Treats for Horses: Pay Attention to Packaging

“Paper or plastic?” While it’s not a question that might be asked frequently at grocery checkouts anymore, it is a query that occurred to researchers recently, at least those interested in the shelf life and palatability of horse treats.

At the end of a yearlong study, plastic packaging, specifically polyethylene, reigned supreme in this trial. How did researchers come to this conclusion?

For this study, the researchers used a single type of treat, described as an apple-flavored baked treat made from wheat flour, sugar, apples, honey, vegetable oil, natural flavor and color, preservatives (mixed tocopherols and citric acid), and rosemary extract. Treats were subjected to one of three storage methods: solid-sheet polyethylene bags stored at -80° C (-112° F) to inhibit natural degradation (control); polyethylene bags at ambient temperature (~21° C or 70° F , 45% relative humidity); or single-ply paper bags at ambient temperature (~21° C or 70° F, 45% relative humidity).

Treats were then evaluated at five time points during the year in their respective environment: 0 months (as received from the manufacturer); at 3 months; at 6 months; at 9 months; and at 12 months. At each time point, samples were evaluated for moisture content, water activity, mold, yeast, pH, and volatile organic acid content. Organic acids, such as acetic acid, butyric acid, and propionic acid, are formed in feed as a result of the metabolism of large molecular mass compounds and can play a role in the taste and aroma of feed products.

Palatability was also tested at this time using a standard preference test. Researchers noted which treat horses sniffed first, consumed first, and finished to completion first.

What specifically did the researchers learn from this study? According to them, “moisture content and water activity increased in all treatments from month 0 to month 12, with paper packaging providing a greater fluctuation and containing visible mold at month 12.”

As far as palatability, consumption of paper-packaged treats tended to decrease with time as consumption of poly-packaged treats increased over time. Although mold was not noticed on paper-packaged treats until treats had been in storage for a year, horses may have perceived a difference given their acute sense of smell.

In practical situations, treats sold in plastic packaging (polyethylene, polypropylene, different compositions of vinyl) should be stored in their original bags or containers and fed before their expiration date. Like other perishables, unused portions should be sealed tightly until the next use.

When treats are purchased in bulk, it might be tempting to ferry smaller portions to the barn in paper bags and stash them in a tack cubby or trunk. If the treats are consumed quickly, this is likely not an issue. But horse owners might want to think twice before storing horse treats in paper bags for months at a time, especially through changing seasons and humidity fluctuations. While buying in bulk has cost savings, it may not always be the best strategy for maintaining freshness and reducing waste.

“Like feed, supplements, and medications, always keep track of expiration dates of treats,” said Catherine Whitehouse, M.S., a nutrition advisor at Kentucky Equine Research. “This is especially true for treats that are no longer in their original packaging. When in doubt of a treat’s wholesomeness, throw it out, as all horsemen know too well the sensitive nature of the horse’s gastrointestinal tract.”

This study investigated the storage effects and palatability of one specific treat, not a wide range of products, so this should be considered when interpreting the results, Whitehouse pointed out. “The paper bags used in this study had no lining, which can reduce oil absorption and decrease permeability. High-quality feed bags are often lined with biopolymers that extend shelf life and keep feed wholesome.”

The nutritional content and quantity of treats offered should be considered as part of the total diet, particularly for horses suffering from metabolic disease, Whitehouse explained.

^*Francis, J.M., and E.B. Perry. 2021. The influence of packaging on palatability and shelf life stability of horse treats. Journal of Equine Veterinary Science 98:103326.