Managing ruminant gut health
Gut health is essential to the ruminant for optimal health and functionality. When nutrition is mismanaged, the delicate microbiome of the rumen and digestive tract are quickly compromised and the animal is less productive and may experience health issues like acidosis.
Maintaining this microbiome requires more than basic forages. These should be fed with a high plane of nutrition and, when necessary, supplements and feed additives to promote consistent pH levels.
As antibiotics are phased out as growth promoters in livestock production for different countries, exploring innovative and affordable ways to regulate rumen microbial fermentation becomes essential. In recent years, natural feed additives including probiotics have garnered interest for their potential to enhance rumen fermentation effectively and sustainably.
Of course, their effectiveness depends on the individual product, its concentration in the diet and how it is fed and managed within the animal’s unique rumen microbiome.
The ideal microbiome
Proper nutritional management, especially during transition periods, is crucial so the gut continues to function flawlessly without extreme changes in the microbiome.
Keeping the gut bacteria happy is all about balance coupled with a consistent pH level. When an animal is under stress or immunocompromised, it isn’t uncommon for this intricate microbiome to become compromised with many of the beneficial microorganisms dying off en masse. Knowing how to offer support during these times, and preventing imbalances, will help to maximise health and digestion.
The rumen is a complex microbial ecosystem that hosts abundant bacteria. The rumen microbes are depended upon the breakdown of structural carbohydrates in addition to the synthesis of volatile fatty acids (VFA) and microbial protein.
A nutritionally balanced diet is essential for creating an environment that optimises microbial growth and activity in the rumen. The rumen pH is generally stable, around 6–7, though it can fluctuate based on diet. Certain fatty acids, like propionate and butyrate, are particularly valuable as they can be absorbed through the gut wall, providing the ruminant with an energy source. The large amounts of saliva produced by the ruminant help buffer the rumen’s pH, as it contains sodium, potassium bicarbonate and urea. This saliva is swallowed into the rumen and then absorbed through the rumen walls. Ammonia produced during fermentation supports microbial growth and further helps to maintain pH stability in the rumen.
Diets involving high levels of grains and concentrates alter this microbial ecosystem. In turn, this increases the rate of fermentation for short-chain fatty acids. When mismanaged, these short-chain fatty acids can exceed the ability of rumen fluid buffers to properly regulate the ideal pH level which may lead to acidosis.
Probiotics, rumen buffers and other gut-related supplements
Probiotics are one of the most common supplements offered to ruminants. These are live microorganisms that balance the microbial community.
Common probiotics include the organisms Lactobacillus, Bifidobacterium and yeast (Saccharomyces cerevisiae). When fed properly, they can enhance feed intake, weight gain, and milk production by optimising nutrient absorption and stabilising rumen pH.
“In calves, probiotics have been linked to reduced diarrhoea and improved immune responses, while in dairy cows, they can increase milk yield and efficiency,” according to IntechOpen – Open Science Open Minds.
Probiotics can be enhanced with prebiotics which are “non-digestible fibres that promote the growth of beneficial bacteria, play a complementary role to probiotics….They improve nutrient utilisation in both the upper and lower gastrointestinal tract, enhancing digestion and gut motility.”
The combination of probiotics and prebiotics to create a synergistic effect to potentially reduce pathogenic bacteria is referred to as synbiotics.
Rumen buffers are what maintain a stable pH in the rumen which is crucial because fluctuations can lead to issues (like acidosis). A common rumen buffer is sodium bicarbonate, and yeast-based products like Saccharomyces cerevisiae have been shown to reduce the risk of acidosis by stabilising rumen pH and enhancing fibre digestion.
“Various studies have reported that adding a buffer solution, such as sodium bicarbonate (NaHCO3) with magnesium oxide (MgO) increased dry matter intake when corn silage was the sole or major source of forage in the diet,” notes a 2022 study on increasing buffer capacity in cattle.
When an animal has acidosis, sodium bicarbonate is used because it provides a natural buffer. Although, it has high solubility which limits buffering against acidic conditions.
Proper usage across species
The use of products to support rumen health should always be done judiciously according to species and keeping in mind the end purpose of the animal – meat, milk or breeding.
For example, a 2020 study on growing Awassi lambs found adding certain buffering agents improved feed conversion, rumen pH and carcass quality while reducing body fat compared to a control diet. It was noteworthy that different products influenced meat colour, fat content and visceral fat percentages. Overall, these supplements enhanced animal performance, potentially optimising productivity and carcass attributes for meat-focused lamb operations.
Likewise, certain probiotic strains can influence animal health and productivity by supporting or disrupting rumen function, depending on the strain used and animal purpose.
One study examining microbial additives in ruminant diets found that probiotics aid in stabilising gut health, enhancing feed conversion, and potentially boosting immunity and nutrient absorption, while some strains may disrupt balance if misapplied.
Optimal animal health and productivity requires maintaining solid gut health when an animal is healthy and altering it when it is not. This often involves a balanced approach to probiotics, prebiotics, and rumen buffers.
By maintaining a stable rumen environment, producers can improve digestive efficiency and foster a resilient microbiome that contributes to sustained health and high performance in ruminants. Carefully managed gut health strategies not only enhance the welfare of the animals but also ensure consistent productivity, benefiting livestock and producers alike.
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