Follicular wave dynamics after estradiol-17β treatment of heifers with or without a progestogen implant

Systemic administration of ovulation-inducing factor (OIF), discovered recently in seminal plasma of llamas, alpacas (induced ovulators), and cattle (spontaneous ovulators), stimulated ovulation in >90% of female llamas and alpacas. The objective of the present study was to test the hypothesis that purified OIF from llama seminal plasma would induce ovulation in cattle. Peripubertal heifers, weighing 323 � 27 kg, were used to minimize the confounding effect of spontaneous ovulation. Heifers (n = 11/group) were treated intramuscularly with 1.0 mg/100 kg of purified OIF, 100 µg of GnRH (positive control), or 2.5 mL of phosphate-buffered saline (negative control). Ovarian dynamics were monitored daily by transrectal ultrasonography for 10 days post-treatment. Blood samples were collected at 0.5- to 1-h intervals for 8 h, beginning at the time of treatment. Ovulation occurred in 9/11 (82%) of GnRH-treated heifers and in 1/11 (9%) heifers in each of the OIF- and saline-treated groups (P < 0.05). A surge in plasma LH concentration was detected within 30 min of treatment in the GnRH group (2.2 � 0.1 ng mL–1; P < 0.05), but remained at the basal level in the OIF- and saline-treated groups (0.3 � 0.1 and 0.2 � 0.1 ng mL–1, respectively). The onset of regression of the dominant follicle present at the time of treatment was earlier (P < 0.05) in OIF- v. saline-treated heifers (3.1 � 0.6 days v. 6.0 � 0.7 days). The interval from treatment to follicular wave emergence was shorter (P < 0.05) in GnRH- and OIF-treated heifers than in those treated with saline (1.1 � 0.4 days, 1.5 � 0.3 days, and 3.1 � 0.3 days, respectively). A similar pattern was observed for emergence of the second follicular wave (5.1 � 0.7 days, 4.6 � 0.5 days, and 6.6 � 0.4 days, respectively). Purified OIF did not induce ovulation in heifers but hastened both the regression of the extant dominant follicle and follicular wave emergence. Results provide a rationale for the hypothesis that OIF from seminal plasma is involved in controlling follicular wave dynamics in spontaneously ovulating species (e.g., Bos taurus) through a suppressive effect on the dominant follicle. The mechanism of action on ovarian follicular wave dynamics, as well as species specificity, remains to be elucidated.

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THE EFFECTS OF DAILY INJECTIONS OF oFSH BETWEEN TWO ENDOGENOUS FSH PEAKS ON FOLLICULAR WAVE DYNAMICS IN ANESTROUS EWES

Biology of Reproduction ◽

10.1093/biolreprod/77.s1.222c ◽

2007 ◽

Vol 77 (Suppl_1) ◽

pp. 222-223

Author(s):

Behzad Toosi ◽

Ashley Ziegler ◽

Srinivas Seekallu ◽

David Barrett ◽

Norman Rawlings

Keyword(s):

Wave Dynamics ◽

Follicular Wave

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173 ESTRADIOL-17β CONCENTRATIONS IN BLOOD AND MILK DURING SUPEROVULATORY TREATMENT IN DAIRY COWS

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab173 ◽

2010 ◽

Vol 22 (1) ◽

pp. 245

Author(s):

R. Dupras ◽

J. Dupras ◽

Y. Chorfi

Keyword(s):

Los Angeles ◽

Dairy Cows ◽

Artificial Insemination ◽

Animal Health ◽

Follicular Wave ◽

Milk Samples ◽

Pfizer Animal Health ◽

Estradiol 17Β

In cows, estradiol-17β is usually used to synchronize follicular wave emergence during superovulatory treatment. This approach, however, raises some concerns about the presence of estrogens in bovine products and their possible association with some human estrogen-sensitive cancers. The objective of this study was to determine estradiol-17β concentrations in blood and milk of dairy cows after i.m. injection of estradiol-17β and to compare these concentrations to those obtained during standard superovulation protocols. Six cows were used for this experiment. On Day 0, corresponding to Day 7 of their ensuing cycle, cows received 4.5 mg of estradiol-17β (Gentes et Bolduc, St-Hyacinthe, Québec, Canada) via i.m. injection and a progesterone-releasing vaginal insert (1.9 g of progesterone, CIDR, Pfizer Animal Health, Kirkland, Québec, Canada). Blood and milk samples were taken at 0, 24, 48, and 72 h after injection. From Day 4 evening to Day 8 evening, the cows received a total of 380 mg of NIH-FSH-P1 (Folltropin-V, Bioniche Animal Health, Belleville, Ontario, Canada) administered i.m. through 9 injections of decreasing dose (from 70 to 20 mg) at 12-h intervals. On Day 7, the cows received 2 injections consisting of 500 μg of cloprostenol (prostaglandin F2 α analogue, Estrumate, Shering-Plough, Pointe-Claire, Québec, Canada) given approximately 12 h apart and vaginal inserts were removed 12 h after the last injection. Artificial insemination was performed on Day 9 and 10 after treatment with 100 μg of GnRH i.m. (Cystorelin, Merial Canada Inc., Baie Urfe, Québec, Canada). A second batch of blood and milk samples was taken at Day 8, 9, 10, and 11. Measurement of estradiol-17β was performed with an IMMULITE chemiluminescent counter using an IMMULITE Estradiol Kit (Siemens Diagnostic Products Corporation, Los Angeles, CA, USA). Concentrations of estradiol-17β in blood (37.1 ± 15.6 pg mL-1 at 24 h, 19.1 ± 14.2 pg mL-1 at 48 h) and milk (38.4 ± 29.5 pg mL-1 at 24 h, 9.3 ± 4.9 pg mL-1 at 48 h) were significantly higher after i.m. injection of 4.5 mg of estradiol-17β. In comparison, superovulation heat (Day 9 to 11) increased estradiol-17β concentrations in blood (20 ± 13.6 pg mL-1 at 24 h, 32.5 ± 16.3 pg mL-1 at 48 h) but not in milk.

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The evolution of improved and simplified superovulation protocols in cattle

Reproduction Fertility and Development ◽

10.1071/rd11919 ◽

2012 ◽

Vol 24 (1) ◽

pp. 278 ◽

Cited By ~ 24

Author(s):

Reuben J. Mapletoft ◽

Gabriel A. Bó

Keyword(s):

Embryo Transfer ◽

Treatment Protocol ◽

Bovine Embryo ◽

Treatment Protocols ◽

Wave Dynamics ◽

Follicular Wave ◽

Recent Treatment ◽

Gonadotrophin Releasing Hormone ◽

Animal Handling ◽

On Farm

Superovulation protocols have improved greatly since the early days of bovine embryo transfer when purified gonadotrophins were not available, follicular wave dynamics were unknown physiological phenomena and prostaglandins were not available. Although superstimulatory protocols in cattle are normally initiated mid-cycle, elective control of follicular wave emergence and ovulation have had a great impact on the application of on-farm embryo transfer. However, the most common treatment for the synchronisation of follicular wave emergence involves the use of oestradiol, which cannot be used in many parts of the world. Therefore, the need for alternative treatments has driven recent research. An approach that has shown promise is to initiate follicle-stimulating hormone (FSH) treatments at the time of the emergence of the new follicular wave following ovulation induced by gonadotrophin-releasing hormone. Alternatively, it has been shown that it may be possible to ignore follicular wave status and, by extending the treatment protocol, induce subordinate follicles to superovulate. Finally, the short half-life of pituitary FSH necessitates twice-daily treatments, which are time-consuming, stressful and subject to error. Recent treatment protocols have permitted superstimulation with a single FSH treatment or two treatments 48 h apart, reducing the need for animal handling during gonadotrophin treatments.

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