Effect of different protocols for estrus synchronization on reproductive performance of Santa Inês ewes under Amazon environmental conditions

The objective of this study was to evaluate the effect of different hormonal protocols on the reproductive performance of Santa Inês ewes in Amazon environmental conditions. Twenty-two Santa Inês ewes between 3 and 4 years-old were distributed in a randomized block experimental design, where the treatments consisted of two protocols for estrus synchronization (short and long) with eleven animals each. Data on the occurrence of estrus were described for each protocol. Data of estrus, pregnancy, and prolificity were firstly subjected to ANOVA and a subsequent Tukey’s test. Results were considered significant at p ≤ 0.05. The short-term protocol presented an interesting successful rate, where above 70% ewes tested had estrus. The long-term protocol also achieved a high successful rate, where above 80% ewes tested had estrus. However, comparing the protocols, the long-term protocol presented better results of positive estrus and pregnancy rates in ewes. Thus, it can be concluded that both protocols presented satisfactory results regarding estrus manifestation, and prolificity (lambs produced per ewe). However, under Amazon environmental conditions, the long-term protocol presented better results regarding positive manifestation of estrus and pregnancy rate.

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Melengestrol acetate, estradiol-17β and GnRH for synchronization of estrus and ovulation in beef cows

Canadian Journal of Animal Science ◽

10.4141/a98-089 ◽

1999 ◽

Vol 79 (1) ◽

pp. 39-43 ◽

Cited By ~ 6

Author(s):

J. Thundathil ◽

J. P. Kastelic ◽

W. O. Olson ◽

R. B. Cook ◽

R. J. Mapletoft

Keyword(s):

Key Words ◽

Pregnancy Rate ◽

Beef Cows ◽

Pregnancy Rates ◽

Conception Rate ◽

Estrus Synchronization ◽

Short Term ◽

Melengestrol Acetate ◽

Conception Rates ◽

Estradiol 17Β

Three experiments were conducted with suckled crossbred beef cows to determine the efficacy of various short-term regimens for synchronizing estrus or ovulation and to determine whether feeding melengestrol acetate (MGA) after timed AI will increase pregnancy rate. In exp. 1, all cows (n = 141) were given 0.5 mg MGA head−1 d−1 for 7 d (days 1 to 7), 1 or 5 mg E17β (and 100 mg progesterone) or 100 µg GnRH on day 1, and 500 µg cloprostenol on day 7. There were no significant differences among groups for estrous or synchronized conception rates (average, 84.4 and 52.1%, respectively). With an identical protocol in exp. 2 (78 cows), by day 11, cows given 5 mg E17β had the highest estrous and synchronized pregnancy rates (65.4 and 42.3%), compared to 1 mg E17β (46.2 and 15.4%) and GnRH (34.6 and 11.5%). Cows not detected in estrus were timed-inseminated and given 100 µg GnRH, 100 h after cloprostenol. There were no significant differences among groups for synchronized conception rate to timed AI (65.0%) or synchronized pregnancy rate to all inseminations (56.4%). Overall, 5 mg E17β gave the most consistent results. In exp. 3, 84 cows were given 100 µg GnRH on days 1 and 9, 500 µg cloprostenol on day 7, and were timed-inseminated on day 10. Half were fed MGA (0.5 mg head−1 d−1) on days 16 to 22, but the pregnancy rate was not different from that in the remaining cows (55.0 versus 47.8%, P > 0.5). Key words: Ovary, follicles, estrus synchronization, beef cows

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10 PREGNANCY RATE IN DAIRY COWS CROSSBREED HOLSTEIN × CARORA, DURING TWO SEASONS OF THE YEAR UNDER TWO ESTRUS SYNCHRONIZATION PROGRAMS AND TROPICAL CONDITIONS IN VENEZUELA

Reproduction Fertility and Development ◽

10.1071/rdv18n2ab10 ◽

2006 ◽

Vol 18 (2) ◽

pp. 113

Author(s):

M. Cabezas ◽

J. Cardenas ◽

T. Diaz ◽

A. A. Kowalski

Keyword(s):

Dairy Cows ◽

Pregnancy Rate ◽

Reproductive Performance ◽

Dairy Herd ◽

Pregnancy Rates ◽

Estrus Synchronization ◽

Gnrh Analog ◽

Tropical Conditions ◽

Breeding Groups ◽

The Tropics

Two experiments were performed in a commercial farm located in Lara, Venezuela. The objective was to evaluate the pregnancy rate in postpartum dairy cows with different genetic composition of Holstein (H) and Carora (C) breeds (1/2, 3/4, and 7/8) during two seasons of the year using estrus synchronization programs. The first experiment evaluated the pregnancy rate of three different breeding groups in two seasons of the year. All cows (n = 305) were treated with the Heatsynch program (Select Sires, Inc., Miami, FL, USA): Cycling cows between Days 36 and 42 after parturition were injected with two doses of PGF2� 14 days apart. Seven days later, after the last injection of PGF2�, the cows were injected with a GnRH analog (Buserelin). Seven days later cows were injected with PGF2� and after 24 h cows were injected with 1 mg of estradiol cypionate (ECP). Cows were inseminated when heat was detected, and after 48 h all cows that did not present heat were inseminated. During the period from January to May, 152 cows were treated. The average temperature (T) was 25.22�C and relative humidity (RH) was 70.16%. During the period from June to October, 153 cows were treated. The T was 25.26�C and RH was 72.58%. The pregnancy rates for the groups were 1/2H � C, n = 89, 28.08%; 3/4H � C, n = 143, 25.17%; and 7/8H � C, n = 73, 26.02%; they were not significantly different (P < 0.14). However, the pregnancy rate was higher in January-May (30.92%) than in June-October (22.87%; P < 0.05). The second experiment evaluated pregnancy rates in the different breeding groups (H � C), using two protocols, Heatsynch vs. Ovsynch (Select Sires, Inc.). The Ovsynch program is similar to the Heatsynch program; however, the last injection of ECP in the Heatsynch program is changed to the GnRH analog after 48 h from the last injection of PGF2�. Cows were inseminated 24 h after the GnRH injection. Pregnancy rate was lower for cows treated with the Heatsynch program (21.15%) than for those treated with the Ovsynch program (45.28%; P < 0.01). Furthermore, cows in the 1/2 and 3/4 breeding groups had higher pregnancy rates than those in the 7/8 breeding group (1/2 = 42.05%, 3/4 = 38.33%, and 7/8 = 16.72%; P < 0.01). Data were analyzed using logistic regression analysis. In conclusion, the introduction of the Carora breed in the dairy herd increased the adaptability of the Holstein cows to tropical conditions by increasing their reproductive efficiency. Furthermore, pregnancy rates were increased using synchronization programs that did not require heat detection. This demonstrated the possibility of increasing reproductive performance in the tropics by incorporating estrus synchronization systems that do not require heat detection. These studies also demonstrated that the incorporation of dairy breeds adapted to tropical conditions, such as the Carora breed, aids in improving reproductive performance under high RH conditions.

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Comparison of the effects of Presynch-Ovsynch, Presynch- Ovsynch+CIDR, and G6G protocols on the reproductive performance of lactating Holstein cows in the postpartum period

Veterinarska stanica ◽

10.46419/vs.53.4.6 ◽

2021 ◽

Vol 53 (4) ◽

Author(s):

Hesam Kohsari ◽

Khatereh Berenjian

Keyword(s):

Serum Concentration ◽

Pregnancy Rate ◽

Reproductive Performance ◽

Body Condition Score ◽

Dairy Farm ◽

Fixed Time ◽

Pregnancy Rates ◽

Holstein Cows ◽

Treatment Protocols ◽

Ovulatory Follicle

This study was performed on an industrial dairy farm near Tehran province, Iran, on 666 lactating Holstein cows from September 2019 to June 2020 in order to eliminate the harmful effects of heat stress on the reproductive performance of the cows. The hypothesis of the recent study was that by increasing the serum concentration of progesterone (P4) in the luteal phase before insemination in the form of Presynch-Ovsynch+CIDR (POC) and G6G protocols, the pregnancy rate of cows would be increased compared to the Presynch-Ovsynch (PO) protocol. The aim of the present study was to evaluate the effects of Presynch-Ovsynch (PGF2α-14d- PGF2α-12d-Ovsynch (OVS: GnRH(GnRH1)- 7d-PGF2α(PG)-2d-GnRH)-18h-Fixed-time artificial insemination (FTAI), n=212), Presynch-Ovsynch+CIDR (similar to the PO protocol, plus the use of a CIDR for 7 days, from the start of the OVS+FTAI protocol to the time of PG injection, n=230), and G6G (PGF2α- 2d-GnRH-6d-OVS+FTAI, n=224) protocols on the reproductive performance and pregnancy rate of lactating Holstein cows. The average body condition score (BCS) for the cows was about 2.5 at the time of the onset of the OVS+FTAI program. The average daily milk production for cows at the time of the start of the OVS+FTAI program was 38.3 kg/day. On average, the studied cows were inseminated 86 days postpartum. Implementation of the G6G protocol in comparison to the PO and POC protocols increased the serum concentration of P4 at GnRH1 (P=0.04). The cows that received the G6G protocol had a greater number of corpuses luteum (CL) on their ovaries at PG in comparison to the cows in the PO and POC protocols (P=0.03 and P=0.05, respectively). For all treatment protocols, the pregnancy rate of cows with >2 CLs on their ovaries at PG was significantly higher than for cows with ≤2 CLs on their ovaries at this time. The overall pregnancy rate for all cows studied was 42%. Separately, pregnancy rates for cows in PO, POC, and G6G protocols were calculated at 36.7%, 41.7%, and 47.3% respectively. The highest and the lowest pregnancy rates were obtained in the G6G and PO protocols, respectively (P=0.03). It can be concluded that the G6G protocol increased the pregnancy rate of cows in comparison to the PO but not to the POC protocol. This result can be attributed to the increase in serum concentration of P4 at GnRH1 and the greater number of CLs at PG following implementation of the G6G compared to the PO protocol. Although CIDR administration in the POC protocol led to an increase in the pregnancy rate of cows compared to the PO protocol, possibly by increasing the synchrony rate and the quality of the ovulatory follicle, this increase was not statistically significant (P=0.09).

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COMPARISON OF LONG-TERM PROGESTERONE-BASED PROTOCOL ON REPRODUCTIVE PERFORMANCE OF PREPUBERTAL AND PUBERTAL BEEF HEIFERS.

Archives of Veterinary Science ◽

10.5380/avs.v19i1.32805 ◽

2014 ◽

Vol 19 (1) ◽

Cited By ~ 1

Author(s):

Emanoel Faleiros Silveira ◽

Luiz Ernandes Kozicki ◽

Marcio Saporski Segui ◽

Romildo Romualdo Weiss ◽

Ivo Walter Santos ◽

...

Keyword(s):

Ultrasound Examination ◽

Prostaglandin F2α ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Estrus Synchronization ◽

Device Removal ◽

Timed Artificial Insemination ◽

Red Angus ◽

Natural Service

The aim of this study was to investigate estrus synchronization in prepubertal and pubertal heifers (crossbred ½ Nelore x Red Angus - commercial herd) submitted to a long-term progesterone-based protocol for timed artificial insemination (TAI), as well as overall pregnancy rates. Four hundred forty-seven heifers underwent ultrasound examination of the ovaries and were assigned to one of 3 groups: (1) prepubertal heifers (PPNS; n = 114) with ovarian follicles <8 mm in diameter and no corpus luteum (CL) that were submitted to natural service (NS) by bulls for 10 days; (2) prepubertal heifers (PPTAI; n = 124) with follicles <8 mm in diameter and no CL that underwent estrus synchronization with injection of 4.0 mg estradiol benzoate (EB) and insertion of a controlled-release intravaginal progesterone (P4) device containing 0.558 g P4 on d 0, followed by P4 device removal and injection of 150 mg prostaglandin F2α and 0.6 mg estradiol cypionate (ECP) on d 8, and TAI on d 10; and (3) pubertal heifers (PTAI; n = 209) with follicles >8 mm in diameter and/or a CL that underwent the same protocol as PPTAI heifers. Overall pregnancy rate was determined by transrectal ultrasonography on d 45 after NS or TAI. Data were analyzed using the FREQ procedure of SAS (SAS Inst. Inc., Cary, NC). Pregnancy rates were as follows: 20.1% in PPNS, 37.0% in PPTAI, and 48.5% in PTAI (P < 0.05). In conclusion, TAI after estrus synchronization with a hormonal protocol using EB and ECP in prepubertal and pubertal heifers resulted in higher pregnancy rates than prepubertal heifers exposed to natural service, and exposure of prepubertal heifers to a long-term progesterone-based protocol effectively synchronized estrus.

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Fertility parameters in German dairy herds: Associations with milk yield and herd size

Czech Journal of Animal Science ◽

10.17221/206/2019-cjas ◽

2019 ◽

Vol 64 (No. 11) ◽

pp. 459-464

Author(s):

Jörn Rethmeier ◽

Michael Wenzlau ◽

Martin Wagner ◽

Steffi Wiedemann ◽

Lisa Bachmann

Keyword(s):

Pregnancy Rate ◽

Milk Yield ◽

Reproductive Performance ◽

Dairy Farms ◽

Herd Size ◽

Pregnancy Rates ◽

Conception Rate ◽

Service Rate ◽

Dairy Herds ◽

Key Factor

Fertility in dairy cows has decreased over the last fifty years while milk production per cow has increased. Furthermore, dairy herds become larger resulting in fewer employees per cow, which might also influence reproductive performance. To elucidate the situation in Germany, selected parameters (conception rate, service rate, pregnancy rate, days to first insemination and days open) were studied using data on 148 herds. For statistical analysis the herds were categorized concerning milk yield: (1) < 30 kg, (2) 30‒35 kg, and (3) > 35 kg/cow/day as well as concerning herd size: (1) < 200, (2) 200‒400, (3) 400‒1000 and (4) > 1000 milking cows. There was no difference in conception rate among herds. That means on dairy farms of larger size or with high milk yield the chance of an inseminated cow to become pregnant is the same as in small herds or in herds with low milk yield. Small herds (< 200 cows) had lower pregnancy rates than larger herds (200–400 cows). The pregnancy rate in herds with different milk yield was not statistically different. Though there was a trend that dairy farms with higher milk yield (> 30 kg) had higher pregnancy rates. The statistical differences and trends of pregnancy rates are due to higher service rate in larger herds as well as in herds with high milk yield. Therefore, service rate is the key factor for high reproductive performance on dairy farms. Poor fertility is not associated with high milk yield on herd basis or large herd size but may represent inappropriate farm management.

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The influence of purified porcine relaxin on the reproductive performance of sows following artificial insemination with fresh or frozen semen

Canadian Journal of Animal Science ◽

10.4141/cjas91-027 ◽

1991 ◽

Vol 71 (1) ◽

pp. 237-239 ◽

Cited By ~ 1

Author(s):

P. A. Thacker ◽

A. D. Gooneratne ◽

R. N. Kirkwood

Keyword(s):

Key Words ◽

Pregnancy Rate ◽

Litter Size ◽

Reproductive Performance ◽

Artificial Insemination ◽

Pregnancy Rates ◽

Frozen Semen

Pregnancy rates and litter sizes following insemination of sows with fresh-extended and frozen-thawed semen averaged 71 vs. 53% and 10.6 vs. 4.4, respectively, and was not affected by the addition of 12.5 μg relaxin to semen. These results indicate no relaxin mediated effect on either pregnancy rate or litter size when sows are artificially inseminated with relaxin-supplemented semen. Key words: Artificial insemination, relaxin, sows

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206 EFFECTS OF A COMBINATION OF A PRID, PGF2α AND eCG, ON ESTRUS SYNCHRONIZATION AND PREGNANCY RATE FOLLOWING EMBRYO TRANSFER IN HOLSTEIN HEIFERS

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab206 ◽

2007 ◽

Vol 19 (1) ◽

pp. 220 ◽

Cited By ~ 3

Author(s):

Y. Aoyagi ◽

A. Ideta ◽

M. Matsui ◽

K. Hayama ◽

M. Urakawa ◽

...

Keyword(s):

Pregnancy Rate ◽

Embryo Transfer ◽

Plasma Concentrations ◽

Pregnancy Rates ◽

Bovine Embryo ◽

Estrus Synchronization ◽

Chi Square ◽

End Of Treatment ◽

Chi Square Analysis ◽

Day Of Embryo Transfer

Successful bovine embryo transfer requires synchronization of luteolysis, estrus and ovulation. The objective of the present study was to evaluate the effect of a combination of a PRID, PGF2� and eCG, on estrus synchronization and pregnancy rate in recipient heifers. A PRID� (ASKA Pharmaceutical Co., Ltd., Tokyo, Japan) was inserted into the vagina at random days of the estrous cycle for 7 (n = 35) or 9 (n = 43) days. Two days before removal of the PRID, the heifers were injected with PGF2� IM (2 mL Resipron�-C containing 0.25 mg mL-1 cloprostenol; ASKA). About half of the heifers in each group received 250 IU eCG IM (Serotropin�; ASKA) at the time of PRID removal. Blood was collected several times from the start of treatment for 7 (n = 9) or 9 (n = 9) days and on the day of embryo transfer by jugular venipuncture; plasma was immediately separated and stored at -20�C until assayed for plasma concentrations of estradiol-17α (E2) and progesterone (P4). The E2 and P4 determinations were performed by enzyme immunoassay after extraction by diethyl ether. Pregnancy was determined by ultrasonography on Day 30 (Day 0 = estrus). The rates of successful standing estrus (no. in estrus/PRID inserted), embryo transfer (no. transferred/estrus), and pregnancy (no. pregnancy/transferred) were compared between groups. Data were analyzed by chi-square analysis or Fisher's PLSD test following ANOVA. Injection of eCG at the time of PRID removal had no significant effect on the rates of successful standing estrus, embryo transfer, or pregnancy (P > 0.05). The proportion of heifers treated for 9 days that exhibited standing estrus (93&percnt;, 40/43) was significantly higher than the proportion of heifers treated for 7 days that exhibited standing estrus (66&percnt;, 23/35, P < 0.01). Of the heifers that were treated for 9 days, the proportion of heifers exhibiting standing estrus within 2 days after the end of treatment was significantly higher (93&percnt;, 37/40) than for heifers that were treated for 7 days (65&percnt;, 15/23; P < 0.01). Pregnancy rates of heifers treated for 9 days (84&percnt;, 32/38) and 7 days (81&percnt;, 17/21) were not significantly different. The E2 : P4 ratio normally increases during follicle growth and CL regression. The plasma E2 : P4 ratio between the time of injection of PGF2α and the time of PRID removal was significantly higher for heifers that were treated for 9 days than it was for heifers that were treated for 7 days (P < 0.01). These results suggest that a combination of PRID treatment for 9 days and injection of PGF2α 2 days before PRID removal successfully synchronized estrus in recipient heifers and led to high pregnancy rates following embryo transfer.

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29 SHORT-TERM v. LONG-TERM PROGESTERONE PROTOCOL USING CERVICAL OR INTRAUTERINE FIXED-TIME INSEMINATION IN SHEEP

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab29 ◽

2010 ◽

Vol 22 (1) ◽

pp. 172

Author(s):

A. Menchaca ◽

M. Vilariño ◽

E. Rubianes

Keyword(s):

New York ◽

Pregnancy Rate ◽

Body Condition Score ◽

Skim Milk ◽

Prostaglandin F2α ◽

Fixed Time ◽

Short Term ◽

Condition Score ◽

N 93

The short-term protocol with progesterone, prostaglandin F2α (PGF2α), and eCG is used to control follicular dynamics and luteal activity synchronizing the ovulation for fixed-time AI in sheep. The objective of this experiment was to compare the pregnancy rate obtained with short-term protocol (6 d) and long-term protocol (14 d) using cervical or intrauterine fixed-time AI in sheep. Three hundred fifty-two Merino ewes with a body condition score of 2.9 ± 0.3 (mean ± SD; scale 0 to 5) were used during the breeding season (April, 33S, Uruguay). All the females received a CIDR-G (0.3 g of progesterone, InterAg, Hamilton, New Zealand) for 6 d (short-term protocol; n = 178) or 14 d (long-term protocol, n = 174). One imdose of eCG (300 IU, Novormon, Syntex, BA, Argentina) was given at the moment of device withdrawal for the both protocols, and one imdose of PGF2α (10 mg of dinoprost, Lutalyse, Pfizer, New York, NY, USA) was given at the end of the short-term protocol to ensure luteolysis. Cervical AI (short-term protocol, n = 85; long-term protocol, n = 104) or intrauterine AI (short-term protocol, n = 93; long-term protocol, n = 70) was performed 48 or 54 h after device withdrawal, using 200 × 106 or 100 × 106 spermatozoa per ewe, respectively. Fresh semen was extended in UHT skim milk (1000 × 106 spermatozoa mL-1) and used within 1 h of collection. Estrus was recorded twice a day for 4 days after device withdrawal using vasectomized males. Pregnancy diagnosis was performed by transrectal ultrasonography 40 d after AI (5.0 MHz, Aloka, Tokyo, Japan). Logistic regression was used to analyze the effect of the treatment (P < 0.05), the AI technique (P < 0.05), and their interaction (P = NS). Pregnancy rate was higher for the short-term than for the long-term protocol, and for intrauterine than for cervical AI (Table 1). The highest pregnancy rate was achieved with short-term protocol using intrauterine AI (54.8%, 51/93), and the lowest response was obtained with long-term protocol using cervical AI (33.7%, 35/104; P < 0.05). These data were not different from data of short-term protocol using cervical AI or long-term protocol using intrauterine AI (42.4%, 36/85; and 44.3% 31/70, respectively). Ewes in estrus/treated ewes was not different among short-term and long-term protocols (83.7%, 149/178; and 82.8%, 144/174, respectively; P = NS). In summary, regardless of insemination technique, short-term protocol of 6 d enhances pregnancy rate in fixed-time AI programs in sheep. Table 1.Main effects of short-term (6 d) v. long-term (14 d) protocol using cervical or intrauterine fixed-time AI on pregnancy rate in sheep Financially supported by Pfizer, SP, Brazil.

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RESULT OF ADVANCED TECHNIQUES FOR ARTIFICIAL INSEMINATION IN EWES WITH FROZEN-THAWED SEMEN

Mongolian Journal of Agricultural Sciences ◽

10.5564/mjas.v13i2.513 ◽

2015 ◽

Vol 13 (2) ◽

pp. 43-47

Author(s):

P Myagmarsuren ◽

U Myagmardulam ◽

Ts Haliunaa

Keyword(s):

Pregnancy Rate ◽

Reproductive Performance ◽

Artificial Insemination ◽

Intrauterine Insemination ◽

Animal Husbandry ◽

Pregnancy Rates ◽

Luminal Diameter ◽

Physical Size ◽

Domestic Species ◽

Breeding Station

In all domestic species, acceptable pregnancy rate with frozen-thawed semen is 20-30% through simply cervical and vaginal insemination. Researchers have proved that achievable high results can be expected only from intrauterine insemination in ewes. Unlike the cow, and goat, the cervix of ewes is a formidable barrier to penetrate for transcervical intrauterine insemination. It is not only due to the physical size of the canal and a narrow luminal diameter (even at estrus), but also due to its caudally facing eccentric series of four to eight funnel-like rings. The major aim of this study was to evaluate a comparison of transcervical and laparoscopic intrauterine artificial insemination techniques with frozen –thawed semen on the reproductive performance of ewes.58ewes of 3-4 years of age, so called Altanbulag subspecies of breed were selected and equally divided into 2 groups for the AI methods from October 15-20, 2013 in the breeding station of Research Institute of Animal Husbandry in Hongor sum, Darhan uul province. The estrus was synchronized with EAZI-BREED TMCIDR in which the progesterone content was 0.3 g. After 12 days, the CIDR were removed, PMSG of 400 and 200 IU were administrated intramuscularly per ewe. The total success of synchronization rate was 93.3%. The results has shown the possibilities of laparoscopic and transcervical AI techniques in 55.17%, 41.37% (p>0.05) of pregnancy rates respectively, with frozen-thawed semen in ewes by ultrasonography diagnosis.Mongolian Journal of Agricultural Sciences Vol.13(2) 2014: 43-47

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