Ovarian characteristics, serum hormoneconcentrations, and fertility in lactating dairy cows inresponse to equine chorionic gonadotropin (2010)

Pulley, Stephanie Leeann; Wallace, L. D.; Mellieon, H.I.; Stevenson, Jeffrey S.

doi:10.4148/2378-5977.2989

Cited by 2 publications

(8 citation statements)

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“…Study 4. Lactating Holstein cows (n = 124) in 1 herd (Pulley et al, 2013) were enrolled in a 7-d Ovsynch and alternately received eCG concurrent with PGF 2α . Cows were treated with GnRH-2 at 56 h after PGF 2α and inseminated 17 h later.…”

Section: Source Of Datamentioning

confidence: 99%

Physiological predictors of ovulation and pregnancy risk in a fixed-time artificial insemination program

Stevenson

2016

Journal of Dairy Science

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The objective of this study was to determine the relative importance and contribution of several physiological factors as predictors of pregnancy risk in an Ovsynch (GnRH-1 - 7d - PGF - 56h - GnRH-2 - 16h - artificial insemination) timed artificial insemination program: (1) age of the corpus luteum (CL; original CL, new CL, or both in response to GnRH-1) and resulting progesterone concentrations as they affected luteolysis, ovulation after GnRH-2, and pregnancy risk; (2) progesterone concentration before GnRH-1 and GnRH-2 on subsequent ovulatory response to GnRH-1 and GnRH-2 as well as pregnancy risk; and (3) a combination of these factors in a multivariable logistic regression model to predict pregnancy risk. Original data from 7 published studies were combined including ovulatory responses to both GnRH injections, blood progesterone concentrations before GnRH-1, before PGF, and at 48h after PGF, pregnancy per artificial insemination at d 32 and 60 after artificial insemination, and intervening pregnancy loss. Ovulation outcomes were greater at lesser progesterone concentrations after both GnRH injections despite the fact that pregnancy outcomes were greatest when progesterone exceeded 3ng/mL before GnRH-1 and PGF, suggesting that greater progesterone concentration before GnRH-1 and incidence of ovulation act via different mechanisms to improve subsequent fertility. Ovulation after GnRH-2 and subsequent pregnancy outcome were positively related to lesser concentrations of progesterone at 48h after PGF; however, for maximal pregnancy outcome, progesterone should be <0.5ng/mL. Cows with a CL that also formed a new CL after GnRH-1 had the greatest pregnancy outcome, whereas cows with only a new CL (i.e., anovulatory cows and those at or near estrus without a CL at GnRH-1) had the poorest pregnancy outcome. Pregnancy loss was not affected by CL status during the timed artificial insemination program. Receiver operator curves produced cut points of progesterone concentration that predicted ovulation and pregnancy risk. Selected cut points of progesterone concentration 48h after PGF produced true positive risks greater than 90% and false positive risks less than 25%, thus demonstrating the high predictability of ovulation after GnRH-2 and subsequent pregnancy outcome based on progesterone concentration. We conclude that progesterone concentration is highly predictive of ovulation and pregnancy risk in addition to body condition, size of ovulatory follicle, and parity.

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Section: Source Of Datamentioning

confidence: 99%

Physiological predictors of ovulation and pregnancy risk in a fixed-time artificial insemination program

Stevenson

2016

Journal of Dairy Science

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“…Likewise in dairy cattle, treatment of cows with an unknown CL status with 0, 1, or 2 progesterone inserts as part of an Ovsynch timed AI program did not alter subsequent P/AI, but cows with progesterone inserts had reduced premature luteolysis and fewer asynchronous post-AI estrous cycles than controls (Lima et al, 2009). Furthermore, when dairy cows were targeted in either a 5- (Bisinotto et al, 2013) or 7-d (Stevenson et al, 2008;Bisinotto et al, 2015a) Ovsynch timed AI program, P/AI was greater in non-CL cows treated with either 1 or 2 progesterone inserts compared with non-CL control cows, and P/AI of progesterone-treated non-CL cows was comparable with cows in diestrus Stevenson et al, 2008Stevenson et al, , 2012Stevenson and Phatak, 2010;Stevenson, 2011Stevenson, , 2016Pulley et al, 2013 cows on the basis of progesterone concentration categories at the onset of the ovulation synchronization program (7-d CO-Synch + CIDR timed AI program: beef = GnRH injection and CIDR insertion, 7 d later PGF 2α and insert removal, 48 to 72 h later GnRH and AI; dairy = GnRH injection, 7 d later PGF 2α , 48 to 56 h later GnRH and AI). An interaction of parity and progesterone category was detected (P = 0.011) such that P/AI in primiparous, but not in multiparous, beef cows was greater when progesterone concentrations >2 ng/mL.…”

Section: Prebreeding Progesterone Milieumentioning

confidence: 90%

“…(Figure 4A and 4B). (Stevenson et al, 2015) and for dairy cattle from 8 studies (Stevenson et al, 2008(Stevenson et al, , 2012Stevenson and Phatak, 2010;Stevenson, 2011Stevenson, , 2016Pulley et al, 2013. Prebreeding progesterone concentration at the time of PGF 2α injection had no effect on P/AI in beef cattle, whereas P/AI increased (P < 0.001) with increasing concentration of progesterone from <1.0 to 4.0 ng/mL in dairy cows.…”

Section: Progesterone Before Pgf and At Aimentioning

confidence: 93%

“…In contrast, increased serum concentrations of progesterone during the estrous cycle before conception have been associated with increased conception risk in beef and dairy cattle (see . Progesterone concentrations were examined in 3,046 beef cows represented 73 herd-years (Stevenson et al, 2015) and in 2,026 dairy cows from 8 published studies consisting of 4 different herds of Holstein cows (Stevenson et al, 2008(Stevenson et al, , 2012Stevenson and Phatak, 2010;Stevenson, 2011Stevenson, , 2016Pulley et al, 2013. The pattern of proportions of cows within progesterone concentration ranges at the time of PGF 2α seemed to differ between genotypes (Figure 3A).…”

Section: Progesterone Before Pgf and At Aimentioning

confidence: 99%

“…Panel B illustrates subsequent P/AI based on the progesterone concentration at timed AI (66 to 72 h after PGF 2α ) for beef cows or 24 h before timed AI (48 h after PGF 2α ) for dairy cows. Data for beef cows were adapted from 73 herd-years (Stevenson et al, 2015) and for dairy cattle from 8 studies (Stevenson et al, 2008(Stevenson et al, , 2012Stevenson and Phatak, 2010;Stevenson, 2011Stevenson, , 2016Pulley et al, 2013. Concentration of progesterone did not seem to affect subsequent P/AI in beef cattle, whereas P/AI was reduced (P < 0.01) at concentrations >0.80 ng/mL at AI in dairy cattle compared to concentration categories <0.80 ng/mL.…”

Section: Figurementioning

confidence: 99%

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Contrasting effects of progesterone on fertility of dairy and beef cows

Stevenson

Lamb

2016

Journal of Dairy Science

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The role of progesterone in maintaining pregnancy is well known in the bovine. Subtle differences exist between dairy and beef cows because of differing concentrations of progesterone during recrudescence of postpartum estrous cycles, rate of follicular growth and maturation, proportions of 2- and 3-follicular wave cycles, and other effects on pregnancy outcomes per artificial insemination (P/AI). Because proportions of anovulatory cows before the onset of the artificial insemination (AI) period are greater and more variable in beef (usually ranging from 30 to 70%) than dairy (25%) cows, AI programs were developed to accommodate anovulatory and cycling beef cows enrolled therein. Incorporating a progestin as part of an AI program in beef cows improved P/AI by reducing the proportion of cows having premature luteal regression and short post-AI luteal phases. In both genotypes, prolonged dominant follicle growth in a reduced progesterone milieu resulted in increased (1) LH pulses, (2) preovulatory follicle diameter, and (3) concentrations of estradiol and a subsequently larger corpora lutea (CL). In contrast, the progesterone milieu during growth of the ovulatory follicle in an ovulation control program does not seem to affect subsequent P/AI in beef cows, whereas in dairy cows follicle development in an elevated compared with a low progesterone environment increases P/AI. Progesterone status in beef cows at the onset of ovulation synchronization is not related to P/AI in multiparous cows, whereas P/AI was suppressed in primiparous cows that began a timed AI program in a low-progesterone environment. In timed AI programs, elevated concentrations of progesterone just before PGF2α and reduced concentrations at AI are critical to maximizing subsequent P/AI in dairy cows, but seemingly much less important in beef cows. By inducing ancillary CL and increasing concentrations of progesterone, human chorionic gonadotropin may increase P/AI when administered to beef cows 7d after AI or at embryo transfer, and its success seems to depend on induction of ancillary CL, whereas in dairy cows increased fertility was detected in cows with multiple CL, human chorionic gonadotropin-enhanced progesterone from original CL, or both. Pregnancy losses after AI are less frequent in beef cows and are not associated with pre-AI progesterone or cycling status, whereas losses in dairy cows are inversely related to progesterone and adversely affected in anovular dairy cows. Genotype and nutritional management likely influence several physiological differences including circulating concentrations of progesterone and responses to supplemental progesterone.

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Ovarian characteristics, serum hormoneconcentrations, and fertility in lactating dairy cows inresponse to equine chorionic gonadotropin (2010)

Cited by 2 publications

References 71 publications

Physiological predictors of ovulation and pregnancy risk in a fixed-time artificial insemination program

Physiological predictors of ovulation and pregnancy risk in a fixed-time artificial insemination program

Contrasting effects of progesterone on fertility of dairy and beef cows

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