Other signs suggesting EMS include elevated blood triglyceride levels and leptin levels, hypertension, and reproductive changes in mares ( an increased diestrus period, and a lack of anestrus ).
12.
Therefore, many breeding farms begin to put mares " under lights " in late winter in order to bring them out of anestrus early and allow conception to occur in February or March.
13.
Hence, seasonal breeders can be divided into groups based on fertility period . " Long day " breeders cycle when days get longer ( spring ) and are in anestrus in fall and winter.
14.
The estrous cycle lasts about 19 22 days, with the average being 21 days . As the days shorten, the mare returns to a period when she is not sexually receptive, known as anestrus.
15.
The proestrus is relatively long at 5 7 days ( 9 days ), while the estrus may last 4 13 days, with a diestrus of 60 days followed by about 90 150 days of anestrus.
16.
Anestrus prevents the mare from conceiving in the winter months, as that would result in her foaling during the harshest part of the year, a time when it would be most difficult for the foal to survive.
17.
Some animals that are long day breeders include; Ring-tailed lemurs, Horses, Hamsters, Groundhogs, and Minks . " Short day " breeders cycle when the length of daylight shortens ( fall ) and are in anestrus in spring and summer.
18.
Anestrus-occurring in the majority of, but not all, mares-prevents the mare from conceiving in the winter months, as that would result in her foaling during the harshest part of the year, a time when it would be most difficult for the foal to survive.
