Some owners feed alfalfa to add extra vitamins and minerals to their horse’s diet, others will feed a double handful of chaff to add fibre, while many worry about adding more than a small cupful of extra feed to their horse’s bucket in case it gets too much protein.
In every case, the amount fed makes very little difference to a horse’s overall dietary supply of nutrients. A typical horse (500kg) will eat 10kg of total feed per day and each of the examples above contributes just 500g to the daily diet.
What this does highlight is that there is a huge difference between the emotional need we have to do the right thing for our horses, and the reality — that these things hardly have a significant effect.
The ability of a feed to deliver the promised nutrition depends on the concentration of the nutrients within it. A rich source will only deliver an appreciable amount if significant quantities are fed.
For instance, alfalfa is rich in calcium, containing 1.5% calcium in every bite. This means that a double handful of alfalfa weighing 200g gives 3g of calcium.
Cubes and mixes are also rich in calcium, containing 1-1.2%, depending on the manufacturer. If you feed two scoops per day (about 3kg), you will be supplying about 33g of calcium.
The same is true for protein. Balancers are high in protein (typically 18%), whereas low-energy feeds are not (typically 10%). However the former is fed at a small amount each day (600g) yielding 100g of protein, whereas 2kg of low-energy feed supplies 200g.
The good news is that small additions, like those detailed above, are unlikely to do any harm by unbalancing the diet.
Comparing values of typical feedstuffs
| Feed | Weight | Rich in | Weight | Value |
| Large net of hay | 8kg | Fibre (35%) | 2,500g | High |
| Large net of haylage | 10kg | Fibre (30%) | 2,100g | High |
| Standard scoop of conditioning cubes | 1.5kg | Protein (16%) | 240g | High |
| One scoop of oats | 1kg | Starch (45%) | 450g | High |
| Double handful of chop or chaff | 250g | Fibre (25%) | 63g | Low |
| Typical “glug” of oil | 150g | Oil (99%) | 150g | Med |
| 5kg of 7% oil feed | 5kg | Oil (7%) | 350g | High |
| One scoop sticky mix | 1kg | Sugar (molasses) | 90g | Low |
