Researchers in Canada, the UK, and China have been examining the use of dried yeasts within grain-fed cattle’s diets and it’s believed to improve intestinal digestion. The study was published in Animal Feed Science and Technology and reviewed the use of encapsulated and non-encapsulated dry yeast. The study aimed to measure feed intake, fermentation, and ruminal pH and to see how active dry yeast performs as a probiotic compared to current options.
The research stated that feed additives did not impact the feed intake or ruminal digestibility of the feed. However, post-ruminal digestion of neutral detergent fiber and organic matter was greatly improved with encapsulated yeast or a combination of non-encapsulated and encapsulated yeasts. It was believed that the improvement to organic matter digestion was primarily due to the neutral detergent fiber digestion improvement. The results of the study showed that it helped to improve the digestibility of nutrients within the feed.
Why Are Yeast Supplements Being Researched for Cattle?
In North America, adding antimicrobial ingredients to feed has been a common practice for many years. The aim was to promote growth. At the current time, monensin is often used for this purpose, which is an ionophore. Farmers and researchers have often criticized feeding antibiotics to cattle, as it can increase their antimicrobial resistance. Therefore, finding a good value alternative that still offers the same quality as antibiotics do, is constantly being researched. Probiotics, such as yeast or bacteria, are safe to add to cattle feed. It can help to improve the overall health of the animal and the efficiency of production.
While more research has been undertaken in the past on dairy cows, beef cattle production is now gaining further interest from researchers. Previous studies show that probiotic yeasts can help increase milk production or feed efficiency when given to dairy cows. Yeast helps to stimulate lactate-utilizing bacteria and cellulolytic, which can stabilize the ruminal pH levels. Beef cattle showed mixed results in similar studies. But this could also be due to their diet and the yeast strain being used.
Most research into probiotic yeasts looked at rumen fermentation and stabilizing the rumen pH. This helps to encourage lactate-using bacteria to grow. It can also improve oxygen collection, fiber digestion, and the growth of ruminal protozoa, with a few other benefits also being found during the research. However, at the moment, very little research has been done into how the live yeast may impact the beef cattle after the rumen. Researchers are now looking into ways to protect live yeast so it can travel to the lower gut.
The Materials and Methods Used in Studies
During the study we referenced above, a 21-day period was used for five castrated beef cattle. They were all given one of five different diets, and then after three weeks, they rotated to another of the five diets. Each time they switched diets; they have one week to adapt to the changes. The five diets consisted of a control diet, one with monensin and tylosin, one with active dry yeast, one with encapsulated active dried yeast, and finally, a mixed diet. To encapsulate active dried yeast, a barley hordein and glutelin were used, and the study also looked at how stable this was within the rumen.
The cattle were all fed a mixed feed. This feed included corn dried distillers’ grain, barley silage, barley grain, and supplements including vitamins and minerals they need. When feed was offered and refused was recorded each day and samples were collected each week during the study. The cattle were weighed at the beginning and end of each diet they were on. Whereas a few days towards the end of the study rumen content and omasal samples were taken. Key areas that were reviewed during this time were feed intake, the flow to the omasum, the digestibility of the feed in the intestine, and the ruminal pH.
After the research was completed, it was concluded that the intake of dry matter wasn’t affected by any of the five diets. Moreover, the ruminal pH, ammonia levels, and volatile fatty acids were the same for all of the diets. None of the diets impacted the flow of matter or the amount of starch within the omasum. Neutral detergent fiber flow was highest with monensin and tylosin but lowest with encapsulated active dried yeast.
When yeast was added as a probiotic to the diet, the molar proportion of acetate and the ratio of acetate were higher. Digestion of organic matter in the rumen was also lowest when the cattle were fed encapsulated or mixed yeast diets. However, it was shown that post-ruminal digestion improved with either of these diets. The digestibility of organic matter and neutral detergent fiber in the digestive tract was also improved. The research concluded that feeding protected yeast to cattle can help to increase intestinal digestibility of nutrients. No changes were found to the flow of nitrogen.
This was certainly one of the most exciting studies for the development of cattle feed. It offers a new alternative for farmers and suppliers around the world. While more research is likely to be needed in the future into this area, we can only hope it will help to reduce the use of antibiotics and offer an improved feeding experience for cattle and their farmers.