There are a few problems with feeding cow's milk to baby humans.
1. It contains bovine beta casein A1. During digestion, this is broken down into a 7-amino acid peptide chain beta-casomorphin7 (BCM7), which appears to cause issues (e.g. increased gut permeability) increasing the RR of diseases like Type 1 Diabetes and Ischaemic Heart Disease. See http://www.ncbi.nlm.nih.gov/pubmed/?term=A1[All%20Fields]%20AND%20%22beta-casein%22[All%20Fields]%20AND%20%22humans%22[MeSH%20Terms]%20AND%20%28hasabstract[text]%20AND%20%22humans%22[MeSH%20Terms]%29 A solution is to use A2 milk, or goat's milk which is apparently naturally A2. See also Further research for consideration in 'the A2 milk case'.
2. It's much higher in protein (4g/100mL) than human breast milk (1.1g/100mL), as baby cows are supposed to grow very rapidly, unlike baby humans. As 80% of the protein in milk is casein, and casein is joined to calcium as calcium caseinate, this increases the calcium intake, and too much calcium relative to magnesium is constipating. A solution is to increase magnesium intake, or dilute 1 part cow's milk with ~3 parts water & add some coconut oil, to get the fat content back up to 4.4g/100mL.
Continued on Cow's milk, Schizophrenia and Autism.