9 weeks to 2 months
it takes at least two months for a shih tzu to have puppies.bigger shih tzus it takes THREE to FOUR months to have puppies
Estrus in a cow or heifer only lasts for ~24 hours.
21 days
Shih Tzu puppies first open their eyes about 10 days after birth.
according to http:/wwwzperiodzcalzperiodznet/~pamgreen/length_of_estruszperiodzhtml about 3-4 weeks
If you're breeding, a shih tzu should be able to go to a new home when he / she is 8 - 12 weeks old (I suggest 12, this way they no longer need their mother for nursing).
A Shih Tzu's pregnancy typically lasts around 63 days, from the time of conception to giving birth. It is important to monitor the mother's health and prepare for the arrival of the puppies during this time.
Same amount for a beef cow: estrus is around 24 hours. Estrous is 21 days long.
2
Mice are in estrus for a period of about 10 to 12 hours, and they will go into estrus every 3 or 4 days.
Despite their small and furry bodies, Shih Tzu's can run fairly fast. They can run between six and eight miles an hour.
Most pregnancies last 3 months on average.