310 DOES PROGESTERONE OR EQUINE CHORIONIC GONADOTROPIN IMPROVE THE SUPEROVULATORY RESPONSE AND EMBRYO QUALITY IN WOOD BISON DURING THE ANOVULATORY SEASON?

2013 ◽  
Vol 25 (1) ◽  
pp. 302
Author(s):  
J. M. Palomino ◽  
R. J. Mapletoft ◽  
M. Anzar ◽  
M. R. Woodbury ◽  
M. P. Cervantes ◽  
...  

Superovulation protocols are being developed in wood bison (Bison bison athabascae), a threatened Canadian species. In initial studies, 2 doses of FSH diluted in hyaluronan given 48 h apart were successful for inducing ovarian superstimulation in wood bison, and ovulation rate was improved by final treatment with hCG instead of LH (Palomino et al. 2012 Reprod. Fertil. Dev. 24, 226). In that study, exogenous progesterone had no effect on the number of ovulations, but embryo quality could not be evaluated because of the low number of embryos collected. In beef cattle, replacement of the final doses of FSH with eCG has resulted in the recovery of a greater number of ova/embryos. The objective of the present study was to evaluate the effect of exogenous progesterone (PRID) on embryo quality and to determine if the addition of eCG increases the ovulation rate in superstimulated wood bison. Follicular ablation was done to synchronize follicular wave emergence in 26 wood bison cows during the anovulatory season (May). Cows were assigned randomly to 3 groups: PRID/no eCG (n = 8), PRID/eCG (n = 9), and no PRID/eCG (n = 9). A PRID was inserted on the day of follicular ablation (Day –1) in respective groups. In all bison, FSH diluted in hyaluronan (5 mg mL–1, MAP-5, Bioniche Animal Health Inc., Belleville, Ontario, Canada) was given intramuscularly on Day 0 (300 mg) and Day 2 (100 mg). On Day 3, a single dose of 450 IU of eCG (Pregnecol, Bioniche Animal Health Inc.) was given intramuscularly and the PRID were removed in the corresponding groups. On Day 5, all bison were given 2500 IU of hCG (Chorulon, Merck, Whitehouse Station, NJ, USA) intramuscularly to induce ovulation. Bison were inseminated with chilled semen 12 and 24 h later. Nonsurgical embryo collection was performed on Day 14. Transrectal ultrasonography was done to record the ovarian response, ovulation rate, and number of corpora lutea (CL). Results were compared by ANOVA and Chi-squared test (Table 1). The number of ovulatory-sized follicles (≥9 mm) on Day 5 did not differ among groups. Ovulation rate was lowest in bison treated with both a PRID and eCG (P < 0.05). There were no differences among groups in the number of CL on Day 14, the number of ova/embryos collected, or the number of transferable embryos. The superovulatory response and embryo collection rate in the present study were higher than in any previous reports in bison. The ovulation rate was not improved by the addition of eCG treatment, and exogenous progesterone had no effect on embryo quality. Table 1.Response of superstimulated wood bison (mean ± SEM) to treatment with exogenous progesterone (PRID) and/or eCG

2014 ◽  
Vol 26 (1) ◽  
pp. 220
Author(s):  
J. M. Palomino ◽  
R. J. Mapletoft ◽  
M. R. Woodbury ◽  
M. P. Cervantes ◽  
G. P. Adams

In an effort to conserve a threatened Canadian species, Bison bison athabascae, we developed an embryo collection protocol subsequent to superovulatory treatment involving two doses of FSH diluted in hyaluronan given 48 h apart. The follicular response to superstimulatory treatment was satisfactory, but many follicles did not ovulate, thus limiting the number of embryos collected. Based on recent results in cattle, where replacement of the final doses of FSH with a low dose of eCG resulted in the recovery of a greater number of ova/embryos, the objective of the present study was to evaluate the effect of adding eCG to the superovulatory protocol to increase ovulation rate, embryo collection, and embryo quality in wood bison during the breeding season (September). Ovarian synchronization was induced in wood bison (n = 24) by treatment with a luteolytic dose of prostaglandin (500 mcg, Cloprostenol) followed 8 days later by transvaginal ultrasound-guided follicular ablation. Follicular wave emergence (Day 0) was defined as the day after follicle ablation. Bison were assigned randomly to two groups: FSH (n = 12) and FSH+eCG (n = 12). FSH was diluted in hyaluronan (5 mg mL–1, MAP-5, Bioniche Animal Health, Belleville, ON, Canada) and given intramuscularly on Day 0 (300 mg) and Day 2 (100 mg) in both groups. Bison in the FSH+eCG group received 450 IU eCG (Pregnecol, Bioniche Animal Health) intramuscularly on Day 3, and bison in both groups were administered a luteolytic dose of prostaglandin on Day 3. On Day 5, bison were given 2500 IU hCG (Chorulon, Merck Animal Health, Summit, NJ, USA) intramuscularly to induce ovulation. The bison were artificially inseminated with chilled semen 12 and 24 h after hCG treatment. Nonsurgical embryo collection was performed on Day 13. The ovaries were examined by transrectal ultrasonography on Days 5, 7, and 13 to record the follicular response, ovulation rate, and number of corpora lutea (CL), respectively. Results were compared between groups by t-test or chi-square test (Table 1). The number of ovulatory-sized follicles (≥9 mm), ovulation rate (number ovulations/ovulatory-sized follicles), number of CL, number of ova/embryos, and number of transferable embryos were not different between groups (P = 0.23, P = 0.19, P = 0.25, P = 0.18, P = 0.09, respectively). In conclusion, the superovulatory response and embryo collection rate in wood bison approached that observed in cattle, but were not improved by the addition of a low dose of eCG. Table 1.Response of wood bison (mean ± s.e.m.) to superovulatory treatment with or without eCG


2015 ◽  
Vol 27 (1) ◽  
pp. 270
Author(s):  
M. W. von der Porten ◽  
M. P. Cervantes ◽  
J. M. Palomino ◽  
G. P. Adams

Wood bison are a species threatened by endemic brucellosis and tuberculosis. Reproductive technologies are being developed in an effort to ensure the genetic diversity of wild wood bison, and to prevent disease transmission to healthy bison, livestock, and humans. For the purposes of IVF, recent results revealed that cumulus cell expansion was more extensive in in vivo- v. in vitro-matured cumulus-oocyte complexes (COC), and more oocytes reached maturity after 30 v. 24 h of in vivo maturation following hCG treatment (Cervantes et al. 2013 Reprod. Fert. Develop. 25, 283). An experiment was designed to determine the effects of an additional 4 h of in vivo maturation on follicle development, unwanted ovulation, and COC collection efficiency. Wood bison cows (n = 28) underwent transvaginal ultrasound-guided follicle ablation to induce emergence of a new follicular wave (Day 0 = day of wave emergence, 1 day after ablation) during the non-breeding season. Bison were given FSH diluted in hyaluronan IM on Days 0 (300 mg) and 2 (100 mg), and 2500 IU hCG IM on Day 4. Bison were then assigned randomly to 2 groups (n = 14 per group) in which transvaginal oocyte collection was done at either 30 or 34 h after hCG treatment. The number and size of follicles available for aspiration (i.e. = 5 mm) was compared between groups by Student's t-test. Binomial data (COC collection rate and ovulation rate) were compared by chi-square, and the proportion of cows that ovulated was compared using a Fisher's exact test. Ovulation was defined as the sudden disappearance of follicles ≥10 mm from the hCG treatment to the time of COC collection. The numbers of follicles ≥5 mm and ≥10 mm at the time of COC collection were not different between the 30 and 34 h groups (19.0 ± 1.4 v. 17.4 ± 2.4, and 9.5 ± 1.2 v. 7.7 ± 1.8), nor was the average size of follicles = 5 mm (9.9 ± 0.2 v. 9.8 ± 0.2 mm). The number of follicles aspirated was similar between the 30 and 34 h groups (16.4 ± 1.4 v. 13.4 ± 2.1), but the pre-collection ovulation rate was lower in the 30 h group (12/89 [13.5%] v. 47/147, [32.0%]; P = 0.003), as was the proportion of bison that ovulated (3/14 v. 10/14, P = 0.02). The COC collection rate was lower in the 30 v. 34 h group (64.3% v. 78.2%; P = 0.003), but the total number of COC collected per bison was similar (10.6 ± 1.7 v. 10.5 ± 1.5). Although waiting for 34 h before COC collection resulted in a larger proportion of unwanted ovulations, a greater collection efficiency in the 34 h group resulted in a similar number of COC collected per bison. We conclude that the 30 to 34 h in vivo maturation window provides flexibility for the purposes of oocyte collection and immediate in vitro fertilization in wood bison.We thank Bioniche Animal Health for providing FSH (Folltropin-V) and hyaluronan (MAP-5), and Merck Animal Health for hCG (Chorulon).


2016 ◽  
Vol 28 (2) ◽  
pp. 191 ◽  
Author(s):  
G. P. Adams ◽  
S. X. Yang ◽  
J. M. Palomino ◽  
M. Anzar

Recent progress with methods to control ovulation and semen cryopreservation in Wood Bison was the impetus to test the feasibility of timed AI to facilitate reclamation of this threatened species. A 2 × 2 design was used to compare the efficacy of 2 ovulation synchronization techniques and 2 semen cryopreservation protocols. Female Wood Bison were assigned randomly to 2 groups (n = 24/group) in which ovarian synchronization was induced by ultrasound-guided ablation of follicles >5 mm or intramuscular treatment with 2.5 mg of estradiol 17B + 50 mg of progesterone (E+P) in canola oil. A progesterone-releasing intravaginal device (PRID) was placed at the time of follicle ablation (for 5 days) or E+P treatment (for 8 days) in the respective groups. A luteolytic dose of prostaglandin was given at the time of PRID removal, and 2500 IU of hCG was given IM 3 days later. Bison were inseminated 24 and 36 h after hCG treatment using frozen-thawed semen. The semen was collected by electro-ejaculation from 4 Wood Bison bulls, pooled, and divided into aliquots diluted in either egg-yolk extender (EY) or cholesterol-loaded cyclodextrin extender (CLC). Half the bison in each synchronization group were inseminated with either EY- or CLC-extended semen. Bison were examined by ultrasonography every 12 h beginning on the day of hCG treatment for 3 days or until ovulation was detected, whichever occurred first. Pregnancy diagnosis was made by ultrasonography 34–36 days after insemination. Two bison were excluded during the experiment because of handling difficulty; therefore, the total number of bison used was 46. Ovulation rate and interval to ovulation were compared between synchronization groups by chi-square and t-test, respectively. Pregnancy rates were compared among groups by 2-way ANOVA after transforming data to arcsin. The ovulation rate was not different between synchronization groups [combined mean, 37/46 (80%)], nor was the degree of synchrony, as assessed by the residuals (variation from the mean) in the respective groups. However, the diameter (mean ± standard error of the mean) of the dominant follicle at the time of hCG treatment was smaller in the follicle ablation group than in the E+P group (10.5 ± 0.6 v. 13.9 ± 0.6; P < 0.04), and the interval from hCG treatment to ovulation tended to be longer (35.3 ± 1.6 v. 31.8 ± 1.3 h; P ≤ 0.10). Pregnancy rate was not affected by synchronization procedure, but pregnancy was detected only in the EY-inseminated group (9/23 v. 0/23; P < 0.01). Despite that post-thaw sperm motility was similar for EY and CLC semen (41.7 ± 2.9 and 44.6 ± 3.3%; respectively), CLC-treated semen failed to impregnate bison in vivo. We concluded that synchronization and timed insemination with frozen-thawed semen is feasible in Wood Bison. Of the 23 bison inseminated with EY-extended semen, 21 ovulated (91%), and of those that ovulated 9 became pregnant (43%). Both synchronization schemes were effective, but the ablation protocol may be improved by an additional day between ablation and hCG treatment. We thank Vetoquinol Canada and Merck Animal Health for providing hormone treatments.


1992 ◽  
Vol 134 (1) ◽  
pp. 11-18 ◽  
Author(s):  
R. G. Glencross ◽  
E. C. L. Bleach ◽  
B. J. McLeod ◽  
A. J. Beard ◽  
P. G. Knight

ABSTRACT To study the effects of immunoneutralization of endogenous inhibin on gonadotrophin secretion and ovarian function, prepubertal heifers (n = 6) were actively immunized against a synthetic peptide replica of the N-terminal sequence of bovine inhibin α subunit bIα(1–29)Tyr30) coupled to ovalbumin. In contrast to ovalbumin-immunized controls (n=6), bIα(1–29)Tyr30-immunized heifers had detectable inhibin antibody titres (% binding to 125I-labelled bovine inhibin at 1:2000 dilution of plasma) of 17 ± 3% (s.e.m.) at puberty, rising to 31 ± 5% by the end of the study period 7 months later. Neither age (immunized: 295 ± 8 days; controls: 300 ± 5 days) nor body weight (immunized: 254 ± 13 kg; controls 251 ± 9 kg) at onset of puberty differed between groups. Although the difference did not reach statistical significance, mean plasma FSH concentrations recorded in inhibin-immunized heifers remained 35–40% higher than in controls throughout the 12-week period leading up to puberty (P = 0·14) and during nine successive oestrous cycles studied after puberty (P=0·10). Plasma LH concentrations did not differ between groups at any time during the study. Inhibin immunization had no effect on oestrous cycle length (immunized: 19·8±0·5 days; controls: 19·9±0·5 days). However, in comparison with controls, inhibinimmunized heifers had more medium sized (≥0·5 to <1 cm diameter) follicles during both the preovulatory (95%, P<0·001) and post-ovulatory (110%, P < 0·05 waves of follicular growth and more large (>1 cm diameter) follicles during the preovulatory wave (49%, P<0·05). In addition, the number of corpora lutea observed during the post-ovulatory phase of each cycle was significantly greater in the inhibin-immunized group (43%, P<0·01), as was the recorded incidence of cycles with multiple ovulations (19/56 in the inhibin-immunized group compared with 0/54 in controls; P<0·001). All six inhibinimmunized heifers had at least one cycle with multiple ovulation whereas none of the control heifers did so. These results support the conclusion that immunoneutralization of endogenous inhibin using a synthetic peptide-based vaccine can enhance ovarian follicular development and ovulation rate in heifers. Whether this ovarian response is dependent upon the expected increase in secretion of FSH remains to be established. Journal of Endocrinology (1992) 134, 11–18


1991 ◽  
Vol 3 (5) ◽  
pp. 551 ◽  
Author(s):  
JP Ryan ◽  
JR Hunton ◽  
WM Maxwell

In a factorially designed experiment (N = 321), 0, 800 or 1600 I.U. pregnant mare serum gonadotrophin (PMSG) were administered in combination with 0, 12 or 18 mg follicle stimulating hormone (FSH-P) to superovulate Merino ewes in autumn and spring. A moderate dose of PMSG (800 I.U.) in conjunction with 12 or 18 mg FSH-P increased the ovulation rate above that observed when FSH-P was used alone. This was accomplished by (i) increasing the proportion of ewes that exhibited a superovulatory response (greater than 3 corpora lutea (CL) or persistent large follicles (LF): 69/70 (99%) v. 55/74 (74%), P less than 0.001), and (ii) in those ewes that exhibited a superovulatory response, by an additive effect of exogenous gonadotrophin (14.8 +/- 0.9 CL (69) v. 11.3 +/- 0.9 CL (55), P less than 0.01) without increasing the incidence of LF. The use of 1600 I.U. PMSG in conjunction with 12 or 18 mg FSH-P was characterized by an increase in the number of LF and, in comparison with 800 I.U. PMSG, a reduction in ovulation rate. Season had no effect on the numbers of CL, but total ovarian response (CL + LF) was higher in autumn than in spring (P less than 0.01), because of a greater incidence of LF (P less than 0.001). The proportion of ewes with regressed CL was higher in autumn than in spring (53/143 (37%) v. 32/156 (21%), P less than 0.01), and increased with increased dose of gonadotrophin. Furthermore, a nutritional component to the incidence of ewes with regressed CL was suggested by the observation that the mean concentration of plasma glucose was higher for ewes with normal CL than for ewes with regressed CL (P less than 0.05). Rates of ova or embryo recovery, fertilization and embryo development generally declined with an increase in the incidence of LF as a result of increases in the dose of gonadotrophin and season of administration.


2010 ◽  
Vol 9 (2) ◽  
pp. 1
Author(s):  
O. I. Azawi, and M. K. M. A. Al-Mola

The present study was undertaken to investigate the contribution of laparoscopic insemination to the improvement of fertilization and embryo recovery. The experiment was conducted in the breeding season. Twelve nonpregnant and cycling Awassi ewes of 3-4 years of age were randomly allocated in equal number (n = 6) to two groups. Each ewe was treated with progesterone impregnated intravaginal sponge for 12 days. All ewes were superovulated with eCG (equine chorionic gonadotropin) 1200 IU once by intramuscular injection 48 h prior to sponge removal. Ewes of group 1 were mated naturally at least two times with Awassi rams of proven fertility. Ewes of group 2 had intrauterine insemination and were conducted 44-46 h after sponge removal, under laparoscopic visualization of uterine horns, depositing 1 ml of semen in the distal portion of each uterine horn. Ovarian response was assessed by determining the number of corpora lutea by laparoscopy on day 6 after mating. Embryo recovery was performed by semi-laparoscopic and by flushing of both uterine horns. Results of the present study revealed a high number of unfertilized ova (P<0.05) was observed in ewes when naturally inseminated than ewes inseminated intrauterine using the laparoscopic technique. The higher rate of embryo recovery (P<0.05) was achieved when ewes inseminated via intrauterine (4.66 ± 0.66) than ewes naturally mated (2.16 ± 0.74). The fertilization rate in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 79.93% and 40.07%, respectively. Fertilization failure in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 7.37% and 49.35%, respectively. It could be concluded that the use of eCG to induce superovulation in Awassi ewes combined with laparoscopic intrauterine insemination can increase the fertilization rate.


2012 ◽  
Vol 24 (1) ◽  
pp. 224
Author(s):  
A. Garcia Guerra ◽  
A. Tribulo ◽  
J. Yapura ◽  
J. Singh ◽  
R. J. Mapletoft

The present study was designed to test the hypothesis that an increase in the length of exposure of ovulatory follicles to progesterone and FSH during ovarian superstimulation will increase the number of ovulations and viable embryos in cattle. Twenty-four beef cows were initially subjected to follicle ablation at random stages of the oestrous cycle to determine the number of follicles at wave emergence; cows with comparable numbers of follicles were randomly allocated to groups by replicate. A single dose of prostaglandin F2α (PGF; Estroplan, Vétoquinol, QC, Canada) was given IM 7 to 9 days after follicle ablation and daily ultrasound examinations were performed to detect ovulation. Follicular ablation of all follicles ≥5 mm was done 5 to 8 days after ovulation and a progesterone-releasing intravaginal device (PRID, Vétoquinol) was inserted. The Control group (n = 12) was treated with 4 days of FSH and cows in the Long group (n = 12) were given 7 days of FSH treatment. The FSH treatments were initiated 1.5 days after ablation (Day 0) with a total dose of 400 mg of NIH-FSH-P1 (Folltropin-V; Bioniche Animal Health, Belleville ON, Canada). The total dose of FSH was distributed equally over 8 (Control) or 14 (Long) IM injections at 12-h intervals. Prostaglandin F2α was administered twice (at 12-h intervals) on Day 2 (Control) or Day 5 (Long) and PRID were removed 12 h after the last PGF. Both groups received 25 mg of porcine LH (pLH) IM (Lutropin-V; Bioniche Animal Health) 24 h after PRID removal and AI with frozen–thawed semen of proven fertility was done 12 and 24 h later. A third AI was done 12 h later in cows with 2 or more follicles ≥9 mm (12/12 and 9/12 in Control and Long groups, respectively; P = 0.22). All animals were subjected to transrectal ultrasonography every other day and at the time of ova or embryo collection. Ova or embryos were collected nonsurgically 7 days after the pLH injection and evaluated following IETS guidelines. Embryos were defined as transferable (Grades 1, 2 and 3) and freezable (Grades 1 and 2). Procedure Genmod was used to compare variables between treatments and results are presented as means ± SEM (Table 1). There was no significant difference in the total numbers of ova/embryos recovered, but there were more ovulations, corpora lutea (CL), fertilized ova and transferable and freezable embryos in the Long group (P < 0.05). Collection efficiency (number of ova/embryos over the number of CL) was lower in the Long group (P < 0.05). In summary, lengthening of the superstimulatory treatment resulted in an increased number of ovulations without a decrease in oocyte or embryo competence. Data suggest that the traditional 4-day superstimulatory treatment protocol provides inadequate time to maximize ovulatory response. Table 1.Superovulatory response (mean ± SEM) of cows subjected to a conventional 4-day (Control) or a 7-day (Long) treatment protocol


2010 ◽  
Vol 22 (1) ◽  
pp. 363
Author(s):  
T. Huanca ◽  
O. Cardenas ◽  
M. Gonzales ◽  
W. Huanca ◽  
L. A. Quintela ◽  
...  

The objective of this study was to evaluate the ovarian response in alpacas to superstimulatory treatment with FSH and eCG. Alpacas females (n = 49) were examined daily by transrectal ultrasonography using a 7.5-MHz linear-array transducer (Aloka SSD500, Tokyo, Japan) to determine ovarian follicular dynamics. Alpacas (n =41) were selected when a growing follicle ≥7 mm in diameter was detected and were given an i.m. injection of 4 μg of buserelin (Conceptal®, Intervet, Millsboro, MD, USA) on Day 0 (i.e. beginning of treatment). On Day 2, alpacas were assigned to 1 of the following 2 treatments: (1) the FSH group (n = 21), which received a total dose of 200 mg NIH-FSH-P1 of pFSH (Folltropin®-V, Bioniche Animal Health Inc., Belleville, Ontario, Canada) in decreasing dosages of 52, 48, 40, 32, and 28 mg divided in twice-daily i.m. injections for 5 days; and (2) the eCG group (n = 20), which received a single dose of 750 IU of eCG (Folligon®, Intervet, Millsboro, MD, USA). Animals received an i.m. dose of 0.150 mg of triapost (PGF; Iliren, Intervet, Millsboro, MD, USA) on Day 6. On Day 7, ovaries of all alpacas were examined by transrectal ultrasonography, followed by mating and embryo collection on Day 14. Data were analyzed by ANOVA. The mean number of follicles <7 mm in diameter was 5.8 ± 1.0 and 3.2 ± 0.9 for those treated with FSH and eCG, respectively (NS). The number of follicles 7 to 13 mm in diameter was 5.8 ± 1.5 and 9.7 ± 1.2 for the FSH and eCG groups, respectively (P < 0.05). The number of follicles >13 mm in diameter was 0.3 ± 0.4 and 1.0 ± 0.3 for the FSH and eCG groups, respectively (NS). The mean (± SD) follicle diameter was 8.3 ± 0.3 and 9.0 ± 0.2 for the FSH and eCG groups, respectively (NS). The mean (± SD) number of CL was 6.0 ± 1.9 and 8.7 ± 2.3 for the FSH and eCG groups, respectively (NS). Only 82.9% of animals (34/41) were flushed and embryos were recovered in 18 animals (52.9%), with 2.7 ± 0.4 and 2.7 ± 0.7 embryos in the FSH and eCG groups, respectively (NS). Large unovulated follicles (diameter >13 mm) were observed in 34.1% of animals (14/41) on Day 14 and most of them (71.4%) were in the group treated with eCG (10/14; P < 0.05). In conclusion, the use of eCG resulted in a higher number of preovulatory follicles (7-13 mm in diameter) than FSH. However, the percentage of animals with large unovulated follicles was also higher in the eCG-treated group, resulting in no differences in the number of CL counted or embryos obtained per treatment.


2012 ◽  
Vol 24 (1) ◽  
pp. 226 ◽  
Author(s):  
J. M. Palomino ◽  
R. B. McCorkell ◽  
M. Anzar ◽  
M. R. Woodbury ◽  
N. Hawkins ◽  
...  

Brucellosis and tuberculosis are endemic in Wood Buffalo National Park, the largest reserve of wood bison (Bison bison athabascae) in Canada. Our goal is to produce and preserve disease-free embryos for the purpose of wood bison repopulation. This study was designed to determine if embryo collection is feasible in wood bison during the anovulatory season (May–July) and to test if progesterone priming is required for superovulation. A 2-by-2 design was used to determine the effectiveness of LH (Lutropin) or hCG (Chorulon) for induction of ovulation with or without intravaginal progesterone releasing device (PRID) in 32 wood bison cows. Follicular wave emergence was synchronized among bison by transvaginal ultrasound-guided follicle ablation. Synchronized bison were assigned to 4 groups: PRID+LH (n = 12), PRID+hCG (n = 4), no-PRID+LH (n = 12) and no-PRID+hCG (n = 4). A PRID was inserted on the day of follicular ablation in the respective groups. A single SC dose of 400 mg FSH (Folltropin) in a slow-release formulation was given the day after follicular ablation (i.e. on the expected day of a new follicular wave emergence, Day 0). The PRID was removed on Day 4 and either 25 mg LH or 2000 IU hCG was given IM on Day 5. Artificial insemination was done at 24, 36 and 48 h after LH or hCG treatment. Embryos were collected nonsurgically on Day 13 using commercial bovine equipment. Transrectal ultrasonography was done on Days 0, 5, 6, 7, 8 and 13 to record follicular and ovulatory responses. Count data (mean ± SEM) were analysed by two-way ANOVA and proportions by chi square. The number of ovulatory-sized follicles (≥10 mm) on Day 5 did not differ among groups (P = 0.33; Table 1). Ovulation rate (number of ovulations/number of follicles ≥10 mm) was greater in bison treated with hCG (P < 0.05; Table 1). The number of corpora lutea (CL) on Day 13 was greater in bison treated with hCG without a PRID (P < 0.05; Table 1). No differences in number of ova/embryos and transferable embryos were found among groups (P = 0.36 and P = 0.52, respectively; Table 1). In conclusion, progesterone priming (PRID) had no effect on ovarian superstimulation in wood bison in the anovulatory season. The ovulatory response was satisfactory only in bison treated with hCG. Embryo collection is feasible in wood bison, but the reasons for a low embryo collection rate in all groups remain unclear. Table 1.Response to superovulation and embryo collection in wood bison Funded by Advancing Canadian Agriculture and Agri-Food and Agri-Food Innovation.


2019 ◽  
Vol 31 (1) ◽  
pp. 221
Author(s):  
J. A. Abecia ◽  
A. Meikle ◽  
M. I. Vázquez ◽  
A. Casao ◽  
F. Forcada ◽  
...  

Twenty-three Rasa Aragonesa aged ewes (average age: 10.3±0.3 years) were used to determine the effect of melatonin on ovulatory response, embryo production, and endometrial expression of progesterone receptors (PR) after superovulation. Ewes were treated (M, n=13) or not (control, C, n=10) with melatonin implants in March (Day 0, Northern Hemisphere autumn), and received intravaginal progestogen sponges for 14 days on Day 77. Superovulatory treatments consisted of 8 doses in decreasing concentrations (2 mL×2 and 1 mL×6) of 176 NIH-FSH-S1 units of NIADDK-oFSH-17 (Ovagen, ICPbio Reproduction, Auckland, New Zealand) administered twice daily starting 72h before sponge removal. Seven days after oestrus, embryos were recovered by laparotomy, ewes were killed, and uterine horns were processed to study PR expression by immunohistochemistry. The amount of PR was estimated subjectively by 2 independent observers in 5 endometrial compartments: luminal epithelium (LE), superficial (sGE) and deep (dGE) glandular epithelia, and superficial (sS) and deep (dS) stroma. The extent of staining was expressed on a scale from 0 to 100. Data were analysed with a 2×2 factorial ANOVA. Melatonin implants improved fertilization (92v. 57%, for M and C groups, respectively; P&lt;0.01), blastocyst (47v. 9%; P&lt;0.01), viability (88v. 31%; P&lt;0.0001), and freezability (69v. 21%; P&lt;0.001) rates. Specifically, melatonin induced a significant reduction of the number of non-viable (degenerate and retarded) embryos (0.3v. 1.5; P&lt;0.05) and increased blastocysts (2.8v. 0.8; P&lt;0.05) per ewe. Melatonin treatment decreased PR staining intensity (47v. 55%; P&lt;0.05), but this effect was not observed when the individual cell types were compared (Table 1). Because the number of corpora lutea (CL) was responsible for different PR expression in both groups (P&lt;0.0001), animals were divided into 2 ovulation rate categories: &lt;10 CL and ≥10 CL, with lesser PR expression in the ≥10 CL group (P&lt;0.0001); this lower PR immunostaining in ≥10 CL is consistent with progesterone down-regulation of its own receptor. An interaction among number of CL and treatment was found for embryo quality (P&lt;0.05); thus, the positive effect of melatonin on this parameter was particularly effective in the low-ovulation-rate group. These results demonstrate that melatonin treatment in the autumn improves embryo quality in aged ewes, and that this effect is not explained by a differential endometrial sensitivity to progesterone. Table 1.Embryo production (mean±s.e.m.) in melatonin-treated (M) and control (C) ewes after superovulation in autumn, and staining intensity of progesterone receptors in the endometrium (CL=corpora lutea)


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