Azolla and Its Effect on Cows and Calves
By Saleh Kamal Al-Saleh, dairy farm and cheese factory owner, founder of Lebnara · Last updated:
Azolla is a protein-rich aquatic plant, but 93% of it is water. So its contribution to the ration stays small at normal amounts. It is a cheap and useful supplement for small farms, not a substitute for concentrate as it is sometimes promoted.
What is azolla?
A small aquatic fern that floats on the water surface, living with a type of blue-green bacteria that fixes nitrogen from the air. That is why it grows fast and doubles its mass every 3 to 5 days under suitable conditions, with almost no nitrogen fertiliser.
Nutritional value
The important calculation: 2 kg of fresh azolla gives about 0.12 kg of dry matter, containing only 25 to 30 grams of protein. That is roughly equal to 70 grams of soybean meal.
| Indicator | Approximate value |
|---|---|
| Dry matter | 5 – 7% of fresh weight |
| Crude protein | 20 – 25% of dry matter |
| Other features | Rich in calcium, iron and carotene, and contains lysine |
| Weak point | Contains tannins and fibre that lower digestibility slightly |
The effect on dairy cows
- Milk yield: trials in India recorded rises of 10 to 15% when adding 1.5 to 2 kg a day, but many were on low-yielding cows with poor rations to begin with, so the improvement came from filling an existing deficiency. In a balanced ration the expected effect is small.
- Milk quality: some trials recorded a slight improvement in fat and solids-not-fat, and the results are inconsistent.
- Savings: concentrate can be cut by a small percentage, provided the azolla is in sufficient and regular amounts.
The effect on calves
In weaned calves and beef calves, azolla can replace 10 to 15% of concentrate protein without a drop in growth. But the fresh amount needed is large, and drying and grinding it makes it easier to use.
How to grow it, briefly
- A pond 20 to 25 cm deep lined with thick agricultural plastic, about 2 × 2 metres.
- A layer of fine soil, then cow manure diluted in water, and a little superphosphate.
- Water 10 to 15 cm deep, then 0.5 to 1 kg of fresh azolla as seed.
- After two weeks you can harvest 0.5 to 1 kg a day from the pond.
- Warning: azolla weakens above 35 degrees Celsius. In Gulf, Syrian and Jordanian summers it needs shade (50% shade net) and water renewal.
How to feed it
- Wash it well before feeding to remove the manure smell.
- Mix it with concentrate at first, because some cows refuse it on its own.
- Start with half a kilo and raise gradually to 1.5 – 2 kg per cow per day.
- Do not grow it in polluted water, because it absorbs heavy metals.
Frequently asked questions
- Does azolla replace concentrate?
- No. At normal amounts it replaces a very small part of it.
- How many kilos of azolla do I give a cow?
- 1.5 to 2 kg fresh per day, mixed with the concentrate.
- Can azolla be dried?
- Yes. It is dried in the shade, ground and mixed into the feed, which concentrates its value.
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