While whitetail deer might consume hay, it is not a suitable food source for them. Understanding their natural diet provides why hay can be detrimental to their health. Their digestive systems are adapted to process specific forage, differing significantly from hay.
Deer Digestive Biology and Natural Forage
Whitetail deer possess a four-chambered stomach, like other ruminants, enabling them to digest complex plant materials. The first and largest chamber, the rumen, acts as a fermentation vat where billions of microorganisms break down food. This microbial community, of bacteria and protozoa, extracts nutrients from fibrous foods deer naturally consume. Deer regularly regurgitate and re-chew their food, a process called rumination, further aiding digestion.
A whitetail deer’s natural diet consists of browse (woody plants), forbs (broad-leafed plants), and mast (nuts/fruits). Browse, such as twigs, leaves, and buds from trees and shrubs, forms a significant portion of their diet, particularly in winter when other foods are scarce. Forbs are highly digestible and nutrient-rich, while mast provides high-energy sources, especially in fall. The composition of their gut bacteria gradually adjusts seasonally to efficiently digest these varying natural food sources.
Risks of Hay for Deer Digestion
Hay, being dried grasses, presents digestive challenges for whitetail deer, especially in winter. Their rumen microbes are adapted to a high-fiber, woody diet in colder seasons, making hay problematic. Their digestive system’s inability to process hay can lead to severe health issues, even if consumed.
A rapid intake of unfamiliar carbohydrates in hay can lead to a condition called acidosis. This occurs when rapid fermentation in the rumen produces a large amount of lactic acid, causing a sudden drop in the stomach’s pH. Acidosis can disrupt the beneficial microbial balance, interfere with digestion and nutrient absorption, and may result in bloat, severe diarrhea, and even death within days. Hay often lacks the specific nutrients and fiber types deer need for proper metabolism, potentially leading to malnourishment even with a full stomach. Deer can starve with a stomach full of hay because their system cannot extract adequate nutrition.
Broader Implications of Supplemental Feeding
Beyond the direct digestive issues caused by hay, any form of supplemental feeding of wild deer carries broader negative consequences. Concentrating deer at feeding sites increases the risk of disease transmission among them. Diseases like Chronic Wasting Disease (CWD) and Bovine Tuberculosis (TB) can spread rapidly through direct contact or indirectly via contaminated feed and saliva left at these sites. CWD prions, for instance, can remain infectious in the environment for years.
Supplemental feeding can also lead to deer becoming dependent on artificial food sources, altering their natural foraging behaviors and instincts. This dependency can increase human-deer conflicts and make deer less wary of people, which can pose risks to both deer and humans. Unnatural congregation of deer can lead to increased aggression among individuals vying for food, further weakening them. Concentrated deer populations near feeding areas can overbrowse local vegetation, damaging natural habitat and disrupting the ecosystem. Many states and localities discourage or prohibit feeding wild deer to mitigate these risks.