Timothy grass (Phleum pratense) is a highly valued, cool-season forage grass cultivated globally for its exceptional quality as hay. It is favored for feeding horses, rabbits, and other small herbivores due to its soft texture and generally lower sugar content. The longevity of Timothy grass is divided into two distinct parts: the lifespan of the plant in the field and the nutritional viability of the harvested hay. Understanding this dual longevity is key to managing both the pasture and the feed supply.
Understanding the Dual Lifespan of Timothy Grass
The Timothy grass plant is a perennial, meaning established stands can persist and regrow for multiple years in the field. While the stand is long-lived, individual shoots have a shorter lifecycle, typically lasting through parts of two growing seasons. New shoots develop annually from the base, creating a continuous, perennial presence, particularly in cool, moist regions.
The lifespan of Timothy hay is defined by its quality and safety after being cut, dried, and baled. When properly harvested and stored, high-quality Timothy hay is considered safe and nutritionally sound for up to three years. However, natural degradation begins immediately following harvest, meaning the hay does not remain at its peak nutritional value for that entire duration. Experts agree that hay should ideally be used within one to two years to ensure maximum palatability and nutrient retention.
Factors That Determine Hay Degradation
The primary cause of hay spoilage is excessive moisture, which creates an environment where mold and fungi can flourish. Baling hay with a moisture content above 20% increases the risk of mold growth, which produces harmful mycotoxins. Moldy hay often presents as dusty, sometimes with visible white or gray patches, and carries a distinct musty odor, making it potentially toxic for animals.
Another factor affecting hay quality is the loss of color, indicating nutritional decline due to environmental exposure. The bright green color of fresh hay fades to yellow or brown when exposed to sunlight, signifying the destruction of Beta-Carotene. Beta-Carotene is a precursor to Vitamin A, and this loss can decrease by about 10% per month with direct sun exposure. While overall protein and energy content remain stable, the loss of this light-sensitive vitamin necessitates supplementation for animals fed older hay.
Physical degradation also reduces lifespan by affecting palatability and safety. Hay that becomes brittle from excessive drying is prone to leaf shatter, reducing feed value since leaves hold higher nutrient concentrations. Handling and storage can introduce dust or soil contamination, posing a respiratory hazard for livestock. Rodent and insect damage can also compromise bale integrity and contaminate the hay with feces and urine, rendering it unsafe for consumption.
Essential Storage Practices for Maximum Shelf Life
The most critical step in maximizing the hay’s shelf life is rigorous moisture control, starting at baling. Timothy grass must be fully cured to a moisture content of 20% or less for small square bales. For larger, denser bales, the moisture level should be lower, ideally between 12% and 16%, to mitigate internal heating. When microbial respiration occurs in bales that are too wet, the resulting heat can reach dangerous levels, potentially leading to spontaneous combustion at 140°F or higher.
Proper storage location and technique are equally important to prevent moisture re-entry. Hay should be stored in a well-ventilated barn or shed to shield it from rain, snow, and direct sunlight. Bales must be elevated off the ground, typically on pallets, to prevent moisture wicking from the soil or floor. Storing bales directly on the ground can lead to significant dry matter loss, sometimes affecting up to 50% of the bottom layer.
The arrangement of bales should prioritize airflow and ventilation. Stacking bales with small spaces between rows allows for air circulation, which helps dissipate residual heat and prevents condensation. Protecting the hay from pests like rodents is also necessary to prevent contamination and waste. Monitoring temperature and ensuring a dry, stable environment are the most effective ways to maintain the hay’s quality and safety over extended periods.