Use of medroxyprogesterone acetate (MAP) in lactating Holstein cows within an Ovsynch protocol: follicular growth and hormonal patterns

Cavestany, D.; Meikle, A.; Kindahl, H.; Lier, E. van; Moreira, F; Thatcher, W.W.; Forsberg, M.

doi:10.1016/s0093-691x(02)01230-x

Cited by 6 publications

(10 citation statements)

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“…Bello, et al [26] reported that the ovulatory follicle diameter was 15.7 ± 0.4 mm at the time of second GnRH injection of Ovsynch. In agreement with previous findings [16,25,26] the present study demonstrated that usage of half dose buserelin acetate for Ovsynch protocol in lactating cows did not have adverse effects on dominant follicle diameters.…”

Section: Discussionsupporting

confidence: 93%

“…Cavestany, et al [25] stated that the largest size of DF of the new wave was attained at the day of second GnRH and the diameter of DF on Day 9 was 16.2 ± 1.9 mm in cows treated with an Ovsynch protocol with medroxyprogesterone acetate. In a previous study [16] it was reported that DF diameter was 15.9 mm at 80 h after PGF injection of Ovsynch in lactating dairy cows.…”

Section: Discussionmentioning

confidence: 99%

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2016

Animal Review

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

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2016

Animal Review

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“…In Experiment 1, we demonstrated that MAP at a dose of 250 mg alone is incapable of blocking follicular growth, whereas at the higher dose of MAP, the dominant follicle failed to reach its normal size. These data agree with earlier studies, in which 300mg MAP failed to alter the growth of the dominant follicle (Cavestany et al 2003), or where rising concentrations of the synthetic progestin norgestomet inhibited growth of the dominant follicle (Sanchez et al 1995).…”

Section: Discussionsupporting

confidence: 92%

“…Medroxyprogesterone acetate (MAP) is cheaper than natural progesterone and is a potentially good option for extensive farming practices in Brazil. MAP has been used to induce estrus in post-partum beef cattle (Medeiros Bastos et al 2004, Terra et al 2008, and its use in synchronization of cyclic cattle within an Ovsynch protocol has been reported (Cavestany et al 2003, Terra et al 2008. Depending on stage of cycle, the dominant follicle subject to exposure to MAP may be the follicle that ovulates at MAP withdrawal (Burke et al 1996), therefore the impact of MAP synchronization protocols on follicle dynamics requires elucidation.…”

Section: Introductionmentioning

confidence: 99%

Effect of medroxy-progesterone acetate on follicular growth and endometrial cycloxygenase-2 (COX-2) expression during the bovine estrous cycle

et al. 2010

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RESUMO.-[Efeito do acetato de medroxi-progesterona sobre o crescimento filicular e expressão endometrial de ciclooxigenase-2 (COX-2) durante o ciclo estral de bovinos.] Este estudo teve como objetivo avaliar o efeito do acetato de medroxi-progesterona (MAP) com ou sem benzoato de estradiol (BE) sobre o crescimento folicular durante o ciclo estral bovino. No primeiro experimento, vacas da raça Hereford foram sincronizadas com um aná-logo sintético de PGF2á e tratadas com duas doses diferentes de MAP (250 ou 500mg), com ou sem EB, durante 7 dias, iniciando-se no oitavo dia do ciclo estral. Observou-se uma inibição do crescimento folicular (P<0,05) em todas as vacas, exceto no grupo controle e no grupo que recebeu 250mg de MAP sem BE. Os 75% dos animais não exibiu estro no momento da remoção do MAP, mas sim nos dias 21 e 22 do ciclo, demonstrando que os tratamentos não induziram cio. Para se determinar se o tratamento com BE alterou a sensibilidade endometrial à ocitocina e, assim, a cascata luteolítica, vacas multíparas The objective of this study was to evaluate the effect of medroxy-progesterone acetate (MAP) with or without estradiol benzoate (EB) on follicular growth during the estrous cycle in cattle. In the first experiment, Hereford cows were synchronized with a synthetic analogue of PGF 2 alpha and were treated with two different doses of MAP (250 or 500 mg) with or without EB for 7 days starting on day 8 of the estrous cycle. Follicular growth was inhibited (P<0.05) in all cows except controls and those receiving 250mg MAP without EB. Seventyfive percent of the animals (15/20) showed estrus on days 21 and 22 of the cycle rather than at MAP withdrawal, demonstrating that these treatments did not induce estrus. To determine whether the EB treatment altered endometrial sensitivity to oxytocin and thus the luteolytic cascade, multiparous pre-synchronized cows received 5 mg of EB followed 6 hours later with 50 IU of oxytocin (OT; n=9). Eight hours after EB injection, endometrial fragments were collected from the cows on days 4, 13 and 17 of the estrous cycle and COX-2 gene expression was measured by PCR. EB increased COX-2 mRNA levels only on day 17 of the estrous cycle (P<0.05). In conclusion, MAP alone or associated with EB is able to suppress bovine follicular growth. However, EB in the presence of MAP is not efficient to induce luteolysis in cows when injected on day 8 of the estrous cycle.

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“…PATTERSON & CORAH (1992) observaram este efeito administrando MGA a novilhas pré-púberes. O principal objetivo de um bom manejo reprodutivo é obter-se o número máximo de vacas prênhes no mais curto período de tempo possível (CAVESTANY et al, 2003). O manejo com sincronização dos estros, conforme indicam os resultados obtidos no presente experimento, foi capaz de induzir a uma concentração significativa das parições no início da temporada reprodutiva, o que resultou em um índice de repetição de crias significativamente superior nas fêmeas submetidas à sincronização e à indução de estros na primeira temporada de reprodução.…”

Section: Discussionunclassified