From Egyptian Secrets of Albertus Magnus, Joseph H. Peterson edition:
To make a Cow give a good supply of Milk.
When a cow, for the first time, calves, or while carrying a calf, give her half of the tail of an eel on a half slice of bread, and henceforth she will give milk in abundance.
The grimoire Egyptian Secrets of Albertus Magnus lists this spell.
Timeline of related events
1725Publication of Egyptian Secrets of Albertus Magnus (lists this spell)
1869English-language translation of Egyptian Secrets (lists this spell)