Effect of hCG vs. GnRH at the beginning of the Ovsynch on first ovulation and conception rates in cyclic lactating dairy cows

Keskin, Ahmet; Yılmazbaş-Meci̇toğlu, G.; Gümen, Ahmet; Karakaya, Ebru; Darici, R.; Okut, Hayrettin

doi:10.1016/j.theriogenology.2010.03.009

Cited by 46 publications

(52 citation statements)

References 24 publications

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“…Synchronisation rates in previous studies were between 75% and 95% (Bello et al, 2006;Brusveen et al, 2009;Galvao and Santos, 2010;Keskin et al, 2010). Similarly, in the current study, synchronisation rates ranged from 87% to 97%.…”

Section: Discussionsupporting

confidence: 77%

“…The success of the Ovsynch protocol dramatically depends on the responses to the hormones used in the protocol. With respect to the response to GnRH administrations, fertility is better in cows that respond to the GnRH-1 in the Ovsynch protocol compared to those cows that not respond (Vasconcelos et al, 1999;Moreira et al, 2001;Bello et al, 2006;Galvao and Santos, 2010;Keskin et al, 2010). In recent studies, the ovulatory response to GnRH-1 was between 45% and 75% (Bello et al, 2006;Galvao and Santos, 2010;Keskin et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Our results showed a numerical increase (7%) in response to GnRH-1 in the OVS-6CIDR group and that the administration of exogenous progesterone one day after GnRH-1 did not increase the response to GnRH-1 in cyclic lactating dairy cows. In most of the studies (Vasconcelos et al, 1999;Moreira et al, 2001;Bello et al, 2006;Galvao and Santos, 2010;Keskin et al, 2010), higher ovulation rates to GnRH-1 increase synchronisation rate (response to GnRH-2) and pregnancy rate in lactating dairy cows because of its positive effect on both luteal and follicular responses to subsequent PGF 2α and GnRH-2 treatments of the Ovsynch protocol. Similar to previous studies (Vasconcelos et al, 1999;Moreira et al, 2001;Bello et al, 2006;Keskin et al, 2010), cows that responded to GnRH-1 had a higher (P = 0.005) synchronisation rate (response to GnRH-2) compared to cows that did not respond, regardless of the treatments in our study.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of synchronisation and fertility after different modifications of the ovsynch protocol in cyclic dairy cows

Yılmazbaş-Meci̇toğlu

Karakaya

Keskin

et al. 2014

Acta Veterinaria Hungarica

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The objectives of this study were to evaluate the effects of (1) double doses of PGF 2α administration or (2) an exogenous progesterone (CIDR) applied concurrently with, or (3) the day after, first GnRH of Ovsynch (GnRH-1), on synchronisation and fertility during the Ovsynch protocol. All cows (n = 378) received the Ovsynch protocol (GnRH-7d-PGF 2α -56h-GnRH-18h-TAI). The 'OVS' group (n = 105) received only the Ovsynch protocol. The 'OVS-PGF' group (n = 118, GnRH-7d-PGF 2α -12h-PGF 2α -44h-GnRH-18h-TAI) received an extra dose of PGF 2α 12 h later on Day 7. The 'OVS-7CIDR' group (n = 78, GnRH+CIDR-7d-PGF 2α -56h-GnRH-18h-TAI) received a CIDR for 7 days between GnRH-1 and PGF 2α . In the 'OVS-6CIDR' group (n = 77, GnRH-24h-CIDR-6d-PGF 2α -56h-GnRH-18h-TAI), CIDR was applied one day after GnRH-1 and removed 6 days later. When all cows were evaluated, the responses to GnRH-2 were higher (P = 0.005) in cows that responded to GnRH-1 (95.4%) compared to the cows that did not respond (87.6%). The pregnancy rates at 31 and 62 days for each group were 48.6% and 42.9% in the OVS, 54.2% and 52.5% in the OVS-PGF, 52.6% and 48.7% in the OVS-7CIDR, and 55.8% and 49.3% in the OVS-6CIDR groups. Thus, none of the three different treatments has an effect on increasing the outcomes of the Ovsynch protocol in cyclic lactating dairy cows.

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Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of synchronisation and fertility after different modifications of the ovsynch protocol in cyclic dairy cows

Yılmazbaş-Meci̇toğlu

Karakaya

Keskin

et al. 2014

Acta Veterinaria Hungarica

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“…These results showed that ovulatory follicle size at TAI is affected not only by hormonal interactions during the estrous cycle (2,28) and hormonal treatments for synchronization (6,(9)(10)(11)19,29), but also by other factors such as parity (8), milk production (5,30), season, and breed. For instance, milk production has been correlated with an increase in the size of the ovulatory follicle.…”

Section: Discussionmentioning

confidence: 99%

“…Some studies have shown that larger ovulatory follicles at the time of AI increased pregnancy per AI (P/AI) (6,7,(9)(10)(11)(12)(13)(14)(15)19,20). These studies indicated that larger follicles were associated with higher estradiol and progesterone levels and a larger CL.…”

Section: Introductionmentioning

confidence: 99%

The effect of ovulatory follicle size at the time of insemination onpregnancy rate in lactating dairy cows

Keskin

Mecitoğlu²,

Karakaya‐Bilen³

et al. 2016

Turk J Vet Anim Sci

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The aims of this study were to determine the factors that affect follicle size at the time of artificial insemination (AI) and to detect the relationship between ovulatory follicle size at the time of AI and pregnancy rate in dairy cows. A total of 1428 follicle size measurements were obtained from Holstein-Friesian (HF) and Swedish Red (SR) cows that were inseminated with the fixed-timed AI protocols used in this study. Follicle size was affected by breed (P = 0.0001), milk production (P = 0.01), parity (P = 0.05), and season (P = 0.04). Follicle size was greater (P = 0.0001) in the HF (15.55 mm) than the SR cows (14.88 mm). Multiparous cows had larger (P = 0.04) follicles (15.35 mm) than the primiparous cows (15.07 mm). Cows with follicle sizes between 13.5 and 17.5 mm were more likely to be pregnant than cows with other sizes follicles (P < 0.01). Embryonic loss was lower (P < 0.01) in cows with follicle sizes between 13.5 and 16.5 mm. Thus, the follicle size was affected by breed, milk production, parity, and season. Pregnancy and embryonic loss in lactating dairy cows were significantly related to follicle size.

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Synchronization of ovulation with human chorionic gonadotropin in lactating dairy cows with ovarian cysts during heat stress

Navanukraw

Khanthusaeng

Kraisoon

et al. 2015

Trop Anim Health Prod

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A study was conducted during hot season to determine the effect of synchronization of ovulation with human chorionic gonadotropin (hCG) on fertility of lactating dairy cows with ovarian cysts. Non cyclic Holstein dairy cows (n = 80) were stratified by parity and diagnosed as having an ovarian cyst. The cows were further identified as follicular or luteal cysts according to the plasma progesterone (P4) concentration and the cystic image of ultrasonography. Cystic cows were randomly assigned to receive treatments (Ovsynch as the control or Ovsynch plus 3000 IU hCG). All cows were artificially inseminated at 16-18 h after the second gonadotropin releasing hormone injection. Cows supplemented with hCG had a greater number of corpus luteum (1.8 ± 0.2 and 0.8 ± 0.3; P < 0.05) and had greater P4 concentration on day 12 than those control cows (6.3 ± 0.3 and 3.9 ± 0.4 ng/ml; P < 0.05). Concentration of cortisol did not differ between groups of cystic cows. No significant differences were found in overall conception rates between the treatments; however, significantly greater conception rate (P = 0.03) was observed in cows with luteal cysts receiving Ovsynch plus hCG. This study highlights that administration of hCG following the Ovsynch-based timed artificial insemination (AI) is more effective than the control Ovsynch by which the hCG affects corpus luteum (CL) development, P4 concentration, and thus improves conception rate in dairy cows with luteal cysts.

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Effect of hCG vs. GnRH at the beginning of the Ovsynch on first ovulation and conception rates in cyclic lactating dairy cows

Cited by 46 publications

References 24 publications

Comparison of synchronisation and fertility after different modifications of the ovsynch protocol in cyclic dairy cows

Comparison of synchronisation and fertility after different modifications of the ovsynch protocol in cyclic dairy cows

The effect of ovulatory follicle size at the time of insemination onpregnancy rate in lactating dairy cows

Synchronization of ovulation with human chorionic gonadotropin in lactating dairy cows with ovarian cysts during heat stress

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