Nutraceuticals: an alternative to antibiotics for calves?

Emerging antibiotic resistance, along with multidrug-resistant zoonotic bacterial strains, has led to changes in livestock HEALTH decisions and the search for alternatives. What do the experts say?

“We hear a lot these days about supporting our own health with substances like essential oils and probiotics. Are these alternatives to traditional pharmaceuticals beneficial for calves? – Maureen Hanson writes in an article published on www.dairyherd.com. - According to veterinary researchers at Texas Tech University Michael Ballou and Emily Davis, it is still difficult to give a definite answer.

Ballou and Davis shared research findings on several classes of nutraceuticals used to support health, performance and/or immunity in dairy animals. There is growing interest in this class of drugs from veterinarians and animal breeders as they look for alternatives to antibiotics.

The experts explained that in order to be classified as a "nutraceutical", an oral supplement must improve some aspect of animal health or performance.

Depending on the substance, this improvement may be due to the stabilization of microbial communities; increased immunity by improving the reaction of the mucous membrane and barrier functions; harm reduction from potential pathogens or toxins; improved antioxidant status; direct antimicrobial action; increase or decrease in the systemic response of leukocytes.

Although it sounds promising, Ballou and Davis warned that the field of nutraceuticals is somewhat uncharted territory in veterinary medicine. For example, unlike veterinary drugs such as antibiotics, nutraceuticals are not regulated by the US Food and Drug Administration (FDA). As such, their claims regarding composition, dosage, efficacy, and quality are not independently verified, and manufacturers cannot legally claim efficacy against specific diseases or organisms.

However, this does not mean that the drugs do not work. Texas Institute of Technology researchers have detailed three classes of nutraceuticals and provided evidence for their benefits to calves, including:

prebiotics (biologically modifying polysaccharides) - these non-digestible carbohydrates are delivered to promote the growth of beneficial bacteria. They have been shown to improve immunity, bind harmful bacteria, and adsorb harmful substances such as mycotoxins. Two prebiotics commonly used in calves are mannan-oligosaccharides (MOS) and beta-glucans (BG). Both products are fungal (yeast) cell wall fractions. Scientists have found that MOS are effective in curbing exposure to Gram-negative bacteria such as Salmonella and E. coli in calves. BG enhance both systemic immunity and local immunity in the digestive tract. Probiotics (Direct-Acting Microorganisms) - These live microorganisms are delivered to improve microbial communities and cellular function in the gastrointestinal tract. Common commercially available animal products include Lactobacillus species and other lactic acid producing bacteria; types of bifidobacteria; bacillus species and Saccharomyces cerevisiae. As the calf's digestive system develops rapidly, the increase in lactic acid producing bacteria helps to repopulate the gut with "good" bacteria and crowd out "bad" bacteria such as Enterobacteriaceae. Probiotics also support immunity and reduce inflammatory reactions in the gastrointestinal tract of calves. Phytonutrients. This broad group of compounds are extracted from plants to provide antioxidant, anti-inflammatory and/or antimicrobial properties. Essential oils are classified as phytonutrients, as are concentrated plant extracts. A study of dairy calves treated with pomegranate extract, showed a positive immune response. In another study, administration of oregano oil to dairy calves before weaning reduced the incidence of diarrhea and improved blood biochemistry.

Experts have warned that many uncertainties remain regarding nutraceuticals because it is a booming field without much oversight from regulators. Products can vary greatly in composition, quality and concentration, and many contain mixtures of several substances. Bottom line: When choosing nutraceuticals, rely on product-specific data and seek advice from trusted advisors such as your veterinarian and/or calf nutritionist.”