Luteal Presence and Ovarian Response at the Beginning of a Timed Artificial Insemination Protocol for Lactating Dairy Cows Affect Fertility: A Meta-Analysis

Progesterone (P4) concentration during follicular growth has a major impact on fertility response in timed artificial insemination (TAI) protocols. Luteal presence at the beginning of a TAI protocol and ovarian response after the first gonadotropin-releasing hormone (GnRH) injection (G1) affect P4 concentration and subsequently pregnancy per artificial insemination (P/AI). A systematic review of the literature and meta-analytical assessment was performed with the objective of evaluating the magnitude of the effect of luteal presence and ovarian response at the beginning of a TAI protocol on P/AI in lactating dairy cows. We considered only studies using synchronisation protocols consisting of GnRH and prostaglandin F 2α. The time interval between G1 and prostaglandin F 2α (PGF 2α) had to range from 5 to 7 d. The time interval between the PGF 2α injection and G2 had to range from 48 to 72 h. We used 28 controlled experiments from 27 published manuscripts including 16,489 cows with the objective of evaluating the effect size of having a functional corpus luteum (CL) at G1 on P/AI. Information regarding ovulatory response after G1 was available for 5676 cows. In a subset of cows (n = 4291), information was available for luteal presence and ovulatory response at the initiation of the TAI protocol. A functional CL at G1 increased (p < 0.001) the relative risk of conceiving (RR (relative risk) = 1.32; 95% CI = 1.21–1.45) in lactating dairy cows. Ovulation after G1 increased (p < 0.001) the relative risk of conceiving (RR = 1.29; 95% CI = 1.20–1.38) in lactating dairy cows. The effect of ovulatory response on P/AI after G1 was affected by luteal presence at G1. In summary, there was a clear benefit on P/AI for cows starting a TAI protocol with a functional CL (+10.5 percentage units) and cows ovulating at the beginning of a TAI protocol (+11.0 percentage units).

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Additional small dose of prostaglandin F 2α at timed artificial insemination failed to improve pregnancy risk of lactating dairy cows

Theriogenology ◽

10.1016/j.theriogenology.2017.12.051 ◽

2018 ◽

Vol 110 ◽

pp. 27-33 ◽

Cited By ~ 2

Author(s):

J.A. Sauls ◽

B.E. Voelz ◽

L.G.D. Mendonça ◽

J.S. Stevenson

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Small Dose ◽

Pregnancy Risk ◽

Lactating Dairy Cows ◽

Prostaglandin F ◽

Timed Artificial Insemination

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A simple and practical short-term timed artificial insemination protocol using estradiol benzoate with prostaglandin F2α in lactating dairy cows

Theriogenology ◽

10.1016/j.theriogenology.2019.09.024 ◽

2020 ◽

Vol 141 ◽

pp. 197-201 ◽

Cited By ~ 2

Author(s):

Kazuhiro Bandai ◽

Hiromi Kusaka ◽

Hiroshi Miura ◽

Motohiro Kikuchi ◽

Minoru Sakaguchi

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Prostaglandin F2α ◽

Estradiol Benzoate ◽

Short Term ◽

Lactating Dairy Cows ◽

Timed Artificial Insemination

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Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows

Czech Journal of Animal Science ◽

10.17221/1283-cjas ◽

2011 ◽

Vol 56 (No. 6) ◽

pp. 279-283 ◽

Cited By ~ 1

Author(s):

A. Gümen ◽

A. Keskin ◽

G. Yilmazbas-Mecitoglu ◽

E. Karakaya ◽

S. Cevik ◽

...

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Reproductive Tract ◽

Female Reproductive Tract ◽

Conception Rate ◽

Beneficial Effects ◽

Lactating Dairy Cows ◽

Conception Rates ◽

Prostaglandin F ◽

And Control

In several studies, hormones such as gonadotropin-releasing hormone (GnRH), prostaglandins and oxytocin were used to increase pregnancy rate by inducing ovulation and improving the sperm transport in the female reproductive tract in lactating dairy cattle. The objective of this study was to compare the effects of GnRH, prostaglandin F2α (PGF2α) and oxytocin treatments at the time of artificial insemination (AI) after spontaneous oestrus on the conception rate (CR) of lactating dairy cows. Oestrus was detected by visual observations by experienced personnel. All cows (n = 430, 308 Holstein-Frisian and 122 Swedish-Red dairy cows) were inseminated based on the am/pm rule by veterinarians of the farm. After AI, cows were alternately assigned to one of the four treatment groups: (1) GnRH (n = 113); (2) PGF2α (n = 106); (3) oxytocin (n = 106) and (4) non-treated control (n = 105). Pregnancy diagnosis was performed 28–34 and 58–64 days post-insemination by transrectal ultrasonography. Conception rates on days 28–34 and 58–64 were not different among GnRH (46.0%; 52/113 and 44.3%; 50/113), PGF2α (37.7%; 40/106 and 35.9%; 38/106) and control (49.5%; 52/105 and 47.6%; 50/105) groups. However, conception rates were lower (P = 0.02) in oxytocin (31.1%; 33/106 and 30.2%; 32/106) than in GnRH and control groups on days 28–34 and 58–64. Other covariant factors, such as milk production, days in milk (DIM), breed, parity, service number did not affect the conception rate. Thus, there were no beneficial effects of treatments with GnRH and PGF2α at the time of AI, and oxytocin had an adverse effect on CR in lactating dairy cows in this study.

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