Synchronization rate, size of the ovulatory follicle, and pregnancy rate after synchronization of ovulation beginning on different days of the estrous cycle in lactating dairy cows

Vasconcelos, José Luiz Moraes; Silcox, R.W.; Rosa, Guilherme J. M.; Pursley, J.R.; Wiltbank, Milo C.

doi:10.1016/s0093-691x(99)00195-8

Cited by 507 publications

(525 citation statements)

References 39 publications

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“…A greater percentage of cows were time inseminated in OVS between 16-24 h after the second GnRH injection, while 9.7% of those cows showed oestrus after that time and were re-inseminated to maximise the pregnancy rate. These cows likely initiated growth of a new follicular wave in response to ovulation of a dominant follicle; however, the follicle grows quickly and loses dominance during the nine-day interval between GnRH injections and failed to ovulate after the second GnRH injection [10]. Therefore, only 82.2% of the cows were synchronised, which agrees with the results of [10,19].…”

Section: Discussionsupporting

confidence: 75%

“…Stevenson et al [9] reported that 8 to 16% of cows showed oestrus in the OVS protocol around the time of PGF 2α injection. According to Vasconcelos et al [10] these cows failed to ovulate after the first GnRH injection; they were primarily in the second half of the oestrous cycle when they received the first GnRH injection and exhibited oestrus before the second GnRH injection because the corpus luteum regressed and the cows naturally came into oestrus. A greater percentage of cows were time inseminated in OVS between 16-24 h after the second GnRH injection, while 9.7% of those cows showed oestrus after that time and were re-inseminated to maximise the pregnancy rate.…”

Section: Discussionmentioning

confidence: 99%

“…These cows likely initiated growth of a new follicular wave in response to ovulation of a dominant follicle; however, the follicle grows quickly and loses dominance during the nine-day interval between GnRH injections and failed to ovulate after the second GnRH injection [10]. Therefore, only 82.2% of the cows were synchronised, which agrees with the results of [10,19]. Recently, Cartmill et al [20,21] reported that 83.8% of the cows were cycling in the OVS program, while 5 to 15% of the cows were not cycling at the time of insemination.…”

Section: Discussionmentioning

confidence: 99%

“…Treated cows are time inseminated at approximately 16 h after the last injection of GnRH without the need for oestrus detection. The ability of GnRH-PGF 2α based protocols to effectively synchronise oestrus and (or) ovulation is dependent upon the stage of follicular development at the time of initial GnRH injection; cows that started Ovsynch on d 5 to 13 had a higher probability of pregnancy and ended to have a lower rate of pregnancy loss than cows started at other stages [10].…”

Section: Introductionmentioning

confidence: 99%

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Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows

Alnimer

2005

Reprod. Nutr. Dev.

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-A total of 226 out of 245 postpartum lactating dairy cows in a commercial dairy farm were allocated to two groups of oestrous synchronisation protocols in order to evaluate reproductive performance. One group was treated with oestradiol benzoate (ODB) and PGF 2α on day 10 of the oestrous cycle with insemination at the detected oestrus, the second group underwent the Ovsynch (OVS) protocol (GnRH + PGF 2α + GnRH) with timed AI. Pregnancy was diagnosed by ultrasonography on day 28 after AI and confirmed by rectal palpation on day 45. A higher (P < 0.001) proportion of cows in OVS (100%) were inseminated within (19.2 ± 3.8 h) following the second GnRH injection than those of cows in EPE (ODB + PGF 2α + ODB) (70.6%) inseminated at the detected oestrus within (35.6 ± 5.2 h) following the second ODB injection. Pregnancy rates for the first AI at day 28 (64.0 ± 4.6, 62.4 ± 5.5%) and at day 45 post-insemination (40.4 ± 4.7, 40.0 ± 5.6%) for OVS and EPE cows respectively, did not differ between the two treatments, whereas, the overall pregnancy rates tended to be higher (P < 0.08) for the OVS (85.1 ± 3.8%) cows than the EPE cows (74.1 ± 4.5%). No differences were observed in pregnancy rates for first AI and overall up to fourth AI between primiparous (34.7 ± 5.8 and 85.3 ± 4.7%) and multiparous cows (43.5 ± 4.5 and 77.4 ± 3.6%). Days open for pregnant cows tended to be lower (P < 0.08) for OVS (76.2 ± 3) than for EPE cows (84.7 ± 4), while days open were higher (P < 0.05) in primiparous cows (85.3 ± 4) than in multiparous cows (75.6 ± 3). The results indicate that pregnancy rates for first AI were similar, but overall pregnancy rates up to the fourth AI tended to be higher for OVS than EPE cows, while days open was tended to be lower for OVS than EPE cows. dairy cows / oestrus-synchronisation / GnRH / oestradiol / PG / reproductive performance

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows

Alnimer

2005

Reprod. Nutr. Dev.

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“…Entretanto, este último estudo não incluiu um grupo-controle, inseminado no cio natural ou induzido, além de ter utilizado unicamente novilhas. Sabe-se que essa categoria de animais apresenta menor resposta ao protocolo Ovsynch, resultando em taxas de ovulação, após a primeira injeção de GnRH, da ordem de 50% (Martinez et al, 1999), ao passo que em vacas esse índice varia de 64% (Vasconcelos et al, 1999) a 90% (Pursley et al, 1995).…”

Section: Resultsunclassified

Eficácia do tratamento Ovsynch associado à inseminação artificial prefixada em rebanhos Bos taurus e Bos indicus

Alvarez

Martinez

Carvalho

et al. 2003

Pesq. agropec. bras.

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Resumo -O presente trabalho objetivou avaliar a eficácia do tratamento Ovsynch associado à inseminação artificial em tempo prefixado em vacas Bos taurus e Bos indicus. Foram utilizados rebanhos das raças Holandesa, Caracu, Nelore e Mantiqueira. Também foi incluído um rebanho de vacas Gir, com problemas de fertilidade. Cada rebanho foi dividido em três grupos. O grupo 1 recebeu o tratamento Ovsynch e foi inseminado em tempo prefixado. O grupo 2 foi inseminado no cio induzido com cloprostenol. O grupo 3 foi inseminado no cio natural. As taxas de concepção e de prenhez foram determinadas por ultra-sonografia. Não existiu interação significativa das variáveis reprodutivas analisadas para rebanho, idade, período pós-parto, número de parição e presença do bezerro. A taxa de concepção não diferiu (P>0,05) entre os grupos, ao passo que a taxa de prenhez foi superior (P<0,05) nos grupos 1 e 2 em comparação ao grupo 3. No rebanho Gir, o tratamento Ovsynch não alterou a taxa de concepção nem a de prenhez. Independentemente da raça, os tratamentos Ovsynch e cloprostenol não afetam a taxa de concepção, mas melhoram a taxa de prenhez. O tratamento Ovsynch não aumenta a fertilidade de vacas com problemas reprodutivos inespecíficos.Termos para indexação: gado bovino, reprodutividade, ovulação, sincronização, fertilidade. Efficacy of the Ovsynch treatment associated to fixed-time artificial insemination in Bos taurus and Bos indicus herdsAbstract -The present study aimed to evaluate the efficiency of Ovsynch treatment associated with prefixed-time artificial insemination on Bos taurus and Bos indicus cows. Herds of Holstein, Caracu, Nelore and Mantiqueira breeds were used. A herd of Gir cows with poor reproductive performance was also included. Each breed was divided in tree groups. Group 1 received Ovsynch treatment and was inseminated at prefixed time. Group 2 was induced to estrus with cloprostenol and inseminated thereafter. Group 3 was inseminated at natural heat. Conception and pregnancy rates were determined by ultra-sound. No significant interactions were detected among breeds, age, parity, postpartum period and lactating cows with or without their calves. Conception rates did not differ (P>0.05) among groups while pregnancy rate was higher (P<0.05) for group 1 and 2 comparing to group 3. In the Gir herd Ovsynch treatment did not enhance conception nor pregnancy rates. Independently of breed, conception rate is similar after Ovsynch, cloprostenol and control treatments, and pregnancy rate can be improved with Ovsynch and cloprostenol treatments. In cows with unspecific reproductive ovarian disorders, Ovsynch treatment do not enhance conception or pregnancy rates.

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Reproductive Management of Lactating Dairy Cows for First Postpartum Insemination

Santos

2011

Dairy Production Medicine

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Implementation of systematic breeding programs for fi rst postpartum insemination in dairy herds have become an integral part of the reproductive management of dairy cows, and they have allowed for increased insemination rates without compromising fertility. It is known that the fi rst 3 weeks past the end of the voluntary waiting period corresponds to the estrous cycle of greatest impact on reproduction of dairy herds. Therefore, assuring high pregnancy rate in this period is critical to optimize reproduction of dairy cows. This is related to the economic value of a pregnancy that is infl uenced by the day postpartum when the cow becomes pregnant, the need to manage large groups of cows without creating systems that might not be implemented due to diffi culty or lack of compliance, and the need to address defi ciencies in cow fertility such as poor estrous expression and detection.

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Synchronization rate, size of the ovulatory follicle, and pregnancy rate after synchronization of ovulation beginning on different days of the estrous cycle in lactating dairy cows

Cited by 507 publications

References 39 publications

Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows

Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows

Eficácia do tratamento Ovsynch associado à inseminação artificial prefixada em rebanhos Bos taurus e Bos indicus

Reproductive Management of Lactating Dairy Cows for First Postpartum Insemination

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