Presynchronization of lactating dairy cows with PGF 2α and GnRH simultaneously, 7 days before Ovsynch have similar outcomes compared to G6G

Yousuf, Muhammad; Martins, J.P.N.; Ahmad, Nasim; Nobis, Kerry; Pursley, J.R.

doi:10.1016/j.theriogenology.2016.05.021

Cited by 12 publications

(18 citation statements)

References 36 publications

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“…These programs manipulate follicle and CL development before the start of Ovsynch so that the first GnRH of Ovsynch causes ovulation of a first wave dominant follicle (Moreira et al, 2001;Peters and Pursley, 2002;Bello et al, 2006;Martins and Pursley, 2016). Fertility programs increase the likelihood of increased circulating P4 concentrations during growth of the ovulatory follicle due to the induction of an accessory CL induced in response to the first GnRH of Ovsynch (Bello et al, 2006;Martins et al, 2011aMartins et al, , 2017Pursley and Martins, 2011;Jimenez-Krassel et al, 2012;Yousuf et al, 2016). Increased P4 during growth of the ovulatory follicle was associated with increased fertility of dairy cows (Fonseca et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Level of circulating concentrations of progesterone during ovulatory follicle development affects timing of pregnancy loss in lactating dairy cows

Martins

Wang

et al. 2018

Journal of Dairy Science

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The objective of this experiment was to determine the effect of high versus low progesterone (P4) during the pre-dominance or dominance phase (or both) of ovulatory follicle development on follicular dynamics and fertility of lactating dairy cows. Progesterone (P4) was manipulated to reach high (H) or low (L) serum concentrations during the pre-dominance phase (d 0 to 4 of the wave) and dominance phase (d 5 to 7 of the wave) of a second follicular wave ovulatory follicle, creating 4 treatments: H/H, H/L, L/H, and L/L. Luteolysis was induced with PGF on d 7 of the wave and ovulation was induced with GnRH 56 h after PGF. Cows (n = 558) received artificial insemination (AI) 16 h following GnRH. Pregnancy was determined at 6 intervals during gestation and at calving to quantify pregnancy loss beginning at d 23 post-AI utilizing pregnancy-specific protein B (PSPB) in novel within-cow comparisons. Cows with single ovulations assigned to the L/L treatment had greater pre-ovulatory follicle diameter compared with cows assigned to the L/H or H/L treatments. Cows with single ovulations had greater pre-ovulatory follicle diameter compared with cows with double ovulations. Low P4 in H/L, L/H, and L/L increased double ovulation rate compared with H/H. Cows with double ovulations had greater pregnancies per AI (P/AI) on d 23 post-AI compared with cows with single ovulations but had greater losses if ovulations were unilateral. Cows with low P4 during the entire period of the ovulatory follicle development also had greater P/AI on d 23 post-AI compared with cows with high P4 during both phases. However, full-term P/AI was not different between treatments. This was a result of the greater incidence of pregnancy losses between d 35 and 56 of gestation for cows with unilateral double ovulations compared with bilateral double ovulations and single ovulatory cows. Cows with single ovulation and low circulating P4 during the dominance period of follicle development had increased pregnancy losses between d 35 and 56 of gestation compared with cows with single ovulations and high P4. The PSPB measurements on d 16 and 23 post-AI were highly accurate in the prediction of pregnancy at d 28. The PSPB differed on d 23 and 28 between cows that had versus cows that did not have pregnancy losses between d 28 and 35 of gestation. In summary, circulating concentrations of P4 during ovulatory follicle development affected numbers of follicles ovulated and timing of subsequent pregnancy losses.

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Section: Introductionmentioning

confidence: 99%

Level of circulating concentrations of progesterone during ovulatory follicle development affects timing of pregnancy loss in lactating dairy cows

Martins

Wang

et al. 2018

Journal of Dairy Science

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“…A similar synchronization protocol was previously designed for first inseminations after calving (Stevenson & Pulley, ). G6G was also originally designed for first artificial inseminations (Bello, Steibel, & Pursley, ), and the G6G protocol reproducibly achieves high conception rates at the first TAI ranging from 35% (Astiz & Fargas, ) to 57% (Yousuf, Martins, Ahmad, Nobis, & Pursley, ). This protocol causes a large proportion of cows being at the optimal stage of the cycle to initiate Ovsynch and improve most aspects of synchronization before or during the Ovsynch.…”

Section: Introductionmentioning

confidence: 99%

Resynchronization with the G6G protocol: A retrospective, observational study of second and later timed artificial inseminations on commercial dairy farms

Patrón

López-Helguera

Pesantez-Pacheco

et al. 2018

Reprod Domestic Animals

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We recorded conception rates and estimated pregnancy rates following second and later timed artificial inseminations (TAIs) after hormonal resynchronization on commercial dairy farms, using the so-called G6G protocol (PGF day-0; GnRH 2, 8 days; PGF 15, 16 days, GnRH 17 days; TAI 18 days), and the 5-day Ovsynch protocol or 5DO (GnRH day 0; PGF 5, 6 days; GnRH 7 days; TAI 8 days). In four farms, both protocols were implemented in parallel, and these 1,368 s and later TAIs were used for the protocols' comparison based on logistic regression (544 TAIs in primiparous; 824 in multiparous cows; 1,024 TAIs after G6G [600 TAIs in multiparous and 424 in primiparous]; 344 TAIs after 5DO [224 TAIs in multiparous and 120 in primiparous]; 280 TAIs during the hot season; 1,088 during the cool season). Conception rate (CR) was 31.7% ± 12.0% among all cows, 35.1% ± 10.7% among cows resynchronized with the G6G protocol and 21.8% ± 9.7% among cows resynchronized with the 5DO protocol (p < 0.0001). CR among all cows was lower during the hot season (19.3% ± 8.4%) than during the cool season (34.9% ± 10.6%; p < 0.0001), and similar seasonal results were observed with G6G protocols. Logistic regression showed significant effects on CR in second and later TAIs by protocol (OR = 0.514; 95% CI 0.385-0.686; p < 0.0001) and season (OR = 0.486; 95% CI 0.350-0.676; p < 0.0001). Parity did not influence CR after second and later TAIs (p > 0.1), and no interaction with season or resynchronization protocol was found. Estimated pregnancy rates based on these CR data from both hormonal protocols suggest that G6G can be effectively used for second and later TAIs and highlight the importance of considering protocol and season when designing strategies for second and later timed AIs on dairy farms.

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“…Stwierdzono także, że poziom progesteronu w momencie podania prostaglandyny w programie OvSynch był wyższy w grupie pierwszej niż drugiej (5,75 wobec 4,64 ng/ml). Ostatecznie uznano, że jednoczesne podanie prostaglandyny i GnRH siedem dni przed startem programu OvSynch może być prostą alternatywą dla programu G6G zapewniającą akceptowalne rezultaty (61).…”

Section: Programy G6g I G7gunclassified

OvSynch program, its modifications and alternative hormonal programs in cow reproduction

Jaśkowski

Herudzińska

Kulus

et al. 2018

Medycyna Weterynaryjna

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The OvSynch program was formulated over 20 years ago (it consists in administering gonadoliberin on the day of starting the procedure, then injecting prostaglandin 7 days after the GnRH initial injection, and administration of GnRH two days after applying PGF2α. The procedure ends in the insemination of a female 16–20 hours after administering the final dose of the hormone) and it is commonly applied in cow reproduction management protocols. It has evolved into numerous modifications which has boosted its effectiveness. They have consisted in replacing GnRH with hCG or pLH, diversifying the time of the final injection of GnRH, which follows the prostaglandin injection, and postponing insemination after the final GnRH dose, as well as changing the dosage of the aforementioned hormones. To expedite the Ovsynch protocol, so-called PreSynch was used, which involved administering two prostaglandin injections with a 14 day interval before applying the initial GnRH dose in protocol OvSynch. The interval between the second prostaglandin injection in the PreSynch program varied (PreSynch-14, PreSynch-12, PreSynch-11, PreSynch-11 and PreSynch). The pregnancy rate can be also improved by introducing GnRH injection before starting the OvSynch program, administered 7, 6 or 4 days before the initial GnRH injection in OvSynch (G7G, G6G, G4G). Higher pregnancy rates, in comparison to the PreSynch-OvSynch program, can be obtained by applying the DoubleOvsynch protocol. In this protocol two OvSynch programs are administered in a 7-day interval. Lately, alternative programs such as DoubleSynch and EstraDoubleSynch have emerged. The DoubleSynch protocol consists in administering PGF2α in day 0, GnRH on the second day, another PGF application on the 9th day, and the second GnRH dose on the 11th day. Artificial insemination is performed in oriented time (TAI). This solution is used in order to achieve a higher percentage of pregnant cows in comparison to the PreSynch+OvSynch protocol. It also enables synchronisation of heat and ovulation, both after the first and the second hormonal treatment of GnRH. In EstraDoubleSynch protocol the second injection of GnRH at the end of the DoubleSynch program is replaced by estradiol benzoate (BE) administration on the 10th day, in order to acquire a higher level of follicle waves synchronisation and ovulation rate. Those programs applied in cow reproduction management can positively influence fertility and boost cow breeding profitability..

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Presynchronization of lactating dairy cows with PGF 2α and GnRH simultaneously, 7 days before Ovsynch have similar outcomes compared to G6G

Cited by 12 publications

References 36 publications

Level of circulating concentrations of progesterone during ovulatory follicle development affects timing of pregnancy loss in lactating dairy cows

Level of circulating concentrations of progesterone during ovulatory follicle development affects timing of pregnancy loss in lactating dairy cows

Resynchronization with the G6G protocol: A retrospective, observational study of second and later timed artificial inseminations on commercial dairy farms

OvSynch program, its modifications and alternative hormonal programs in cow reproduction

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