Post-partum, ovarian function in dairy cows as revealed by concentrations of oestradiol-17 beta and progesterone in defatted milk
| Autor: | P. Gyawu, G.S. Pope |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Ovulation
endocrine system medicine.medical_specialty media_common.quotation_subject Ice calving Biology Andrology Pregnancy Internal medicine medicine Animals Dairy cattle Progesterone Post partum media_common Estrous cycle General Veterinary Estradiol Ovary Postpartum Period Progesterone secretion medicine.anatomical_structure Endocrinology Milk Herd Cattle Female Corpus luteum hormones hormone substitutes and hormone antagonists |
| Zdroj: | The British veterinary journal. 146(3) |
| ISSN: | 0007-1935 |
| Popis: | Concentrations of oestradiol-17 beta and progesterone in defatted milk have been used to study the post-partum restoration of ovarian function in 52 autumn-calved dairy cattle. In 32 cows the first preovulatory peaks in oestradiol-17 beta concentration (indicative of imminent ovulation) were less than or equal to 15 days and in 49 cows less than or equal to 49 days post partum. Delay to first ovulation was mainly due, not to failure of ovarian secretion of oestradiol-17 beta at preovulatory level, but to failure of oestradiol-17 beta at this level to exert its normal preovulatory function. Longer intervals to first ovulation were associated with longer intervals from calving to the clearance of placental oestradiol-17 beta, high peak milk yields and high body weight losses, suggesting that in high-yielding dairy cows these factors (themselves inter-related) may be associated with others, which are the immediate cause of the inhibition of the normal, preovulatory function of oestradiol-17 beta. Forty-eight per cent of cows had short, first ovulation cycles. Ovarian function, comprising oestradiol-17 beta secretion at preovulatory level, normal preovulatory function of oestradiol-17 beta and normal corpus luteum progesterone secretion were almost fully restored in this herd by the 49th day post partum. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|