Alfalfa is known as the “queen of forages,” a title earned because of its high nutritional value, with elevated levels of protein, vitamins and minerals, as well as excellent palatability and digestibility. It is also one of the few crops that shows strong resilience under challenging growing conditions. It is no coincidence that, according to 2025 data from the USDA National Agricultural Statistics Service (NASS), alfalfa production in Idaho reached 4,190,000 tons on a dry matter basis, representing 960,000 harvested acres. This volume plays a key role in supporting the over 650,000 dairy cows responsible for the state milk production. Of this total, 3.5 million tons were used for hay production and 1.26 million tons for silage, highlighting its critical importance in dairy cattle nutrition in Idaho.
Climate challenges
Despite its productive relevance, climate has a major influence on maintaining feed quality, especially during the ensiling process. Lower average temperatures negatively affect fermentation, a crucial stage, causing significant delays in pH decline. In addition, annual losses due to winterkill can reach as high as 78%. In cold climates, these challenges intensify. Growing seasons are short and winters are long and severe, increasing reliance on conserved forages and requiring efficient harvest, storage and preservation systems. In these environments, silage becomes the foundation of dairy cattle diets, making its quality even more critical.
Cold nights and frequent frosts reduce plant metabolic activity. Early frosts decrease the population of lactic acid bacteria (LAB), which are essential for proper fermentation and favor the growth of spoilage yeasts and molds. At the same time, lower average daily temperatures can slow and reduce fermentation efficiency. Daily temperature fluctuations between day and night further complicate the situation by prolonging wilting and reducing carbohydrate, lipid and protein content in the forage.
Structural challenges add to these climatic factors. In cold regions, major difficulties are associated with storing and feeding alfalfa, whether as silage or haylage. During harvest, low temperatures and reduced solar radiation hinder proper drying, increasing the risk of ensiling forage at inadequate dry matter levels. As a result, fermentation may be compromised, undesirable microorganisms may proliferate and spoilage losses may increase. During storage, repeated freezing and thawing cycles can damage silo structures or plastic-wrapped bales, allow oxygen infiltration and reduce aerobic stability after opening. At feedout, frozen material can make removal and mixing more difficult, reduce ration uniformity and negatively affect intake. Daily temperature variations may also cause condensation inside plastic coverings, creating favorable conditions for yeast and other spoilage organisms. Therefore, management in cold climates requires close attention to dry matter at harvest, proper packing and sealing, appropriate use of inoculants and careful logistical planning to minimize exposure to air and extreme temperature fluctuations. In this context, it is important to note that some additives may be less effective in cold environments, since many bacterial strains in commercial inoculants were selected under warmer conditions. Therefore, always consult a technician about the inoculants recommended for alfalfa silage production.
Production and management
Proper fertilizer and water management are also essential to protect alfalfa from drought and cold stress while improving productivity. In general terms, and as practical considerations, potassium helps regulate water loss and supports the production of sugars, proteins and other vital compounds. Phosphorus is fundamental for forming cellular components and energy-storing molecules. Applying potassium and phosphorus after the final fall cutting can help the plant to store carbohydrates in its roots, which are later used to sustain vital functions during winter. Water management is equally important, as excessive soil moisture in winter can lead to freezing and thawing cycles that lift roots out of the soil and increase the risk of winter injury. Good drainage and interseeding with grasses help reduce this risk.
Cut timing and frequency are also critical for ensuring strong production, forage quality and plant survival. Very frequent cuts or cuts made too late in the fall prevent the plant from replenishing root energy reserves, increasing the risk of winter damage. As a general guideline, many operations aim for roughly a 42-day interval between cuttings, which often results in about four harvests per year, with the last cut made around four to six weeks before the first frost. These numbers should be viewed as a starting point and adjusted according to local weather conditions and the condition of the stand. Time of day also influences forage quality. Because the plant accumulates sugars throughout the day, cutting in the late afternoon, especially on sunny days, results in higher energy value. Although some carbohydrates are lost overnight, the plant can continue photosynthesis for up to three hours the following morning, compensating for that loss, particularly if it is left spread out on the ground without being windrowed or excessively wilted, maintaining a photosynthetic rate similar to that of morning-cut or standing plants.
Beyond timing, management practices also play a key role. Faster drying reduces nutrient losses, and laying forage in wider swaths instead of narrow windrows can accelerate wilting and help maintain higher sugar levels. Although part of these carbohydrates is used during fermentation, higher levels at harvest increase silage quality potential and may support improved animal performance and milk production.
As another practical tip for alfalfa management, interseeding alfalfa with bermudagrass may be worth considering. The two species complement each other well: Alfalfa tends to perform better in cooler conditions, while bermudagrass thrives during warmer periods. This natural seasonal balance helps maintain more consistent forage growth throughout the year. Field evaluations have shown that this mixture can provide high yields and quality forage for hay or silage, often allowing for more harvests compared to bermudagrass grown alone. For operations seeking greater seasonal stability and additional cutting opportunities, interseeding alfalfa with bermudagrass can be a useful and practical cultivation approach.
Overall, producing and preserving alfalfa in cold climates requires technical planning and strategic decisions at every stage, from cutting to feedout. Low temperatures affect fermentation, stability and nutritional value, making proper management essential to reduce losses and maintain forage quality. Even under challenging climatic conditions, high productive performance can be achieved when well-founded practices are applied consistently.
