grain compared to lignosulfonate-treated soybean on performance of lactating Holstein cows

The use of roasted soybeans in the diet of dairy cows is common, but the roasting temperature and its effect on cow performance and protein fraction of diets have not been fully understood. To eliminate the antinutritional substances and increasing bypass protein, soybean seeds are processed, and heat is the most common way used to processing soybeans. The main objectives of this research were the estimate of the effect of soybean roasting temperature on protein fractions of diets, dairy cow performance, and economical comparison between roasted soybean and lignosulfonate-treated soybean.
To evaluate the effect of soybeans roasted at different temperatures on feed intake, milk yield and composition, 8 mid-lactation Holstein cows, averaging 92 ±14 days in milk and 42.9 ±3 kg of milk/day were assigned to a replicated 4 × 4 Latin square design. Control treatment contained lignosulfonatetreated soybean meal and calcium salts of fatty acids, and treatments 2, 3, and 4 contained soybean grains roasted at 115, 130, or 145°C, respectively. The total mixed rations included 40% forage on a dry matter basis and 60% concentrates.
Dry matter intake (DMI) tended to be greater for control treatment compared with the roasted soybean treatments (P=0.08). Actual milk and 3.5% fatcorrected milk yield was greater for control diet than for roasted diet (P The results of this research showed that cows fed control diet had higher DMI and milk yield than cows fed roasted soybean diets. Among different roasting temperatures (115, 130, and 145°C), soybeans roasted at 115°C led to higher milk production and lower DMI. The moderately degraded true protein had the most important fraction between different fractions of protein and highest correlation with DMI and milk yield and composition.