The question of whether Timothy grass and Timothy hay are the same is a common point of confusion, particularly for those responsible for feeding livestock and small pets. While they originate from the identical plant, Phleum pratense, the two products are fundamentally different in their physical state and nutritional composition. Timothy hay is the processed, preserved form of Timothy grass, created through agricultural intervention. Understanding the difference between the living plant and its cured form is necessary for proper use in animal diets.
Timothy Grass The Living Plant
Timothy grass (Phleum pratense) is a hardy, cool-season perennial grass cultivated extensively as a forage crop across temperate regions. It is characterized by tall, erect stems, often reaching heights of 20 to 120 centimeters. The plant is easily identifiable by its dense, cylindrical flower or seed head, which is spike-like in appearance and waves distinctively in the breeze during the summer months.
The grass grows in clumps and possesses a shallow, fibrous root system. The lowermost internodes often swell to form bulblike structures called corms, which serve as storage organs for carbohydrate reserves, helping the plant survive colder conditions. When harvested in its living state, Timothy grass is extremely high in moisture, typically containing 60 to 80 percent water by weight. This high moisture content contributes to a nutrient profile that is unstable and prone to rapid degradation once cut.
The Transformation From Grass to Hay
The distinction between grass and hay begins when the Timothy plant is cut, initiating a process designed to halt biological activity and reduce moisture content. Farmers typically harvest the grass at the late vegetative or early bloom stage, just as the seed heads emerge, to balance yield and nutritional quality. Harvesting too early reduces yield, while harvesting too late results in a less palatable, overly stemmy product.
After cutting, the grass is left in the field to undergo a process called field curing, where it dries under the sun and wind for several days. The goal is to reduce the moisture level from the original 60–80 percent down to a stable range of approximately 10 to 15 percent. This significant moisture reduction is necessary to inhibit the growth of spoilage organisms, such as molds and bacteria, and to prevent spontaneous combustion during storage. Once the material is sufficiently dry, it is then compressed and bound into bales for long-term storage and distribution as Timothy hay.
Nutritional and Practical Differences
The drying process results in substantial changes to the grass’s nutritional makeup, creating the practical differences between hay and grass. Fresh Timothy grass can have relatively higher concentrations of simple sugars and protein compared to hay, especially when the plant is young. However, the high moisture content of the living plant makes it difficult to feed in large, consistent quantities without causing digestive upset in many grazing animals.
Timothy hay is prized as an ideal feed for adult herbivores because the curing process concentrates the structural carbohydrates. This results in a higher concentration of structural fiber, measured by Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF), which is essential for maintaining healthy gut motility and wearing down continually growing teeth. The lower moisture and sugar content in hay makes it a safer, more consistent, and lower-energy feed source, contrasting sharply with the variable, high-moisture profile of the living grass.