Studies On Changes Of Serum Concentrations Of Reproductive Hormones During The Estrous Cycle In Cattle And Buffaloes In Guangxi

These studies were conducted to investigate changes of serum concentrations of such four reproductive hormones as follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and progesterone (P4) being assayed during the estrous cycle in cattle and buffaloes in Guangxi. Results have indicated as follows:1 .The time of animals estrus in cattle which received PMSG (intramuscular injection, i.m) and PG (i.m) was 7h earlier than that in cattle which received PMSG (i.m) and PG (uterus perfusion) during synchronization; The time of animals estrus in buffaloes which received PMSG (i.m) and PG (i.m) was 24h earlier than that in buffaloes which received PMSG (i.m), PG (uterus perfusion) and LH(i.m) during synchronization.2.Comparing to the spontaneous cattle, there was a significant difference(P <0.05) in total LH concentration of the estrous cycle in synchronized cattle, while there was a significant difference(P<0.05) in FSH concentration of oestrum(Day 0~l) in synchronized buffaloes as compared to spontaneous ones. However, there was no any difference(P>0.05) in the total E2 concentration of estrous cycle in synchronized cattle or buffaloes as compared to spontaneous ones, respectively.3. There were two E2 surges from the day of treatment to the day of oestrus in cattle or buffaloes, the first one was before estrus and the second one was after estrus while the time of LH surge.4. The surge time of E2, FSH and LH in cattle and buffaloes which received PMSG (i.m) and PG (i.m) was 56h(29.94±2.18pg/ml), 60h(16.85±3.96mIU/ml), 60h(23.41±2.19mIU/ml) and 24h(25.15± 11.79pg/ml), 60h(8.65±1.02mIU/ml), 63h(21.41±5.38mIU/ml) after treatment, respectively; while the surge time of E2, FSH and LH in cattle and buffaloes which received PMSG (i.m) and PG (uterus perfusion) [or +LH(i.m)] was 54h(24.89±11.45pg/ml), 72h(7.34±0.59mIU/ml), 77h(21.74±1.86 mlU/ml) and 48h(30.38±14.05pg/ml), 80h(8.66±0.92mIU/ml), 82h (18.85±1.01 mlU/ml) after treatment, respectively.5. P4 level on Day 0 (the day of oestrus) in both synchronized and spontaneous cattle or buffaloes was the lowest (cattle: <0.7ng/ml; buffalo: < 0.5ng/ml) and reached the highest level on Day 8~16 in cattle or Day 7~18 in buffaloes during the estrous cycle.