There have always been dogs native to North America. They were not introduced into the U.S. from Another Country or continent.
1999
Dogs come into heat every 6 months.
Most dogs come into season approximately every six months (twice a year) but for some dogs it can be one to four times a year.
Immigrants come to the US every year. There has never been a single year of US history in which there were no immigrants.
It is difficult to determine the exact number of abused dogs in the US each year as many cases go unreported. However, national organizations estimate that hundreds of thousands of dogs are abused or neglected annually.
Over 1000 dogs.
By calling them "dogs dressed in red who have come to rob us," and attacking the British in the Ohio country in 1763.
everyday
2000
in the year of 1528
As a rule, Dogs come in 'HEAT' twice a year. They generally can have puppies after they are 1 year old, and every year after that. One litter a year usually. It is recommended that dogs don't get pregnant the first time they come in Heat.
the year 1320