Regulation of Ovarian Function in Holstein Heifers with Sc-21009 Implants and Estradiol Valerate

Co, Woody; Fb, Abenes

doi:10.2527/jas1975.4141057x

Cited by 14 publications

(4 citation statements)

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“…Similarly, Woody and Abenes (1975) reported a range of 1 to 5 days in the interval to estrus in heifers treated with norgestomet and estradiol valerate. Since timing of insemination in relation to ovulation is an important consideration in efforts to achieve fertilization (McLaren, 1974), it is possible such variation among individuals in hormonal and behavioral events could contribute to a decrease in fertility at the controlled estrus.…”

Section: Syncro-mate-b-treated Heifersmentioning

confidence: 92%

“…Also, no effect of sire on pregnancy rate was detected (P>.05). In previous studies in which similar treatments were utilized (Wiltbank et al, 1971;Wishart and Young, 1974;Woody and Abenes, 1975;Wishart et al, 1977;Mares, 1978), synchronized animals inseminated either after estrus or at a predetermined time usually tended to have lower pregnancy rates than controls. However, in none of the studies were the decreased conception rates low enough to be considered significant at the 95% confidence level.…”

Section: Syncro-mate-b-treated Heifersmentioning

confidence: 99%

“…Further, comparison of endocrine data gathered from such an investigation, in conjunction with pregnancy rates of treated animals, would yield firsthand information relating reproductive hormone profiles to fertility. Synchro-Mate-B (SMB) has been shown to be a successful estrus control device, although some variability in fertility exists (Woody and Abenes, 1975;Mares, 1978;Smith et al, 1979). The objectives of this study were to investigate the effect of SMB treatment on endogenous follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17/3 (E) and progesterone (P) profiles during the treatment and subsequent breeding periods and to examine possible relationships between hormone profiles and subsequent pregnancy rates.…”

Section: Introductionmentioning

confidence: 99%

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Endogenous Hormone Response and Fertility in Dairy Heifers Treated with Norgestomet and Estradiol Valerate2

Kazmer

Barnes

Halman

1981

Journal of Animal Science

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Seventy postpuberal dairy heifers were assigned to remain untreated (n = 26) or to receive the Syncro-Mate-B (SMB) treatment (n = 44). Untreated heifers were inseminated at 12 hr after detection of estrus, while SMB-treated heifers were inseminated either at 48 hr after implant removal (group 1) or at 12 hr after detection of estrus (group 2). Jugular blood was collected at regular intervals from four untreated heifers and from 20 SMB heifers. In untreated heifers, estradiol-17 beta (E) was unchanged throughout the estrous cycle. Progesterone (P) reached maximum concentrations during the luteal phase and then declined to less than 2 ng/ml before estrus. Follicle stimulating hormone (FSH) ranged between 50.1 and 100.2 ng/ml during the estrous cycle, then reached a peak (P less than .05) concentration of 516.2 ng/ml coincident with peak luteinizing hormone (LH) concentration at 12 hr after the detection of estrus. In SMB-treated heifers, plasma E increased by 12 hr after injection of estradiol valerate and then declined throughout the rest of the sampling period. P declined to less than 2 ng/ml by 24 hr after administration of the SMB treatment and remained low throughout the sampling period. FSH declined in response to SMB treatment, then reached a peak (P less than .05) concentration coincident with peak LH 40 hr after implant removal. First service pregnancy rates among the untreated, group 1 and group 2 heifers, were 65, 58 and 38%, respectively, and did not differ (P greater than .05). SMB treatment was effective in inducing luteolysis and in suppressing estrus and peak gonadotropin release. Intervals from implant removal until estrus and from implant removal until peak gonadotropin release were highly variable among SMB-treated animals.

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Section: Syncro-mate-b-treated Heifersmentioning

confidence: 92%

Section: Syncro-mate-b-treated Heifersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Endogenous Hormone Response and Fertility in Dairy Heifers Treated with Norgestomet and Estradiol Valerate2

Kazmer

Barnes

Halman

1981

Journal of Animal Science

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“…Progesterone and progestins have been used for estrous control in cattle (Wiltbank and Kassen, 1968;Wiltbank et al, 1971;Woody and Abenes, 1975;Roche and Gosling, 1977), sheep (Hulet and Foote, 1967;Christenson, 1976) and swine (Polge, 1972;Webel, 1977). Daily intramuscular injection of progesterone for estrus and ovulation control of mares has produced variable results (Loy and Swan, 1966;Van Niekerk et al, 1973;lloltan et al, 1977).…”

Section: Introductionmentioning

confidence: 99%