Dietary strategies to improve rumen activity 

10/03/2025

Another issue, volatile fatty acids, are the main energy source of ruminants and their production is closely related to the animal's efficient use of feed. Volatile fatty acids undertake the task of transferring nutrients into the blood through the rumen wall. Another task is to provide a constant and optimal rumen pH for digestion, thus providing conditions that will increase their own absorption and reduce the risk of acidosis.

Effects of rumen activities on immunity

In addition to the functions of utilizing nutrients and producing energy, the rumen is known to have regulatory effects on the animal's immune system. For example; it has been observed that correctly balanced nutrition programs reduce parasite load and increase plasma immunoglobulins (antibodies). On the contrary, it has been observed that poorly balanced diets change the microbial population of beneficial bacteria, creating a rumen environment that provides a habitat for harmful microorganisms, including gram-negative bacteria, which in turn causes bacterial deterioration in the large intestine.

In addition, it is known that low rumen pH causes deterioration on the rumen epithelial surface and causes passive transfer of harmful compounds released as a result of the bacterial deterioration we mentioned. This transfer does not only have negative effects on the animal; it also causes nutrients and the energy released to be spent on the formation of the immune response.

The rumen holds the key to productivity

Diet is the element that creates the strongest positive effect on rumen function, but another important point that is equally important is the animal variation that will ensure that the microbial communities in the rumen, especially the microorganisms associated with the rumen wall, have a common profile. Because different animal breeds have different ways and capacities to give immune responses leading to energy and nutrient breakdown. On farms, there are very few people who can minimize this animal variation. In any case, an efficient rumen means a healthy, productive animal. A healthy, productive animal means a profitable business.

Effective Diet Strategies

In the name of studies to increase rumen health and function, some different dietary strategies have been examined using specific nutrient contents. For example; in heifers that need limited but high energy nutrition, developing dietary strategies is seen as an effective way. A 14.5-month-old Holstein heifer weighing approximately 340 kg was fed high-energy feed at 1.25, 1.5, 1.75 and 2.0 percent of its own body weight. These animals were able to benefit from a ration containing high-energy feed at a maximum of 1.25% of its own body weight. In this example, feeding the heifer a ration containing high-energy feed at a rate higher than 1.25% of its own body weight would unnecessarily increase costs.

Energy-rich diets can be given to dairy cows in the transition from the dry period to the lactation period in a balanced manner to compensate for the decreased dry matter intake. These diets generally contain high starch and pose a risk in terms of rumen stability due to rapidly decreasing rumen pH and bacterial deterioration starting in the large intestine. In addition, animals should be given time to adapt to rations with high starch (grain) content during this period. In addition to all these, the use of easily degradable (fermentable) starches and fibers in the ration will also increase digestibility.

Additives facilitating fiber digestion

In order to increase rumen function; the use of feed additives such as buffers, yeast, plant extracts, enzymes and unsaturated fatty acids and specific feed ingredients are of great importance in terms of dietary strategies. For example; buffers have been used in rations for many years to increase rumen function and to intervene in possible pH decreases. The most common example of buffers is bicarbonates. However, we will discuss more “natural” additives that are accepted today and prevent pH decreases.

Yeast and probiotics (such as Lactobacillus species) are additives that are increasingly included in cattle diets to enhance fiber digestion and stabilize the rumen environment. Yeast cells tend to bind to newly ingested food particles. It is thought that this tendency is due to the binding of oxygen in the rumen to the same food particles. Yeasts begin to utilize oxygen, thus eliminating the threat to the anaerobic environment. Many improved strains of Saccharomyces cerevisiae are the main yeasts used in ruminant diets. At the same time, live yeasts can produce functional compounds that can be used in rumen metabolism, such as peptides, lactate-utilizing bacteria that remove lactate from the environment.

Exogenous fibrolytic enzymes also show promising results in enhancing fiber digestion, but more studies are needed to be able to say for sure.

Plant extracts have recently become the most interesting topic. Tannins and saponins are the two main groups studied. These two main groups include substances that will reduce protein breakdown in the rumen and provide direct digestion and absorption in the small intestine. However, both are thought to have negative effects on some other aspects of rumen functions. All of this means that plant extracts may increase the risk of acidosis.

Volatile fatty acids have shown promise in many studies. However, as with plant extracts, their negative effects on some bacteria are still a matter of concern for researchers. In terms of their general effects, volatile fatty acids reduce protein and starch breakdown in the rumen, but most likely also disrupt the chemical nature of the rumen fluid content. Highly unsaturated fatty acids are also known to have negative effects on fiber fermentation in the rumen. Despite this, they are also of great interest due to their positive effects on reducing enteric methane production, as seen in many studies.

Protein is the key ingredient

Protein is still the most important element in rumen efficiency, although it is not the only issue that is emphasized. Microbial proteins are considered the most costly protein sources. The main reason is that it is the source that most closely resembles the amino acid profile of milk and meat. Accordingly, the continuous nitrogen supply of rumen microorganisms and the energy they will obtain from this nitrogen will result in higher amounts of microbial protein production due to higher rumen efficiency. Recently, there has also been an awareness of overfeeding with crude protein. In practice, if we are talking about the ration of a lactating cow, 100 grams of crude protein should be targeted for each liter of milk produced.