Effects of melatonin implants in pony mares 2. Long-term effects
| Autor: | Gene E. Robinson, M.R Peltier, Dan C. Sharp |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Ovulation
endocrine system medicine.medical_specialty Ovariectomy Photoperiod animal diseases media_common.quotation_subject Radioimmunoassay Ovary Biology Melatonin Random Allocation Estrus Food Animals Internal medicine Seasonal breeder medicine Animals Endocrine system Horses Least-Squares Analysis Small Animals reproductive and urinary physiology media_common Drug Implants Estrous cycle Estradiol urogenital system Equine Luteinizing Hormone Endocrinology medicine.anatomical_structure Ovariectomized rat Regression Analysis Female Animal Science and Zoology Seasons sense organs Luteinizing hormone medicine.drug |
| Zdroj: | Theriogenology. 49:1125-1142 |
| ISSN: | 0093-691X |
| DOI: | 10.1016/s0093-691x(98)00061-2 |
| Popis: | The effects of melatonin implant treatment over a 4 wk period at the summer solstice on the transition into and out of the following anovulatory season were evaluated in ovary-intact and ovariectomized mares. Melatonin implants tended to delay the timing of the final ovulation of the breeding season (P = 0.0797) in the ovary-intact mares. Although the decline in LH secretion associated with the end of the breeding season was parallel between treatments and ovarian statuses, the rate of LH secretion, as expressed by its mathematical accumulation, was lower in ovariectomized, melatonin-treated mares than in ovariectomized, control mares suggesting that melatonin administration advanced the offset of the breeding season in ovariectomized mares (P = 0.0001). The first ovulation of the subsequent breeding season was significantly delayed in the melatonin-treated mares as compared with that of control mares (P = 0.0031). During reproductive recrudescence, the time of the onset of the increase in LH secretion was similar among all 4 groups but the patterns of LH secretion were different for each treatment and ovarian status combination (P = 0.0112). Mares with melatonin implants had a slower rate of increase in LH secretion than control mares (P = 0.0001), and ovariectomized mares had a faster rate of LH increase than intact mares (P = 0.0001). These results suggest that melatonin implants during the summer solstice can alter the annual reproductive rhythm in mares and support the concept that endocrine patterns of reproductive recrudescence are not entirely independent of the ovary. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect