Maintaining Milk Solids Through the Grazing Season
As herds transition into spring grazing, maintaining milk solids becomes increasingly challenging. High intakes of fresh grass typically reduce effective fibre in the diet while increasing rumen passage rate and the rate of rumen fermentation. This alters volatile fatty acid (VFA) production, often reducing acetate supply and increasing the risk of rumen instability. The result is a well-recognised seasonal pattern: declining butterfat percentage and greater variability in milk solids, particularly in high-output herds.
On many farms, this presents as a reduction in butterfat of approximately 0.20–0.30 percentage units from early to mid-season, alongside less consistent day-to-day performance. While often considered inevitable, this reflects a shift away from the rumen conditions required to support optimal milk fat synthesis.
Maintaining milk solids during this period requires a dual approach. Firstly, ensuring an adequate supply of fatty acid precursors to support milk fat synthesis. Secondly, maintaining rumen conditions that favour fibre digestion and acetate production despite rapidly changing forage quality.
Mazz Butter Booster is formulated to support both of these requirements. By combining a targeted fatty acid supply with rumen support, it is designed to help sustain milk solids production from forage-based diets while supporting butterfat percentage during periods of nutritional pressure. Its combination of rumen-active ingredients and highly available energy sources helps support fibre digestion, stabilise rumen fermentation and improve the supply of key milk fat precursors during periods of high grass intake.
Last spring, a progressive dairy farm in southern Ireland focused on maintaining milk solids while driving output from grazed grass. Despite higher milk volumes in 2025 — an increase of more than 6,900 litres between March and May compared with the previous spring — butterfat performance remained comparatively stable through the grazing transition, while milk protein levels improved consistently year-on-year.
A key feature of the 2025 performance was the ability to maintain strong milk solids while operating at a significantly higher level of milk output. Total milk supplied between March and May increased substantially year-on-year, yet butterfat performance remained comparatively resilient through the grazing transition, while protein levels improved consistently across the period.
In practical terms, this reflects efficient conversion of grazed grass into milk solids, rather than simply driving additional litres at the expense of component performance — a challenge commonly encountered in high-output grazing systems.
From a commercial perspective, this consistency is critical. Small, sustained reductions in butterfat percentage can significantly impact milk value over the course of the grazing season. Maintaining solids allows for more efficient conversion of grazed grass into saleable output, while reducing variability in milk cheque returns.
This approach is particularly relevant in herds pushing for high performance from grass, where the balance between intake, rumen function and milk solids is most finely tuned.
Supports solids. Maintains performance.
