Toddler milk is cows milk. It's just got vitamins in it too.
The ingredients for Aptamil 2-3 milk are as follows (my bolding)
Water, Skimmed Milk, Lactose (from Milk), Galacto Oligosaccharides (GOS) (from Milk), Vegetable Oils, Fructo-Oligosaccharides (FOS), Acidity Regulator (Citric Acid), Emulsifier (Mono- and Diglycerides of Fatty Acids), Fish Oil, Magnesium Hydrogen Phosphate, Vitamin C, Calcium Hydroxide, Calcium Citrate, Potassium Citrate, Milk Flavouring, Potassium Hydroxide, Calcium Phosphate, Ferrous Lactate, Taurine, Vitamin E, Zinc Sulphate, Vitamin A, Vitamin D3, Pantothenic Acid, Nicotinamide, Copper Gluconate, Sodium Selenite, Folic Acid, Potassium Iodide, Thiamin, Biotin, Vitamin B6, Vitamin B12, Vitamin K1, Riboflavin, Manganese Sulphat
Save yourself some money and give him milk.