Liquid feeds can be considered a functional food since, in addition to having a nutritional role, they contribute positively to one or more physiological functions for the animal body (ILSI Europe Concise Monograph, 2002). Liquid feeds contain several sources of sugars and organic acids and bring specific benefits to the rumen health.

  • A more constant pH
  • Favoring cellulolytic bacteria
  • The development of the ruminal papillae


There are about two hundred species of bacteria in the rumen capable of degrading the different substrates supplied to the dairy cow to obtain nutrients. There are also protozoa and at least three species of anaerobic fungi (Bertolami, 2012). The rumen microflora is therefore a population in continuous development and capable of adapting to the foods administered in ration, in order to be as efficient as possible.
Providing different sources of sugars in the diet of dairy cows therefore allows us to fully feed the various microorganisms that populate their rumen, facilitating the food degradation processes.
The digestion of carbohydrates and fiber can be divided into two phases: one extracellular and one
intracellular. In the first, the bacteria use enzymes to attack cellulose, hemicellulose, starch
and sugars with the formation of glucose and fructose; in the second phase the obtained monosaccharides are
absorbed and used by bacteria to produce energy and carbon chains useful for their protein synthesis. Furthermore, the fungal population that lives in the rumen (about 10% of the microbial mass), is capable of degrading the structural barriers of plants and of producing high levels of cellulase and hemicellulase, enzymes capable of splitting fibers (Akin and Borneman, 1990). Mushrooms use as an energy source: cellobiose, fructose, glucose and lactose (Phillips, 1988).


Over the years, various studies have been conducted on the use of the different sources of sugars that can be used in the diet of dairy cows: all have confirmed that it is necessary to reach a ration share of 7 – 8% of sugars. In support of these theses, the results obtained by Palmonari et al. in 2018 (In press). In this study, the digestibility of fiber was analyzed in cows fed with differently added rations: in a group with sucrose, in a group with molasses and in a group with a mixture of sugars and organic acids, sugars and organic acids. In all three cases an increase in digestibility was observed, but the best results were seen in the third  group. The use of different sources of sugars added with organic acids has allowed this group to satisfy the needs of the rumen microflora more fully and has reported a + 25% in the digestibility of the fiber.
The mucosa of the rumen presents an epithelium provided with numerous and long papillae, whose role is that of increase the available absorption surface in the rumen (Bertolami, 2012). In adult cows it development of the papillae is promoted by butyrate, which creates the conditions for a better assimilation of nutritional principles. Butyric acid is a volatile fatty acid (AGV) present in the rumen and produced by butyric bacteria starting from simple sugars. A diet rich in soluble sugars, for example when young herbs or molasses are administered, can lead to an increase in butyrate production (Palmonari et al. 2020).
It is therefore clear how, beyond the nutritional aspect of sugars, there is a positive functional role on the physical well-being of the rumen with a direct
consequence on the health of the animal. In addition, well-developed ruminal papillae allow to make the most of the ration administered, increasing the nutrient absorption surface.


Liquid feeds, containing different sugar sources mixed with organic acids, perform more the role of functional foods than single sources of sugars, since they are able to concentrate the benefits of each single component they contain in a single product. A healthy rumen is synonymous with a healthy cow that will be able to make the most of its genetic potential, guaranteeing greater feeding efficiency and therefore higher than average yields. Surely a healthier and more efficient cow will be able to make the most of the ration administered, assisting all the physiological processes of the rumen. Processes that will reflect on a positive energy balance, which will increase the cow’s fertility.