Pilot scale silage production from olive pomace 

Massive amounts of waste and byproducts are produced annually by the food and agricultural industries and are disposed of in adjacent open fields, endangering the environment. The circular economy suggests using food leftovers for beneficial uses such as animal feed. Using less common animal feeds derived from leftovers could provide farmers with a variety of environmentally friendly feeding options. Ruminants feeding with by-products would increase the milk output and, at the same time reduce the need for green plants (straw) in the ensiling procedure and the feeding cost. A form of animal feed known as silage is created from green foliage crops that have been preserved by fermenting them to produce acids. It is usually made from grass crops like maize, sorghum, or other cereals. Olive mills are a promising by-product that can be added instead of other materials and produce a high-quality animal feed. Olive pomace was provided by a two-phase olive oil mill and was separated from olive stones. In this study, the silage production at a pilot scale was examined.  Approximately 1.2 tons of olive pomace, 0.2 tons of straw, 10 kg molasses, and 2.4 kg urea were used. The material was packed in 20 kg bags and sealed airtight. The pH values were between 4.5 to 5 for the whole year and nitrogen content was about 0.85 g TKN/ kg silage dry matter. The fiber content of silage increased during the ensiling period by about 7 and 17% for NDF and ADF, respectively. In the ensiling process, volatile fatty acids (VFAs) play a critical role in the preservation and stability of the silage. The content of lactic acid increased to 1.6 g/L suggesting that the ensiling process with olive pomace is a promising sustainable option. keywords: silage; food waste; olive oil pomace; molasses; urea.  Funding: «This presentation is implemented in the framework of "Olive pomace’s conversion to animal food additive - Μ16ΣΥΝ2-00255" project, and was funded by the Sub-Measure 16.1 – 16.2 – Establishment and operation of Operational Groups (O.G.) of the European Innovation Partnership (EIP) for agricultural productivity and sustainability/ Action 2 – Implementation of the Operational Plan (project) of the EIP Operational Groups for the productivity and sustainability of agriculture»