Probiotics in Cattle: What Research Says About Milk Production, Immunity and Calf Health

Probiotics are increasingly studied as feed supplements that may support cattle health and productivity without relying on conventional antibiotic growth promoters. In cattle, these preparations commonly contain beneficial bacteria, yeasts or fungi, including species of Lactobacillus, Enterococcus, Bacillus, Saccharomyces and Aspergillus.

Research suggests that probiotics may influence more than digestion. Their effects can extend to milk production, milk composition, immune activity and calf development. However, the outcome depends strongly on the microorganisms used, dosage, formulation and condition of the animals.

Probiotics in cattle

How do probiotics work in cattle?

The digestive tract of cattle contains a complex microbial population that helps break down feed and make nutrients available to the animal. Probiotic supplementation is intended to support this microbial ecosystem.

The benefits includes:

• Stabilize microbial populations in the digestive tract

• Increase digestive enzyme activity

• Improve feed digestion and nutrient utilisation

• Restrict the growth of potentially harmful microorganisms

• Support the development of the digestive system in calves

  
  

For probiotic microorganisms to remain effective, they must tolerate acidic conditions, resist bile acids, survive storage and digestive conditions, and temporarily or permanently associate with the intestinal surface.

Effects on milk production

A study conducted on 16 lactating crossbred cows examined a multi-strain probiotic containing Lactobacillus acidophilus, Saccharomyces cerevisiae, Saccharomyces boulardii and Propionibacterium freudenreichii. The cows were divided into four groups receiving either no probiotic or 10, 15 or 20 grams per animal per day.

During the experimental period, the probiotic-supplemented groups produced approximately 8%, 10% and 21.36% more milk per week than the control group, corresponding to the 10-, 15- and 20-gram supplementation levels.

The response was not immediate or uniform throughout the trial. Improvements began to appear during the first week of supplementation, while a more noticeable increase was observed from the fourth week onwards. This suggests that probiotics may require consistent administration before their effects become clearly measurable.

Can probiotics improve milk composition?

The same study also examined milk fat, protein and solids-not-fat, or SNF.

During the supplementation period, average milk fat increased from 3.42% to about 4.15% in some groups.  SNF increased from 8.82% to 8.85%. However, they also noted that the economic value of supplementation would depend on probiotic cost and the existing milk production level of the cows.

A review of other cattle studies shows that these responses are not universal. One probiotic containing Prevotella bryantii increased milk fat from 3.5% to 3.9% but did not increase milk yield. Another preparation containing Lactobacillus casei and dextran improved milk production during summer but not during winter. The latter was also associated with lower somatic cell counts and fewer cases of mastitis in the evaluated cows.

These differences demonstrate why probiotic products should not be considered interchangeable. Strain composition, accompanying ingredients and environmental conditions can influence the result.

Probiotics may also influence immunity

The effects of probiotics are not limited to the rumen or intestine. A study involving ten mid-lactation Holstein-Friesian cows investigated whether oral probiotic supplementation could produce systemic changes.

Five cows received a commercial multi-strain probiotic daily for 60 days, while five cows served as untreated controls. The formulation contained Lactobacillus acidophilus, Saccharomyces cerevisiae, Enterococcus faecium, Aspergillus oryzae and Bacillus subtilis.

Probiotic supplementation did not significantly alter body weight, packed cell volume or plasma protein concentration. However, the percentage of lymphocytes increased, while the percentage of neutrophils decreased in the supplemented cows.

Gene-expression analysis identified 10,859 genes whose expression differed after supplementation, including 1,168 upregulated and 9,691 downregulated genes. The researchers identified 87 affected biological pathways, including pathways related to:

• Toll-like receptor signalling

• Inflammatory responses

• Cytokine and chemokine activity

• Wnt signalling

• NF-κB and MAPK signalling

• Innate and adaptive immunity

• Cellular homeostasis

  
  

The findings indicate that orally administered probiotics can influence immune-related activity throughout the animal rather than acting exclusively within the digestive tract. Nevertheless, changes in blood cells and gene expression do not by themselves prove that the animals will experience fewer infections or diseases. Larger studies measuring clinical outcomes would be required to establish that connection.

Potential benefits for calves

Young calves may benefit from probiotics because their digestive systems and microbial populations are still developing. Reports suggest that that probiotic supplementation can support stomach development, digestive health, disease resistance and weight gain.

In a study, calves received a multi-organism probiotic containing Lactobacillus, Bifidobacterium bifidum, Enterococcus faecium, Streptococcus thermophilus, Aspergillus oryzae and a yeast strain. After 90 days, supplemented calves had a final weight gain seven kilograms higher than the control calves. They also showed greater resistance to disease, particularly diarrhoea.

These findings suggest that probiotics may be particularly relevant during periods when calves face nutritional, environmental or digestive stress.

Choosing an effective probiotic

Probiotic preparations may contain a single microorganism, several bacterial strains, yeast, fungal extracts or combinations of these components.

However, some preparations may be degraded in the rumen of adult cattle. Suitable protection or formulation may therefore be necessary for the microorganisms to reach their intended site of action.

When evaluating a cattle probiotic, the most important questions are:

• Which microorganisms and strains does it contain?

• What quantity of each organism is provided?

• Has that formulation been tested in the intended animal group?

• Is the objective higher milk yield, improved milk composition, immune support or calf growth?

• Can the organisms survive storage and passage through the digestive tract?

• Does the value of the production response justify the supplementation cost?

Conclusion

Studies show probiotics as promising nutritional tools for cattle. In lactating cows, selected multi-strain preparations increased milk production and produced smaller improvements in milk fat, protein and SNF. In another study, probiotic supplementation influenced lymphocyte and neutrophil proportions and altered the expression of genes involved in immunity and homeostasis. Evidence reviewed in calves also indicates potential improvements in growth and resistance to digestive disease.

At the same time, probiotic responses vary considerably between formulations and production conditions. The benefits observed with one combination, dose or animal group cannot automatically be applied to every probiotic product. Effective use therefore requires strain-specific evidence, appropriate formulation, consistent administration and an economic assessment under actual farm conditions.

Sources

[1] Vibhute, V. M., Shelke, R. R., Chavan, S. D., & Nage, S. P. (2011). Effect of Probiotics Supplementation on the Performance of Lactating Crossbred Cows. Veterinary World, 4(12), 557–561.

[2] Adjei-Fremah, S., Ekwemalor, K., Asiamah, E. K., Ismail, H., Ibrahim, S., & Worku, M. (2018). Effect of Probiotic Supplementation on Growth and Global Gene Expression in Dairy Cows. Journal of Applied Animal Research, 46(1), 257–263.

[3] Radzikowski, D. (2017). Effect of Probiotics, Prebiotics and Synbiotics on the Productivity and Health of Dairy Cows and Calves. World Scientific News, 78, 193–198.