RESUMEN
The side of ovulation (left ovary, LO; right ovary, RO) and side of the next ovulation were compared between (1) beginning and end of an interovulatory interval (IOI) and beginning and end of consecutive sets of two and three IOI (n = 900 IOI), (2) beginning and end of the IOI for two and three follicular waves per IOI (n = 1300), and (3) beginning of pregnancy and first postpartum ovulation (n = 793). Pairs of sides of ovulation were designated LL (LO and LO), RR, LR, and RL. The frequency of ovulation pairs for two ends of an IOI was not different from two ends of two or three consecutive IOI indicating that differences between LO and RO were more likely inherent than from factors that developed in each IOI. For each end of an IOI or two consecutive IOI, the least frequency (P < 0.05) was for LL (16 %) with no differences among RR, LR, and RL (28 % for each). Frequencies between ipsilateral (LL, RR) and contralateral (LR, RL) ovulations pairs were not different for two-wave IOI (48 % compared with 52 %) but differed (P < 0.0001) for three-wave IOI (32 % compared with 68 %) and for pregnancy/postpartum (34 % compared with 66 %). In pregnancy/postpartum, each pair was different (P < 0.05) from each other: LL (13 %), RR (21 %), LR (30 %), RL (36 %). The lesser frequency for LL than for any of the others for an IOI, consecutive IOI, and pregnancy/postpartum indicated a ubiquity of the small propensity for LO ovulation.
Asunto(s)
Bovinos/fisiología , Ovario/fisiología , Ovulación/fisiología , Preñez , Animales , Femenino , Embarazo , Preñez/fisiologíaRESUMEN
The mechanisms underlying the greater frequency of ovulation from right ovary (RO) than left ovary (LO) were studied in 145 Bos taurus heifers. Diameter deviation during a follicular wave is indicated by continued diameter increase in the future preovulatory follicle (PF) and a decrease in diameter of future subordinate follicles. The PF (ovulation) was in the RO (63/105, 60%) more frequently (P < 0.04) than in the LO (40%) for ovulatory wave 2 of two-wave interovulatory interval (IOI) but not for wave 3 of three-wave IOI (RO, 45%; LO, 55%). The difference between waves 2 and 3 was associated with a greater (P < 0.01) number of 6-mm follicles during predeviation in the RO (2.3 ± 0.2 follicles) than LO (1.8 ± 0.1) for wave 2 but not for wave 3. Combined for ovulatory waves 2 and 3, the PF developed in the ovary with more 6-mm follicles during more (P < 0.0001) ovulatory waves (72%) than when the PF developed in the ovary with fewer follicles (11%). Ovulation from RO was more frequent (P < 0.02) when both PF and CL were in RO (46/72, 64%) than in LO (36%), but not when PF was alone in RO without the CL. Results supported the hypotheses that: (1) the number of 6-mm predeviation follicles developing during the ovulatory wave is greater for RO and (2) the number of predeviation follicles is greater for the ovary in which the preovulatory follicle subsequently develops.
Asunto(s)
Bovinos/fisiología , Cuerpo Lúteo/fisiología , Folículo Ovárico/fisiología , Ovulación , Animales , Células Cultivadas , Cuerpo Lúteo/citología , Femenino , Folículo Ovárico/citologíaRESUMEN
In lactating cattle, the incidence of twin calving has many negative impacts on production and reproduction in dairy farming. In almost all cases, natural twinning in dairy cattle is the result of double ovulation. It has been suggested that the milk production level of cows influences the number of ovulatory follicles. The objective of the present study was to investigate the incidence of double ovulations during the early postpartum period in relation to the productive and reproductive performance of dairy cows. The ovaries of 43 Holstein cows (26 primiparous and 17 multiparous) were ultrasonographically scanned throughout the three postpartum ovulation sequences. The incidence of double ovulation in the unilateral ovaries was 66.7%, with a higher incidence in the right ovary than in the left, whereas that in bilateral ovaries was 33.3%. When double ovulations were counted dividing into each side ovary in which ovulations occurred, the total frequency of ovulations deviated from a 1:1 ratio (60.3% in the right side and 39.7% in the left side, P < 0.05). In multiparous cows, double ovulation occurred more frequently than in primiparous cows (58.8% vs. 11.5% per cow and 30.0% vs. 3.8% per ovulation, respectively P < 0.01). The double ovulators experienced more anovulatory repeated waves of follicles before their first ovulations than the single ovulators, which resulted in an extension of the period from parturition to third ovulation (81.5 days vs. 64.2 days, P < 0.05). In the multiparous cows, the double ovulators exhibited higher peak milk yield (P < 0.01) with lower milk lactose concentration (P < 0.05), indicating the prevalence of a more severe negative energy balance during the postpartum 3-month compared to the multiparous single ovulators. Our results showed that, regardless of their parity, double ovulation had no impact on the reproductive performance of the cows. Two multiparous cows that experienced double ovulation during the early postpartum period subsequently conceived twin fetuses. It can be speculated that the incidence of double ovulations during the early postpartum period partly contributes to the increased incidence of undesirable twin births in multiparous dairy cows.
Asunto(s)
Bovinos/fisiología , Ovulación , Periodo Posparto , Complicaciones del Embarazo/veterinaria , Embarazo Múltiple , Animales , Femenino , Incidencia , Embarazo , Complicaciones del Embarazo/epidemiologíaRESUMEN
PIP: 14 female buffaloes of Murrah breed were examined to determine the progesterone (P) concentration in the blood during an estrous cycle. In addition an effort was made to predict early pregnancy from the data. Animals were checked for heat daily. Blood was collected on Days 1, 3, 7, 11, 15, and 19 of the estrous cycle and P was estimated by radioimmunoassay. The concentration of P on the day of estrus was .5ng/ml and was similar on Day 3. A peak value of 1.6 ng/ml was reached on Day 15. Thereafter the peak continued to increase slightly until Day 19 in buffaloes which conceived but dropped in the 3 animals which failed to conceive. Pregnancy prediction embryonic mortality or persistent corpus luteum.^ieng
Asunto(s)
Búfalos/sangre , Estro , Preñez , Progesterona/sangre , Animales , Femenino , Embarazo , Pruebas de Embarazo/veterinariaRESUMEN
PIP: Plasma progesterone levels were determined in 24 early pregnant ferrets by competitive protein binding. Progesterone levels rose from about 4 ng/ml on estrus to a peak of about 35 on Day 12 when implantation occurs, staying above 30 until Day 16. These results agree with those of Heap and Hammond (1974), rather than those of Blatchley and Donovan (1976), whose peak levels were lower and occurred on Day 14.^ieng
Asunto(s)
Carnívoros/fisiología , Implantación del Embrión , Hurones/fisiología , Progesterona/sangre , Animales , Femenino , Embarazo , PreñezRESUMEN
PIP: At the University Hospital in Louvain, Belgium, plasma hormonal fluctuations in 6 women, aged 16-46, were studied. Measurements were made during the nonpregnant state and in the 4 women who conceived also in the period around nidation. Measurements during the nonpregnant state yielded expected results: Preovulatory midcycle luteinizing hormone (LH) surge preceded by increase of estrone and estradiol, sudden fall of estrogens and rise of progesterone during or just after LH surge, and secondary estrogen rise together with progesterone peak during the luteal phase accurred. In the women implantation occurred, human chorionic gonadotropin (HCG) started to rise sharply 10 or 11 days after the LH surge. Progesterone and estrogen levels remained high during the implantation period. In the patient who aborted at 17 weeks of pregnancy, the HCG rise was slower and the secondary rise of estradiol was rather limited; progesterone levels, however, appeared to be normal. An estradiol surge may occur just prior to implantation.^ieng