Incorporating a stearic acid supplement may increase dry matter intake as well as yield of milk components and milk. This is more distinct in higher producing cows. The effects of supplementing stearic acid was observed in regards to feed intake as well as production and metabolic responses of dairy cows who were diverse in their milk production.

The study took place over 21 days and data was collected over the last four days on 32 Holstein cows who had calved more than once and, on average, were 142 days in milk. Each cow was randomly assigned to a different diet treatment based on level of milk yield.

The diets were supplemented with stearic acid (SA: 98% C18:0) or soyhulls (control) for 2% of the total dry matter. All diets included corn silage and alfalfa containing 17.3% crude protein, 25.1% starch and 24.5% (forage) neutral detergent fiber.

When compared with the control, SA increased dry matter intake, milk, fat, protein and lactose yield, 3.5%  fat-corrected milk, plasma insulin, glucagon, glucose, nonesterfied fatty acid concentrations and crude protein digestibility, and typically increased neutral detergent fiber digestibility.

Cows who consumed diets supplemented with SA did not experience a change in the concentration of milk components, feed efficiency, body weight, body score or organic matter digestibility. The SA supplement did have a decreased fatty acid yield response (the extra fatty acid yield secreted in milk per unit of additional fatty acid intake), which is partly associated with the low estimated digestibility of the supplement.

In conclusion, is you choose to integrate a stearic acid supplement as opposed to soyhulls as a supplement in your dairy cows’ diet, there is evidence its introduction has a positive response to milk yield in cows – though it is more noticeable in cows who are higher producing.


Authors: P. Piantoni, A.L. Lock, M.S. Allen, Department of Animal Science, Michigan State University


Link to Journal of Dairy Science abstract: