Boosting Beef Profits with Live Yeast Supplementation.

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The world of probiotic feed additives is divided into three main categories—lactic acid bacteria, spore-forming bacteria and live yeasts. Yeast cells that are added to the diet that, when fed at an appropriate concentration, benefit the consumer.

In cattle, probiotic yeasts have been widely used to prevent digestive disorders and improve feed intake and efficiency. It is well known that live yeasts have a positive effect on the rumen microbiota and, thus rumen health and activity. This ultimately leads to better feed utilization and nutrient delivery, as well as overall health and performance.

Live yeasts aids in the digestion of ruminant feeds in several ways. Through its metabolic activity, live yeast reabsorbs oxygen from the rumen and promotes a more favorable environment for the development of microorganisms—primarily anaerobic cellulose-degrading and lactate-consuming bacteria—that maximize the rate of fiber breakdown, stabilize the ruminal pH and provide micronutrients for metabolic support (Figure 1), which in total reduce the risk of acidosis, positively influencing digestive capacities and wellbeing.

Figure 1: The mechanisms of action and benefits of live yeasts.

Live yeast should be dosed high enough to ensure an efficient and rapid effect. A minimum of 3x10¹⁰ CFU per day should be fed to fattening bulls. Probiotic dosages are expressed in CFU, meaning colony forming units, and is a measure of the number of viable or active yeast cells.

Beef production systems are designed to maximize growth and profitability in the face of high price pressures. The goal is to shorten fattening times and improve feed utilization while achieving the highest quality meat. This is linked to optimizing diets and ensuring rumen health, but also to feeding high-concentrate diets with low fiber. These energy-rich diets can lead to digestive disorders such as ruminal acidosis.

Live yeasts can be particularly helpful for fattening bulls. They are known to have a positive effect on ruminal microbial activity by stabilizing pH and by improving digestive capacities for better feed efficiency, especially in cattle on high-concentrate diets that alter the microbial ecosystem, which is also a big stress factor for the bulls. Live yeasts can help to reduce this stressor by improving microbial population in the rumen. The supplementing of live yeasts in fattening cattle has resulted in:

The effects of Biosprint® live yeast supplementation on zootechnical performance and carcass quality were evaluated in a field trial with 63 crossbred fattening bulls during their starter and finisher periods. Animals were assigned to either a control group or a 2 g/head/day live yeast supplemented Biosprint® group. Daily weight gain (DWG) and feed conversion ratio (FCR) were calculated from body weight and feed intake measurements. Fecal digestibility was assessed by a sieve washing performed twice per feeding group at the end of fattening.

Supplemented animals had an improved DWG by 3.4 % in the starter and by 2.5 % in the total phase compared to control animals. Similarly, FCR was improved by 3.1 % in the starter and by 0.74 % in the total phase in supplemented animals (Figure 2). These results underscore the benefits of supporting rumen health early in life, even when the rumen is still developing or under increased stress.

Figure 2: Biosprint® improved DWG and FCR in the starter period by 3.4 % and 3.1% respectively. Biosprint® supplementation, especially in the starter phase, led to a support of ruminal health and subsequent performance.

Manure washing provides an indication of the degree of digestion. Manure is “washed” through three successive screens of different sizes. This separates and collects all the particles in the manure by size. Ideally, the > 50 % of the particles would be collected on the bottom (smallest) screen. The presence of large particles on the top (largest) screen may indicate improper rumination or a too fast rumen passage rate.

Manure washing results show that bulls supplemented with live yeast (Biosprint®) had more residue in the smallest particle size distribution and significantly less feces, with a coarse particle size distribution collected in the top screen (Figure 3; P = 0.008). Since smaller particles in the feces point to better digestive ability to break down fiber, these results indicate improved rumen health and digestive capacity.

Figure 3: The results of manure washing. More fine and less coarse particles are seen in the feces from bulls supplemented with Biosprint® compared to control bulls.

The groups supplemented with live yeast received numerically better carcass scores than the control groups, with all carcasses graded in the higher quality categories. Optimized feeding and nutrient supply are critical for good carcass quality. Therefore, supplementation with Biosprint® resulted in a positive return on investment due to improved carcass scores and increased carcass weights.

Biosprint® live yeast has been shown to support fattening bulls by improving rumen health and functionality. This positive effect was seen in improved DWG and FCR, and better digestibility. Ultimately, this digestive support resulted in improved carcass quality and a positive return on investment.