Dairy cattle

Protein ingredients for dairy rations

Soybean meal is a recognized plant-protein feed for dairy cattle. Its role is not determined by crude protein alone: ration decisions also depend on the cow’s needs and how the protein contributes to nutrient supply, including essential amino acids. Compare a lot’s analysis with the rest of the ration rather than assuming one protein source suits every formulation.

Clarify what “thistle seed” means

The name can refer to different species and product forms. Whole seed, ground seed, oil, meal, cake or expeller, and extracts are not interchangeable. Research on milk thistle meal—the residue after oil extraction from milk thistle seed—does not establish the feed characteristics of every product called thistle seed.

Milk thistle meal has been evaluated as a potential protein feed, but the evidence does not support treating it as a direct replacement for soybean meal. Differences in fiber and other nutrient characteristics make product identity and ration-specific evaluation important.

Compare lots for the intended ration

For soybean meal or a proposed alternative, request a current lot analysis and review relevant measures with the dairy nutritionist. Depending on the formulation, these may include moisture or dry matter, crude protein, fiber fractions, fat, and protein degradability or amino-acid measures. For thistle products, first establish species, processing method, and whether the specific product is intended for feed use.

Common questions.