EE (Ether Extract / Crude Fat)
EE — Ether Extract — is the standard measure of crude fat content in cattle feed. It is determined by extracting a feed sample with petroleum ether (or a similar non-polar solvent), evaporating the solvent, and weighing the residue. The fraction extracted, expressed as a percentage of dry matter, is the EE.
EE includes true fats (triglycerides), free fatty acids, phospholipids, waxes, fat-soluble vitamins, and other ether-soluble compounds. The "crude" in crude fat reflects that it captures more than just fat — but for practical nutrition purposes EE is used as the fat measure.
Why EE matters
Fat is the most concentrated source of dietary energy — every gram of fat contains roughly 2.25 times more energy than a gram of carbohydrate or protein. This makes EE the easiest way to lift the energy density of a ration without bulking it up.
Three reasons EE matters specifically for dairy:
- Direct milk fat contribution. Dietary fatty acids are absorbed and used by the mammary gland to synthesise milk fat.
- Higher energy density. A high-EE ration delivers more total energy in less volume — critical when intake capacity limits production.
- Heat stress mitigation. Fat is metabolised with less heat production than carbohydrate or protein, so high-EE rations help animals cope with summer heat stress.
EE targets in cattle rations
| Animal class | EE target (DM basis) |
|---|---|
| Lactating cow | 3–5% |
| Lactating buffalo | 5–7% |
| Calf starter | 4–5% |
| Heifer | 3–4% |
| Dry cow / dry buffalo | 2–3% |
The buffalo target is significantly higher than cow because buffalo milk contains nearly twice the fat (6-7%) of cow milk (3.5-4.5%).
BIS-required EE for compound cattle feed
BIS IS:2052 specifies minimum EE values for compound cattle feed:
| Grade | EE (Crude Fat) minimum |
|---|---|
| Type-1 (premium) | 4% |
| Type-2 (standard) | 3% |
The higher EE in Type-1 is one of the three parameters (along with higher CP and lower CF) that distinguishes the premium grade.
EE in common Indian feed ingredients
| Ingredient | EE (DM basis) |
|---|---|
| Bypass fat | 99%+ |
| Full-fat rice bran | 14–20% |
| Cotton seed cake (premium expeller) | 12–14% |
| Groundnut cake (expeller) | 6–10% |
| Mustard cake (expeller) | 6–10% |
| Maize | 3.5–4.5% |
| Soybean meal (Normal) | 1% |
| Wheat bran | 3–4% |
| DORB | under 2% |
| Maize silage | 3–4% |
| Green fodder | 2–3% |
| Dry straw | 1–2% |
The 5% rumen fat ceiling
There is a hard practical limit on how much fat you can feed cattle through standard dietary ingredients: above approximately 5–6% of total DM intake, free fat coats fibre particles in the rumen and suppresses fibre digestion. This is why simply adding more oil-rich ingredients to a ration eventually backfires.
Two ways around this ceiling:
- Bypass fat — highly saturated or calcium-soap fat that doesn't melt or react in the rumen, bypassing the rumen ceiling entirely
- Distributed feeding — fat in small amounts at every concentrate feeding, rather than bolus doses
Practical use
For lactating buffalo at peak yield, the 5–7% ration EE target is achieved by combining cotton seed cake (12–14% EE), some expeller-grade mustard or groundnut cake, and 100–300 g/day of bypass fat. For cows, the lower 3–5% target is easier to reach without bypass fat for moderate yields, but high-yielders benefit from bypass fat supplementation.