122 TIMED ARTIFICIAL INSEMINATION IN WOOD BISON USING FROZEN-THAWED SEMEN

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.

2009 ◽  
Vol 21 (1) ◽  
pp. 171
Author(s):  
M. E. F. Oliveira ◽  
I. C. C. Santos ◽  
J. S. P. Pieroni ◽  
R. M. Ferreira ◽  
M. F. Cordeiro ◽  
...  

The aim this study was to evaluate the effect of the addition of LH in superovulatory response and embryo production in Santa Inês sheep. Ten donors with 60.3 ± 10.7 kg and BCS of 3.9 ± 0.3 were superovulated in a cross-over design, with a 60-day interval. Estrus was synchronized with a progesterone-releasing intravaginal device (CIDR™; Pfizer Animal Health, Brazil) inserted on Day 0 and replaced by a new one on Day 7, that was maintained to Day 14. Two doses of 37.5 g of D-cloprostenol (Prolise™, Arsa, Buenos Aires, Argentina) were administered, on Days 7 and 14. Donors also receive 256 mg of pFSH (Folltropin™, Bioniche, Belleville, ON, Canada) in 8 decreasing doses, starting on Day 12. On Day 14, all females received 200 IU of eCG (Novormon ™, Syntex, Argentina). On Day 15, the animals were homogeneously allocated in 1 of 2 groups: Control (GC, n = 10) and treated (G-LH, n = 10). Ewes in GC did not receive exogenous LH, whereas ewes in G-LH were treated with 7.5 mg of LH (Lutropin™, Bioniche), on Day 15. All females were inseminated by laparoscopy, with frozen–thawed semen, 42 and 48 h after CIDR removal. On Day 21, the embryos were surgically collected. The superovulatory response was classified in scores: (0) 4 or fewer CL; (1) between 5 and 10 CL, and (2) 11 or more CL. Means were compared using Kruskal-Wallis test and percentages using chi-square (P < 0.05). Most of donors (70%, 7/10) from G-LH presented a superovulatory response classified as score 2, and the remaining (30%, 3/10) as score 1, whereas, half of the controls were classified as score 2 and half as score 1. Ovulation rate tended to be greater in G-LH (135/158, 85.4% v. 105/135, 77.7%, P = 0.08). The number of CL (mean ± SD) was 10.5 ± 3.8 in GC and 13.5 ± 4.84 in G-LH, but was not statistically different. The number of anovulatory follicles (AF) did not differ between groups (GC: 3.0 ± 3.2; G-LH: 2.3 ± 1.6), but the proportion of AF tended to decrease in G-LH (30/135, 22.2% v. 23/158, 14.5%, P = 0.08). Considering embryo production, there was no difference between GC and G-LH (P > 0.05) related to number of recovered ova/embryos (6.1 ± 4.6 v. 8.4 ± 5.2), viable embryos (3.8 ± 4.3 v. 4.2 ± 5.2), unfertilized (1.7 ± 3.4 v. 2.0 ± 2.9) and degenerated embryos (0.7 ± 0.7 v. 2.2 ± 2.9), respectively. Data showed that the addition of LH tended to increase ovulation rate and to decrease the proportion of AF, but did not affect the number of viable embryos.


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).


2010 ◽  
Vol 22 (1) ◽  
pp. 258
Author(s):  
H. W. Vivanco ◽  
E. Huaman ◽  
S. Leon ◽  
A. Gallegos ◽  
M. Asparrin ◽  
...  

The objective of the study was to evaluate 4 superovulatory regimes in terms of the quantity of transferable embryos recovered. A total of 48 female alpacas, 3 to 5 years of age and located at Malkini Alpacas Farm (4100 m elevation), were distributed into 4 treatments. In treatment 1, 13 female alpacas received on Day 0 an intravaginal device containing 0.78 mg of progesterone (Cue Mate®, Bioniche Animal Health, Belleville, Ontario, Canada) followed immediately by an i.m injection of estradiol (1 mg of estradiol benzoate) and an i.m. injection of PGF2α (Veyx®, 0.25 mg of cloprostenol). The intravaginal device was removed on Day 7, performing at removal time an i.m. injection of estradiol. From Days 8 to 16, the alpacas received an i.m injection twice per day and 12 hours apart of pFSH (FolltropinV®, Bioniche Animal Health) in decreasing doses totaling 420 mg of pFSH; on Day 16,300 IU of eCGi.m. (Pregnecol®, Bioniche Animal Health) was injected. In treatment 2, 13 alpacas received on Day 0 an intravaginal device of progesterone followed by an i.m. injection of PGF2; from Days 5 to 9, alpacas received injections twice per day of decreasing doses of pFSH (porcine FHS) totaling 320 mg; on Day 7, the intravaginal device was removed and 500 IU i.m. of eCG was injected. In treatment 3,13 alpacas received on Day 0 an intravaginal device of progesterone followed immediately by an i.m injection of GnRH (Conceptal®, 0.0042 mg of acetate of busereline); pFSH was injected i.m. from Days 5 to 9 in decreasing doses twice per day, totaling 440 mg; the intravaginal device was removed on Day 7. In treatment 4, 9 female alpacas received on Day 0 an i.m. injection of GnRH after verifying the presence of a preovulatory follicle (>8.0 mm diameter). On Day 2, the alpacas received 1000 IU i.m. of eCG followed on Day 7 by an i.m. injection of PGF2. In all cases, the donor alpacas were evaluated by ultrasonography. The matings for treatments 1, 2, and 3 were performed twice per donor alpaca at 12-hour intervals between Days 5 and 8 of the initiation of the pFSH treatments, whereas in treatment 4 the matings were made the following day after the application of the PGF2. In treatment 1, the donor alpacas received at time of first mating an i.m injection of 3.75 mg of LH (Lutropin®, Bioniche Animal Health); in treatments 2, 3, and 4, the donors received an i.m. injection of GnRH. In all treatments, embryo collection was performed by nonsurgical method 6.5 days after first mating. There were significant differences between treatments (P < 0.05) in the mean number of CL, with treatment 4 being the highest (4.7 ± 2.63, 4.1 ± 3.05, 1.8 ± 1.8, and 6.0 ± 3.16 for treatments 1 to 4, respectively). The total number of blastocysts recovered per treatment was 7, 16, 2, and 18 for treatments 1 to 4, respectively. The superovulatory strategy followed for treatment 4 showed to be the one resulting in the highest number of transferable embryos. Further comparative evaluations between FSH and eCG treatments are recommended. Research was partially funded by the contributions of Bioniche Animal Health.


2021 ◽  
Vol 95 ◽  
Author(s):  
C.I. Cortés-Martínez ◽  
A.I. Rodríguez-Hernández ◽  
M.R. López-Cuellar ◽  
N. Chavarría-Hernández

Abstract The use of native entomopathogenic nematodes as biocontrol agents is a strategy to decrease the environmental impact of insecticides and achieve sustainable agriculture crops. In this study, the effect of the surface culture of Steinernema sp. JAP1 over two solid media at 23–27°C on infective juvenile (IJ) production and pathogenicity against Galleria mellonella larvae were investigated. First, the bacterial lawn on the surface of the media with egg yolk (P2) or chicken liver (Cl) were incubated in darkness at 30°C for 48 and 72 h, and 100 surface-sterilized IJs were added. Four harvests were conducted within the next 35 days and the mean accumulated production was superior on Cl (210 × 103 IJs) than on P2 (135 × 103 IJs), but the productivity decreased up to 10% when the incubation time of the bacterial lawn was of 72 h. The mean pathogenicity of in vitro- and in vivo-produced IJs were of 47–64% and 31%, respectively. It is worth noting that none of the two solid media had a statistically significant difference in IJ pathogenicity. Considering that the maximum multiplication factor of IJs on solid media was 2108 and that the pathogenicity against G. mellonella was outstanding, Steinernema sp. has a good potential for in vitro mass production.


2004 ◽  
Vol 16 (2) ◽  
pp. 213 ◽  
Author(s):  
J. Small ◽  
M. Colazo ◽  
D. Ambrose ◽  
R. Mapletoft ◽  
J. Reeb ◽  
...  

The objective was to evaluate the effect of pLH treatment on pregnancy rates in recipients receiving in vivo- or in vitro-produced bovine embryos. Heifers (n=37) and lactating (n=28) and non-lactating (n=150) beef cows were treated at random stages of the cycle with 100μg GnRH i.m. (Cystorelin, Merial Canada Inc., Victoriaville, Quebec, Canada) on Day −9, 500μg cloprostenol i.m. (PGF; Estrumate, Schering Plough Animal Health, Pointe-Claire, Quebec, Canada) on Day —2 and GnRH on Day 0 (66h post-PGF; without estrus detection). Cattle were placed at random, by class, into three groups: no further treatment (Control; n=71), or 12.5mg pLH (Lutropin-V, Bioniche Animal Health, Belleville, Ontario, Canada) on Day 5 (n=72) or on Day 7 (n=72) after the second GnRH. On Day 7, cattle with a CL &gt;10mm in diameter (determined ultrasonically) received in vivo-produced, fresh (Simmental) or frozen (Holstein), or in vitro-produced frozen (Holstein) embryos (embryo type balanced among groups). Embryos were cryopreserved in 10% ethylene glycol; in vivo-produced frozen embryos were thawed 5 to 10s in air, 15s in a water-bath at 30°C and then “direct-transferred” nonsurgically. In vitro-produced frozen embryos (donated by IND Lifetech Inc., Delta, British Columbia, Canada) were thawed in a water-bath at 27°C for 10s and placed in ViGro Holding Plus medium (AB Technology, Pullman, WA, USA) at room temperature, evaluated and then transferred nonsurgically. Pregnancy was determined by ultrasonography on Day 35. Data were analyzed with CATMOD, chi-square and GLM procedures (SAS Institute, Cary, NC, USA.). Twenty cattle (9.3%) did not receive embryos; five heifers had cervical problems, and five heifers and 10 cows did not have a CL &gt;10mm. Overall, 7.1% of the recipients had two CL on the day of embryo transfer. There was no effect (P&gt;0.05) of treatment, embryo type (or interaction) or class of recipient on pregnancy rate (overall, 44.1%, 86/195; Table 1). Similarly, mean (±SD) CL diameter and luteal area did not differ (P&gt;0.05) among groups or between pregnant and open recipients (overall, 22.0±3.4mm and 352.0±108.7mm, respectively). However, recipients with a CL diameter ≥18mm tended (P&lt;0.1) to have a higher pregnancy rate (45.8 vs 25.0%). In a subset of 40 recipients examined ultrasonically on Day 12, 50% of those treated on Day 5 and 70% of those treated with pLH on Day 7 had two CL. In summary, overall pregnancy rate in GnRH-synchronized recipients receiving in vitro- or in vivo-produced embryos by nonsurgical transfer was 44.1%. Embryo survival to Day 35 was not affected by type of embryo or treatment with pLH 5 or 7 days after ovulation. Table 1 Pregnancy rate in recipients on Day 35 based on pLH treatment and embryo-type


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4215
Author(s):  
João Bosco Loiola Filho ◽  
Alane Pains Oliveira do Monte ◽  
Thais Thatiane Dos Santos Souza ◽  
Mayara De Souza Miranda ◽  
Lívia Correia Magalhães ◽  
...  

To evaluate the effect of pFSH dose on the in vivo embryo production of Dorper ewes in the semi-arid northeast of Brazil, 40 sheep females were distributed into two groups of 20 animals that received intravaginal CIDR for 14 days, and two days before device removal, they received one of the following treatments: in the FSH200 group, the ewes received 200 mg of pFSH; and in the FSH128 group, the ewes received a total of 128 mg in decreasing doses every 12 h. Beginning 12 h after the conclusion of the treatments, estrus detection was performed every four hours using two Dorper rams of proven fertility. The ewes were mated at estrus onset and 24 hours later. Seven days after intravaginal device removal, the superovulatory response was evaluated, and embryo collection was performed using the laparotomy method. The recovered flushings were subjected to embryo searches under a stereomicroscope and classified according to their qualities. Analyses of variance (ANOVAs) and LSD tests were used to compare the different parameters. The data expressed as percentages were analysed by chi-square test. The ovulation rate was higher in the FSH200 group, which had 16.3 ± 0.3 corpora lutea (CL), than in the FSH128 group, which had 11.3 ± 0.3 CL (P<0.05). However, higher fertilization rate (83.6% vs. 62.4%) and higher transferable (86.0% vs. 71.6%) and freezable (67.9% vs. 40.8%) embryo rates were observed in the FSH 128 group compared with the group that received 200 mg. Furthermore, no significant differences in the remaining parameters were observed between the experimental groups (P>0.05), demonstrating that pFSH dose reduction promoted a greater production of freezable and transferable embryos in Dorper ewes subjected to MOET.


2011 ◽  
Vol 23 (1) ◽  
pp. 180
Author(s):  
C. A. Zanenga ◽  
C. M. Martins ◽  
N. C. Rodovalho ◽  
F. Aidar ◽  
J. F. Hasler ◽  
...  

Two experiments were conducted to compare conception rates following embryo transfer (ET) of bovine embryos held and transported in Syngro® holding medium (Bioniche, Belleville, Ontario, Canada) with other 2 holding media: Emcare® (ICPbio, Auckland, New Zealand) for in vivo-derived embryos and HEPES-buffered synthetic oviduct fluid (H-SOF) for IVF-derived embryos. The first trial was performed in the period from October through December 2006 at the Curitiba farm in Poços de Caldas, Minas Gerais, Brazil. A total of 140 in vivo-derived embryos were produced from 20 Nelore donor cows and transferred fresh at the same farm. After each donor recovery, embryos were equally separated per stage (morula or blastocyst) and classification (grades 1, 2, and 3) into 2 Petri dishes, each containing either Syngro or Emcare. The embryos were held for an average of 3 h after recovery, loaded into 0.25-mL straws, and transferred fresh into recipients heifers, which were all previously synchronized with the same hormonal protocol treatment and presented a corpus luteum on the day of transference. Conception rate was checked at approximately 60 days of conception by rectal palpation. The chi-square test was used for statistical analysis. The conception rate of embryos maintained in Syngro was significantly higher than those in Emcare: 64.2% (43/67) v. 47.9% (35/73; P < 0.05). A second experiment was performed between September and December 2008 at Embriza Biotechnology Laboratory, Campo Grande, Mato Grosso do Sul, Brazil. A total of 1689 IVF-derived embryos (stage = 7, quality = 1), produced from Nelore donor cows, were randomly assigned to be held and transported in either Syngro (769) or H-SOF transport medium (920). Transportation time ranged from 1 to 9 h, and the recipient farms ranged from 100 to 1200 km in distance from the Embriza Laboratory. Crossbred recipient heifers (Bos taurus × Bos indicus) were synchronized with prostaglandin or vaginal progesterone device protocols. Pregnancy diagnosis was performed by ultrasonography approximately 60 days after ET. Statistical comparisons were performed using the chi-square test. Conception rates resulting from embryos transported in Syngro (45.1%, 347/769) and in H-SOF (42.0%, 386/920) were not different (P = 0.19). Financial support from Embriza Biotecnology, Tecnopec LTDA, and Bioniche Animal Health


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4215 ◽  
Author(s):  
João Bosco Loiola Filho ◽  
Alane Pains Oliveira do Monte ◽  
Thais Thatiane Dos Santos Souza ◽  
Mayara De Souza Miranda ◽  
Lívia Correia Magalhães ◽  
...  

<p>To evaluate the effect of pFSH dose on the <em>in vivo </em>embryo production of Dorper ewes in the semi-arid northeast of Brazil, 40 sheep females were distributed into two groups of 20 animals that received intravaginal CIDR for 14 days, and two days before device removal, they received one of the following treatments: in the FSH200 group, the ewes received 200 mg of pFSH; and in the FSH128 group, the ewes received a total of 128 mg in decreasing doses every 12 h. Beginning 12 h after the conclusion of the treatments, estrus detection was performed every four hours using two Dorper rams of proven fertility. The ewes were mated at estrus onset and 24 hours later. Seven days after intravaginal device removal, the superovulatory response was evaluated, and embryo collection was performed using the laparotomy method. The recovered flushings were subjected to embryo searches under a stereomicroscope and classified according to their qualities. Analyses of variance (ANOVAs) and LSD tests were used to compare the different parameters. The data expressed as percentages were analysed by chi-square test. The ovulation rate was higher in the FSH200 group, which had 16.3 ± 0.3 corpora lutea (CL), than in the FSH128 group, which had 11.3 ± 0.3 CL (P&lt;0.05). However, higher fertilization rate (83.6% vs. 62.4%) and higher transferable (86.0% vs. 71.6%) and freezable (67.9% vs. 40.8%) embryo rates were observed in the FSH 128 group compared with the group that received 200 mg. Furthermore, no significant differences in the remaining parameters were observed between the experimental groups (P&gt;0.05), demonstrating that pFSH dose reduction promoted a greater production of freezable and transferable embryos in Dorper ewes subjected to MOET.</p>


1983 ◽  
Vol 29 (11) ◽  
pp. 1589-1591
Author(s):  
R. Turcotte ◽  
M. Ishaque

Mycobacterium lepraemurium was cultivated in vitro on Ogawa egg-yolk medium. The pathogenicity of the third and eighth subcultures for C3H and C57BL mice was compared with that of in vivo grown murine bacilli by evaluating the mean survival time of infected mice. The results strongly suggest that a significant drop of virulence occurs during the in vitro cultivation of M. lepraemurium.


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