|
|
College of Agriculture |
| Veterinary Science | Mare Reproductive Loss Syndrome Index Page |
| Keeneland Session |
Mare Reproductive Loss Syndrome
Reproductive Status
Summary
May 24, 2001
Dr. Karen McDowell
Associate Professor
University of Kentucky College of Agriculture
Maxwell H. Gluck Equine Research Center
Department of Veterinary Science
With the help of The Jockey Club Information System, we are examining records from several central Kentucky Thoroughbred breeding farms. The information presented here summarizes data from 4 farms.
For the 2001 breeding season,
487 mares were bred between Feb 9 and May 2, 2001 and were declared to
be pregnant. Of those, 347 mares (71%) remain in foal, and 140 (29%)
had embryonic or fetal losses. The majority of these losses occurred
in mares bred earlier in the year. The table below shows running
2-week averages by breeding date.
| Dates Bred | Number of Mares Bred | % loss |
| Feb 9 – 17 | 35 | 77 |
| Feb 18 – March 3 | 110 | 49 |
| March 4 - 17 | 96 | 29 |
| March 18 – 31 | 75 | 26 |
| April 1 – 14 | 74 | 11 |
| April 15 – 28 | 65 | 3 |
| April 29 – May 12 | 32 | 3 |
The majority of losses (90%) were detected during the first 3 weeks of May, when veterinarians were examining mares in large numbers, having previously been alerted to the Early Fetal Loss problem. The average stage of gestation on which losses were reported was 60 days, corresponding to times when veterinarians were performing ultrasound examinations for fetal sexing and first noticed the problem.
The loss rates reported thus far for mares bred in April and early May (3-11%) are in agreement to what is normally observed for this time of year, and are not considered to be part of the 2001 Early Fetal Loss Syndrome.
