A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin on day five of the estrous cycle.

Schmitt, Éric; Barros, C. M.; Fields, Phillip A.; Fields, Michael J.; Diaz, T.; Kluge, Judith; Thatcher, W.W.

doi:10.2527/1996.7481915x

Cited by 94 publications

(106 citation statements)

References 34 publications

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“…Previous studies in goats had associated the use of hCG to induction acessory corpus luteum, induction of estrus (Fonseca et al, 2006), and also to overcome the negative effect of premature regression of corpora lutea after superovulatory treatment (Saharrea et al, 1998). In goats, the plasma hCG profile following 500 IU hCG administration was characterized by rapid absorption (11.6h) and slow elimination (70.0h) (Saleh et al, 2012), different from cows, that lasted a total of 30h (Schmitt et al, 1996). In the present study no differences were observed in any reproductive end point evaluated in dairy goats when receiving or not hCG.…”

Section: Discussionmentioning

confidence: 99%

Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

Esteves

Brandão

Cruz

et al. 2013

Arq. Bras. Med. Vet. Zootec.

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The objective of this study was to evaluate the efficiency of two doses of PGF associated or not to hCG on the associated reproductive parameters in dairy goats. A total of 29 goats received two doses of 30μg d-cloprostenol latero-vulvar at a 10 day intervals (Day 1 and Day 10). The does were allocated according to body weight and body condition score into two treatments, to receive hCG (250IU) or saline at estrus onset. After the second dose of PGF, estrus was monitored and ultrasound exams were performed twice daily. All does were inseminated 16h after estrus onset. Blood collection was performed every day for progesterone assay. The use of hCG at estrus onset did not affect any studied parameter and therefore the data were pooled.

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Section: Discussionmentioning

confidence: 99%

Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

Esteves

Brandão

Cruz

et al. 2013

Arq. Bras. Med. Vet. Zootec.

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“…However, circulating P4 remained lower, even after hCG treatment, in lactating cows compared with normally ovulating heifers. Eight studies that evaluated the effect of hCG on P4 concentrations from days 4 to 7 after AI in lactating dairy cows reported significant increases in circulating P4 concentrations after treatments with different doses of hCG: 3300 IU (Schmitt et al, 1996;Santos et al, 2001), 2500 IU (Stevenson et al, 2007b;Vasconcelos et al, 2011); 1500 IU (Walton et al, 1990;Hanlon et al, 2005; Kendall et al, 2009) or 1000 IU (Rajamahendran and Sianangama, 1992). Thus, treatment with hCG on day 5 after AI produces a consistent, fairly rapid (3 days delay) increase in circulating P4 in lactating dairy cows.…”

Section: Importance Of High P4 After Aimentioning

confidence: 99%

Physiological and practical effects of progesterone on reproduction in dairy cattle

Wiltbank

Souza

Carvalho

et al. 2014

Animal

185

114

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The discovery of progesterone (P4) and elucidation of the mechanisms of P4 action have an important place in the history of endocrinology and reproduction. Circulating P4 concentration is determined by a balance between P4 production, primarily by the corpus luteum (CL), and P4 metabolism, primarily by the liver. The volume of luteal tissue and number and function of large luteal cells are primary factors determining P4 production. Rate of P4 metabolism is generally determined by liver blood flow and can be of critical importance in determining circulating P4 concentrations, particularly in dairy cattle. During timed artificial insemination (AI) protocols, elevations in P4 are achieved by increasing number of CL by creating accessory CL or by supplementation with exogenous P4. Dietary manipulations can also alter circulating P4, although practical methods to apply these techniques have not yet been reported. Elevating P4 before the timed AI generally decreases double ovulation and increases fertility to the timed AI. Near the time of AI, slight elevations in circulating P4, possibly due to inadequate luteal regression, can dramatically reduce fertility. After AI, circulating P4 is critical for embryo growth and establishment and maintenance of pregnancy. Many studies have attempted to improve fertility by elevating P4 after timed AI. Our recent meta-analysis and manipulative study indicated small fertility benefits (3% to 3.5%) mostly in primiparous cows. Thus, previous research has provided substantial insight into mechanisms regulating circulating P4 concentrations and actions. Understanding this prior research can focus future research on P4 manipulation to improve reproductive success. Keywords: progesterone, lactating dairy cows, fertility ImplicationsThis manuscript reviews effects of circulating progesterone (P4) on dairy cattle reproduction. Various methods to elevate P4 during growth of the preovulatory follicular wave have been shown to increase pregnancies/ artificial insemination (AI) and reduce double ovulation, providing methods to improve fertility and reduce twinning rate in lactating dairy cattle. Conversely, very low concentrations of P4 near AI are needed to optimize fertility. Finally, elevations of P4 after AI can impact embryonic development and also may elevate fertility. Thus, innovative strategies to optimize circulating P4 concentrations during selected reproductive periods enhance our management tools for improving reproductive efficiency of lactating dairy cows. Discovery of Progesterone (P4)The discovery of P4 begins with a clear description by Regnier deGraaf (1641-1673) of the corpus luteum (CL), calling them 'globules' and correctly surmising (for rabbits) that 'the number of globules equals the number of offspring from a particular mating ' (deGraaf, 1672 in (Jocelyn andSetchell, 1972)). A key discovery came in the laboratory of Gustav Born , an excellent histologist, who observed that the CL was a ductless gland and correctly advanced the idea that it was a gland of internal sec...

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“…The use of GnRH (Lewis et al, 1990;Schmitt et al, 1996a) or hCG (Mancio et al, 1999;Santos et al, 2001) after AI increases P4 secretion due to the luteotropic effect (Kerbler et al, 1997;Santos et al, 2001) and/or induction of an accessory corpus luteum (aCL) (Schmitt et al, 1996a;Fonseca et al, 2001;Santos et al, 2001); thus, increasing progesterone concentration and, potentially, also conception.…”

Section: Introductionmentioning

confidence: 99%

Conception rate in Holstein cows treated with GnRH or hCG on the fifth day post artificial insemination during summer

Beltran

Vasconcelos

2008

Arq. Bras. Med. Vet. Zootec.

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Lactating Holstein cows (n=158), at 213±112 days in milking and averaging 26±9kg of milk per day, were randomly assigned to one of three treatment groups: control (CG, n=52, saline), GnRH (GG, n=55, 100µg gonadorelin), and hCG (HG, n=51, 2500IU) given five days after artificial insemination (AI). Rectal temperature was taken at the moment of AI and blood samples were collected five, seven, and 12 days after AI. Pregnancy was determined between 42 and 49 days after AI. Concentration of progesterone (P4) in serum (ng/ml, mean±SE) for CG, GG, and HG were, respectively, 2.7±0.4, 2.5±0.4, and 3.2±0.5 on day 5; 4.8±0.4, 4.2±0.4, and 5.7±0.5 on day 7; and 5.2±0.4, 6.9±0.4, and 8.5±0.5 on day 12 after AI. P4 concentration had proportional increase in serum between days 5 and 7 after AI (CG: 178%, GG: 168%, and HG: 178%), suggesting that the treatments did not induce a luteotropic effect on the existing corpus luteum (CL). Concentrations of P4 increased between days 7 and 12 in cows treated with GnRH and hCG (GG: 164%, and HG: 149%, P<0.01); but not in control cows (GC: 18%, P=0.31), suggesting that a new CL was formed. Treatments with GnRH or hCG increased conception rates in cows with rectal temperature below 39.7°C (CG: 10.1%, n=26, GG: 36.8%, n=27; and HG: 32.8%, n=21), but not in cows with rectal temperature above 39.7°C (CG: 15.2%, n=26; GG: 17.8%, n=28; and HG: 24.4%, n=30). These data suggest that high body temperature masked the positive impact of treatment with GnRH or hCG on day 5 after AI on conception.Keywords: dairy cow, conception, progesterone, hCG, GnRH (GC, n=52, salina); GnRH (GG, n=55, 100mcg de gonadorelina); e hCG (GH, n=51, 2500UI de hCG) RESUMO Vacas da raça Holandesas em lactação (n=158) aos 213±112 dias de lactação e produção de 26±9kg leite/dia, foram aleatoriamente distribuídas em três grupos: controle

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A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin on day five of the estrous cycle.

Cited by 94 publications

References 34 publications

Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

Physiological and practical effects of progesterone on reproduction in dairy cattle

Conception rate in Holstein cows treated with GnRH or hCG on the fifth day post artificial insemination during summer

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