Nutraceuticals: An Alternative to Antibiotics for Calves?
Updated: Apr 5, 2022
February 9, 2022
We hear a lot about supporting our own health with substances like essential oils and probiotics these days. Do these alternatives to traditional pharmaceuticals have beneficial effects in calves, too?
Maybe, according to Texas Tech University veterinary researchers Michael Ballou and Emily Davis. But also, maybe not.
At the 2021 Western Canadian Dairy Seminar, Ballou and Davis shared research results from several classes of nutraceuticals used to support health, performance, and/or immunity in dairy animals.
They said interest in this class of health support tools on the part of veterinarians and producers is growing, as they seek alternatives to antibiotics.
The researchers explained that, in order to be classified a “nutraceutical,” an oral supplement must improve some aspect of animal health or production.
Depending on the substance, this improvement may come about by stabilizing microbial communities; boosting immunity by improving mucosal response and barrier functions; adsorbing potential pathogens or toxins; improving antioxidant status; direct antimicrobial activity; or either increasing or decreasing systemic leukocyte (white blood cell) response.
While all of those actions sound promising, Ballou and Davis cautioned that the nutraceutical field also is somewhat unchartered territory in veterinary medicine. Unlike veterinary drugs like antibiotics, nutraceuticals are not regulated by the U.S. Food and Drug Administration (FDA).
Thus, their statements regarding composition, dosage, effectiveness, and quality are not independently validated, and they cannot legally make claims of efficacy against specific diseases or organisms.
That’s not to say they don’t work, though. The Texas Tech researchers detailed three classes of nutraceuticals, and provided evidence of their benefits to calves, including:
Prebiotics (biological modifying polysaccharides) – These indigestible carbohydrates are delivered to boost the growth of beneficial bacteria. They have been shown to improve immunity, bind harmful bacteria, and adsorb harmful substances like mycotoxins. Two prebiotics commonly used in calves are mannan-oligosaccharides (MOS) and beta-glucans (BG). Both products are fractions of cell walls from fungi (yeast). Researchers have found that MOS is effective in deterring the effects of Gram-negative bacteria like salmonella and E. coli in calves. BG has been shown to enhance both systemic immunity, and localize immunity in the digestive tract.
Probiotics (direct-fed microbials) – These living micro-organisms are delivered to enhance microbial communities and cellular function in the gastro-intestinal tract. Common, commercially available products for livestock include Lactobacillus species and other lactic-acid producing bacteria; Bifidobacterium species; Bacillus species; and Saccharomyces cerevisiae. Because calves’ digestive systems are rapidly developing, boosting lactic acid-producing bacteria has been shown to help populate the gut with “good” bacteria and crowd out “bad” bacteria like Enterobacteriaceae. Probiotics also have been shown to support immunity and reduce inflammatory responses in the gastrointestinal tract of calves.
Phytonutrients – This broad group of compounds are extracted from plants, with the goal of capturing antioxidative, anti-inflammatory, and/or antimicrobial properties. Essential oils fall into the phytonutrient class, as do concentrated plant extracts. A study of dairy calves supplemented with pomegranate extract showed positive immune responses. Another study administering oregano oil to preweaned dairy calves reduced scours incidence; improved blood chemistry; and boosted immunoglobulins.
The Texas Tech researchers cautioned that there remains a lot of ambiguity regarding nutraceuticals because it is a rapidly evolving field without much regulatory oversight. Products can vary greatly in composition, quality, and concentration, and many of them contain blends of multiple substances.
This makes apples-to-apples comparisons among nutraceutical products difficult. The upshot: when choosing nutraceuticals, rely on data specific to the product, and seek the advice of trusted advisors like your veterinarian and/or nutritionist for counsel.