The dairy industry and climate change - What role do live yeasts play?

In politics, in the news and in scientific communities, never before has climate change been discussed so intensely as a global environmental risk. Research is being conducted across all sectors to improve the climate situation. Within the scope of its possibilities, the agricultural industry also wants to support climate protection and is researching ways to minimize greenhouse gas emissions. But this is not the only problem: agriculture is also facing the challenges that accompany climate change. This is why it is important to find ways to reduce greenhouse gas emissions in agriculture and reduce the impact of climate change.

Live yeasts—single-cell microorganisms—in dairy cattle feed can help improve animal health and milk yield. As probiotics, live yeasts have a positive impact on the rumen microbiota of dairy cows and fattening bulls. They can also support the digestive processes in other animal species. Thanks to their metabolic activity, live yeasts are capable of reabsorbing oxygen and promoting an anaerobic environment in the rumen. One positive effect lies in increased growth of cellulolytic and lactate-consuming bacteria. This influence on the rumen microbiota results in a stabilization of the rumen pH and an improvement in feed digestibility, which ultimately leads to increased feed efficiency. The use of live yeast also increases the presence of beneficial rumen bacteria, which leads to increased gut microbial protein accumulation. It is important to keep in mind that the metabolic processes of live yeast produce valuable micronutrients that support the animal’s metabolic processes.

The generation of methane emissions in the dairy industry can be minimized by using live yeasts to increase the animals’ milk yield. In other words, the carbon footprint per liter of milk is reduced. Live yeast also helps improve animal health and increase useful life. This leads to a reduction in the replacement rate and improves the sustainability of the individual animal, which also minimizes methane emissions. At the same time, live yeast has a positive effect on feed digestibility and efficiency. This reduces feed requirements for the production of one liter of milk and, in turn, lowers greenhouse gas emissions resulting from feed production. Along with these indirect effects, it is believed that live yeast helps reduce methane production in the rumen. There is evidence in the literature that live yeasts stimulate acetate-forming bacteria in the rumen by utilizing metabolic hydrogen which is then no longer available for methanogenesis [Broucek, 2018; Chaucheyras et al., 1995; Elanthamil & Bandeswaran, 2017].

Figure 1: The effects of the live yeast Biosprint^® with a dosage of 3g/animal/day (4.5e10 CFU/animal/day) on milk yield (ECM = energy-corrected milk).

Figure 2: The effects of the live yeast Biosprint^®with a dosage of 3g/animal/day (4.5e10 CFU/animal/day) feed intake.

Figure 3: The effects of the live yeast Biosprint^® with a dosage of 3g/animal/day (4.5e10 CFU/animal/day) feed efficiency.

In a field trial, Biosprint^® live yeast was compared with a preceding control group without supplemental yeast. Biosprint^® was dosed according to the manufacturer’s recommendation. The trial showed that, with Biosprint^®, improvements on feed efficiency and milk yield can be achieved with a nearly identical feed intake compared to the control group (Fig. 1-3). Biosprint^® thus contributes to more sustainable milk production.

The change in climatic conditions has a significant impact on dairy cattle farming in many different ways. Targeted measures are necessary to minimize the effects and to safeguard animal welfare and performance. Increasingly longer periods of unusually high summer temperatures, which can quickly lead to heat stress in dairy cows, is one of the direct effects of climate change on dairy farming. Combined with high relative humidity (>70%), ambient temperatures above 21-24°C can cause heat stress in cows. High metabolic activity, especially in lactating animals, also significantly increases body heat. This can result in reduced feed intake, quantitative and qualitative milk yield losses, increased cell counts, rumen over-acidification, fertility problems, or immune system impairments. Lying and ruminating behaviors are also affected – indicators that the animal feels unwell.

Extreme weather conditions, such as drought and heavy rainfall, increase the risk of poorer forage harvests in terms of quantity and quality. This includes, for example, poorly digestible forage crops with an increased fiber or lignin content. Climatic changes also lead to an increase in certain weeds and problems caused by pests. These can trigger disorders in both animals and plants and lead to yield losses. Poor forage quality reduces digestibility and makes it difficult to provide adequate nutrients to animals. One indirect effect is the economic impact. For example, deteriorating climatic conditions in key growing regions can increase the cost of purchased feed.

In addition to increasing air circulation with ventilator fans or spraying water to cool animals down, feed technology aids such as salt licks or live yeasts can alleviate the effects of heat stress in cows. Heat stress can quickly lead to a risk of acidosis in dairy cows due to reduced rumen buffering. Therefore, it can be assumed that live yeasts provide a mitigating effect by stabilizing rumen pH. Live yeast also helps stimulate feed intake, which decreases during heat stress and often leads to lower milk yields. This can trigger ruminating behavior, which is important for buffering the rumen environment. Inferior forage quality resulting from climate change can be offset with live yeast to improve fiber digestibility and feed efficiency. Figure 4 illustrates the result of a study in which Biosprint^® live yeast was tested at a dosage of 4g/Animal/Day (6x10¹⁰CFU /animal/day) compared to a control group during heat stress (THI=79). The significantly positive effect of Biosprint^® live yeast on fiber digestibility can be seen here (P<0.05).

Figure 4: NDF (neutral detergent fiber) digestibility of cows receiving live yeast supplementation (Biosprint^®) compared to a control group during heat stress, *P<0.05, Dehghan-Banadaky et al., 2012.

The impact of climate change on milk production is complex. On one hand, the dairy industry is tasked with supporting a more sustainable approach to conducting business. On the other, methods must be developed to minimize the effects of climate change. Biosprint^® live yeast can help reduce greenhouse gas emissions by increasing rumen efficiency and health. At the same time, it can help mitigate the consequences and maximize production potential.

BROUCEK (2018): Options to methane production abatement in ruminants: A review, The Journal of Animal & Plant Sciences, 28(2): 2018, Page: 348-364 ISSN: 1018-7081

CHAUCHEYRAS, G. FONTY, G. BERTIN, P. GOUET (1995): In Vitro H₂ Utilization by a Ruminal Acetogenic Bacterium Cultivated Alone or in Association with an Archaea Methanogen Is Stimulated by a Probiotic Strain of Saccharomyces cerevisiae, applied and environmental microbiology, Sept. 1995, p. 3466–3467, Vol. 61, No. 9

ELANTHAMIL, C. BANDESWARAN (2017): Methane emission from ruminants and its mitigating measures using probiotic – A review, International Journal of Science, Environment and Technology, Vol. 6, No 1, 2017, 319–325