Sustainable, Low-Cost Process Turns Olive Pomace Into Nutrient-Rich Sheep Feed

Within the European Union-funded Thematic European Rural Bioeconomy Network project ( thERBN ), the non-profit organization Deafal and the Agency for the Promotion of European Research (APRE) presented the method as a good practice for small- and medium-scale estates. The innovation lies not in the invention of a new technology, but in the intelligent and integrated use of already known practices applied to these biomasses, which are usually treated differently.” Composed of olive pulp and pit fragments, olive pomace is a residue of olive oil production that requires proper disposal.

Brewer’s grains are a solid residue of beer production, with annual output in Italy reaching about 320,000 tons. The resulting ensiled feed can be easily incorporated into sheep rations without altering production performance.” The system begins with a simple pre-treatment of both byproducts before ensiling.

Olive pomace is separated from the pits, which are recovered and reused as biomass for heat and energy production. Brewer’s grains are dried to prevent unwanted fermentation, extend shelf life and simplify storage and transportation.

A portion of the dried grains can as well be used as an energy source. The two components are then mixed and ensiled.

A portable concrete mixer, not traditionally used for ensiling, can be adapted as a low-cost mixing device. Mixed and ensiled, olive pomace and brewer’s grains produce a feed that can be incorporated into sheep rations, providing fiber, bioactive compounds, protein and readily available energy. (Photo: Paola Cassiano) During this phase, the grains act as an absorbent substrate, promoting lactic fermentation and helping regulate the silage’s overall moisture content. Trials conducted by the working group found the resulting feed had a balanced nutritional profile and high digestibility.

It was also palatable and well accepted by animals, with no negative effects on milk quality or sheep expansion compared with conventional feed. She added that a key feature of the process is replicability.

Designed for small- and medium-scale holdings, it is compatible with existing silage facilities at the estate or cooperative level. Does not require complex or large-scale equipment. “A key advantage is that these byproducts can be either generated in-house or sourced from neighboring farms, helping offset both logistical and feed costs for all the producers involved,” Spinelli observed. Reducing feed costs is one of the most significant outcomes.

Preliminary data show that introducing the mixed silage into sheep rations at 25 to 30 percent, alongside other feeds, results in an average cost reduction of about 27 percent. The ecological footprint is also reduced thanks to limited logistics and since ensiled pomace has a lower environmental impact than conventional lipid and fiber concentrates such as corn and soy, which in addition compete with human nutrition. A group of producers in the Lazio region has recently joined the effort, adopting the ensiling process.