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11/02/2025
The Downsides of Alfalfa
Feeding 100% alfalfa as a forage program presents several issues that can be problematic for some horses.
Issue 1: Excess protein intake. When a horse consumes significantly more protein than required the extra protein must be excreted via the urine. Along with the protein being excreted, water and electrolytes are also excreted. This can result in poor stamina, predisposition to dehydration, and reduced heat tolerance (especially in hot and humid conditions).
Issue 2: Alfalfa may also have negative implications in horses that suffer from Exercise Induced Pulmonary Hemorrhage (commonly termed “bleeders”). Here’s why—if the diet contributes more protein than the horse requires, the excess is broken down into urea and excreted in the urine (this is evident by the ammonia smell). Ammonia fumes inhaled repeatedly over time can cause irritation in the airway which may cause the horse to bleed when exercised at high intensity. **Note: the root cause is excess protein in the diet, not alfalfa itself. Excess protein can also come from unnecessary amounts of grain and supplements.
Issue 3: A 100% alfalfa diet alters intestinal pH in a manner that can predispose the horse to enteroliths.
Issue 4: Excess calories. While typically low in sugar, alfalfa can be calorie dense, and if fed at high rates or to easy keepers, can oversupply calories. Obesity is an epidemic, and can lead to a long list of health issues.
My general recommendation for alfalfa intake for most performance horses (this includes breeding and growing)- ~50% or less of total daily forage. (Total forage includes grass). Generally 0% for maintenance horses.
I am not saying alfalfa is bad. It’s an excellent component of a proper, balanced diet. I am also not saying that horses shouldn’t eat alfalfa, rather it’s not the best option (and definitely not necessary) for every horse because of the reasons mentioned above.