Sentence:  Some mares do not show signs of being in heat even when tried ("teased") regularly with a stallion, but they often can be <WSD>settled</WSD> either by natural or artificial service, provided the approximate time of ovulation is determined and they are not suffering from either a diseased or abnormal condition of the reproductive system. 
Meaning of the word marked with <WSD> tags:  To make or become pregnant.