How to predict the exact mating stage during the 21 days cyclic period in cow??
this is the depends on the external sign or behaviour of the animal, which shows. for the cattle it 30-48 hr after the first sign of the behaviour as well external symptom of "heat" or say "oestrous". At this time one can mate or inseminate the sperm in to the genital track.
for this you may refer veterinary gynaecology book.
It is during the oestrus, best chances of conception are during "standing heat"