Response of dairy heifers to Prostaglandin F2α after treatment with human chorionic gonadotropin1

Shipley, S.K.; Fuquay, John W.; Smith, Andrew C.; Stuart, M J

doi:10.1016/s0093-691x(88)80018-9

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…Treatment of cows with 1000 iu hCG on day 7 or 14 after insemination resulted in increased plasma progesterone. Such increases after hCG treatment at different stages of the oestrous cycle have been reported by others (Mason et al, 1962;Edquin & Sequin, 1982;Shipley et al, 1988;Breuel et al, 1990). The increased progesterone synthesis could have resulted from hypertrophy of luteal cells in the spontaneous corpora lutea (Veenhuizen et al, 1972;Helmer & Britt, 1986) and from formation of accessory corpora lutea.…”

Section: Discussionsupporting

confidence: 77%

Effect of human chorionic gonadotrophin on dominant follicles in cows: formation of accessory corpora lutea, progesterone production and pregnancy rates

Rajamahendran¹,

Sianangama²

1992

Reproduction

114

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Thirty-four lactating Holstein cows were randomly assigned to four groups for treatment with human chorionic gonadotrophin (hCG, 1000 iu) at insemination day 0 (n = 8) or 7 (n = 9) or 14 days (n = 9) after insemination or with no hCG treatment (control, n = 8). Ultrasound imaging of the ovaries and plasma progesterone measurements were carried out to determine follicular dynamics and corpus luteum growth and function. Rates of formation of accessory corpora lutea were higher among cows treated on days 0 (three cows), 7 (seven cows) or 14 (four cows) than in the controls (one cow). Total corpus luteum diameter was greater (P less than 0.01) among hCG-treated cows than in controls 7-42 days after insemination. Concentrations of progesterone in plasma were significantly (P less than 0.05) higher in cows treated with hCG on days 7 or 14 than in those treated on day 0 or in controls, at days 18, 35 or 42 after insemination. Seven of the cows treated on day 7 became pregnant, whereas four, four and three cows treated on days 0 or 14 and control cows became pregnant, respectively. The results suggest that hCG treatment at 7 days after insemination could be used to produce accessory corpora lutea, raise plasma progesterone concentration and hence reduce the incidence of early embryonic mortality in cattle.

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Section: Discussionsupporting

confidence: 77%

Effect of human chorionic gonadotrophin on dominant follicles in cows: formation of accessory corpora lutea, progesterone production and pregnancy rates

Rajamahendran¹,

Sianangama²

1992

Reproduction

114

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“…Estas observações, também, foram feitas por SHIPLEY et al (1988) e BREUEL et al (1988. Não obstante, em virtude de o efeito luteotrópico do hCG sobre o corpo lúteo aumentar a proporção de células luteais grandes e por estas possuírem maior proporção de receptores para PGF 2 α (NISWENDER et al, 1985), aumentando, assim, o potencial para sensibilidade a esse luteolítico (SIANANGAMA e RAJAMAHEDRAN, 1996), no presente estudo, não houve diferença na taxa de sincronização de estro entre os animais dos tratamentos, provavelmente, por causa do pequeno número de animais utilizados (Tabela 2).…”

Section: Resultsunclassified

“…Administrado por via intramuscular, esse hormônio persiste por longo período no organismo animal, sendo detectado no plasma sangüíneo de novilhas 66 horas após sua aplicação (SCHMITT et al, 1996 a). Na fase luteal do ciclo estral, aumenta a concentração sérica de progesterona (HELMER e BRITT, 1987;SHIPLEY et al, 1988) e prolonga a duração do ciclo estral por, aproximadamente, cinco dias (EDUVIE e SEGUIN, 1982;MACMILLAN et al, 1986). Por sua vez, tratamentos antes do dia 7 ou depois do dia 17 do ciclo estral não influem na duração desse ciclo (HELMER e BRITT, 1986).…”

Section: Introductionunclassified

Sincronização da onda folicular com hCG prévia à indução da luteólise com cloprostenol em bovinos

Torres¹,

Angulo²,

Junqueira³

et al. 1999

R. Bras. Zootec.

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O efeito da aplicação de diferentes doses de hCG sobre a emergência de nova onda de crescimento folicular e o número de folículos recrutados dessa onda, a formação de corpo lúteo acessório, o diâmetro do folículo dominante e do corpo lúteo espontâneo no dia da aplicação do luteolítico, a subseqüente taxa de sincronização e o intervalo da aplicação de PGF2α à manifestação do estro foram avaliados. Vinte fêmeas bovinas mestiças em diestro, divididas em quatro tratamentos, contendo cinco animais cada, foram usadas. No tratamento 1, os animais receberam 500 UI I.M. hCG no dia 0, dia em que se iniciou o tratamento, e 150 μg D(+) cloprostenol no dia 6; já nos tratamentos 2, 3 e 4, receberam, respectivamente, 1000, 2000 e 3000 UI hCG, pela mesma via de aplicação, e 150 μg D(+) cloprostenol no dia 6. A atividade ovariana foi monitorada diariamente, com auxílio do aparelho de ultra-sonografia, do dia 0 ao estro, ou até o dia 11 após o tratamento, nos animais que não responderam à prostaglandina. Não houve diferença entre os efeitos de 500, 1000, 2000 e 3000 UI hCG sobre a dinâmica folicular, a taxa de sincronização e o intervalo da aplicação de PGF2α ao estro. Houve, no entanto, tendência de as dosagens de 2000 e 3000 UI induzirem à emergência de nova onda de crescimento folicular mais rapidamente que 500 ou 1000 UI destes hormônios.

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“…Exogenous hCG increases P4 synthesis (Mason et al, 1962;Veenhuizen et al, 1972;Eduvie and Seguin, 1982;Helmet andBritt, 1986, 1987;Shipley et al, 1988). Administration of hCG postbreeding has been reported to increase (Brown et al, 1973) or have no effect (Hansel et al, 1976;Echtemkamp and Maurer, 1983) on pregnancy rate.…”

mentioning

confidence: 99%

Systemic Progesterone Concentration Following Human Chorionic Gonadotropin Administration at Various Times during the Estrous Cycle in Beef Heifers

Breuel

Spitzer

Henricks

1989

Journal of Animal Science

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In Trial 1, 26 heifers were allotted randomly to a control group or one of four groups to receive a single injection of 3,000 IU hCG on d 1, 4, 7 or 10 of an estrous cycle. Heifers next completed a nontreated cycle, and at their third estrus were reallotted to one of the five groups described previously. Estrous cycle length was extended in cycle 1 but was not altered during the nontreated cycle or in cycle 3. Administration of hCG on d 4 or 7 increased (P less than .05) mean serum progesterone (P4) over the first 16 d of the estrous cycle by .9 and .8 ng/ml, respectively. In Trial 2, 23 heifers were allotted randomly to one of two groups to receive a placebo or a single injection of 3,000 IU hCG on d 4 of an estrous cycle. Heifers were inseminated artificially at subsequent estrus. On d 4 postbreeding, treatments were repeated. Administration of hCG on d 4 of the prebreeding estrous cycle increased (P less than .05) mean P4 over the first 16 d by .9 ng/ml, whereas mean P4 over the first 16 d postbreeding was not affected by a second injection of hCG on d 4 postbreeding. Administration of hCG increased (P less than .05) first-service pregnancy rate (92 vs 55%). In conclusion, progesterone concentrations were enhanced by hCG given on d 4 or 7 of the estrous cycle, and pregnancy rate was increased when hCG was administered both on d 4 of the prebreeding cycle and d 4 postmating.

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Response of dairy heifers to Prostaglandin F2α after treatment with human chorionic gonadotropin1

Cited by 10 publications

References 16 publications

Effect of human chorionic gonadotrophin on dominant follicles in cows: formation of accessory corpora lutea, progesterone production and pregnancy rates

Effect of human chorionic gonadotrophin on dominant follicles in cows: formation of accessory corpora lutea, progesterone production and pregnancy rates

Sincronização da onda folicular com hCG prévia à indução da luteólise com cloprostenol em bovinos

Systemic Progesterone Concentration Following Human Chorionic Gonadotropin Administration at Various Times during the Estrous Cycle in Beef Heifers

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