{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T18:19:46Z","timestamp":1792520386822,"version":"4.5.0"},"reference-count":58,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2020,9,2]],"date-time":"2020-09-02T00:00:00Z","timestamp":1599004800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>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 2\u03b1. The time interval between G1 and prostaglandin F 2\u03b1 (PGF 2\u03b1) had to range from 5 to 7 d. The time interval between the PGF 2\u03b1 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 &lt; 0.001) the relative risk of conceiving (RR (relative risk) = 1.32; 95% CI = 1.21\u20131.45) in lactating dairy cows. Ovulation after G1 increased (p &lt; 0.001) the relative risk of conceiving (RR = 1.29; 95% CI = 1.20\u20131.38) 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).<\/jats:p>","DOI":"10.3390\/ani10091551","type":"journal-article","created":{"date-parts":[[2020,9,2]],"date-time":"2020-09-02T09:29:28Z","timestamp":1599038968000},"page":"1551","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Luteal Presence and Ovarian Response at the Beginning of a Timed Artificial Insemination Protocol for Lactating Dairy Cows Affect Fertility: A Meta-Analysis"],"prefix":"10.3390","volume":"10","author":[{"given":"Stefan","family":"Borchardt","sequence":"first","affiliation":[{"name":"Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universit\u00e4t Berlin, Koenigsweg 65, 14163 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alina","family":"Pohl","sequence":"additional","affiliation":[{"name":"Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universit\u00e4t Berlin, Koenigsweg 65, 14163 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wolfgang","family":"Heuwieser","sequence":"additional","affiliation":[{"name":"Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universit\u00e4t Berlin, Koenigsweg 65, 14163 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4723","DOI":"10.3168\/jds.S0022-0302(06)72522-X","article-title":"Survey of Management Practices on Reproductive Performance of Dairy Cattle on Large US Commercial Farms","volume":"89","author":"Caraviello","year":"2006","journal-title":"J. Dairy Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/j.cvfa.2016.01.007","article-title":"Synchronization and Artificial Insemination Strategies in Dairy Herds","volume":"32","author":"Stevenson","year":"2016","journal-title":"Vet. Clin. N. Am. Food Anim. Pract."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/0093-691X(95)00279-H","article-title":"Synchronization of ovulation in dairy cows using PGF2\u03b1 and GnRH","volume":"44","author":"Pursley","year":"1995","journal-title":"Theriogenology"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.theriogenology.2018.03.037","article-title":"Development of fertility programs to achieve high 21-day pregnancy rates in high-producing dairy cows","volume":"114","author":"Carvalho","year":"2018","journal-title":"Theriogenology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"5798","DOI":"10.3168\/jds.2010-3516","article-title":"Effect of interval between induction of ovulation and artificial insemination (AI) and supplemental progesterone for resynchronization on fertility of dairy cows subjected to a 5-d timed AI program","volume":"93","author":"Bisinotto","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1067","DOI":"10.1016\/S0093-691X(99)00195-8","article-title":"Synchronization rate, size of the ovulatory follicle, and pregnancy rate after synchronization of ovulation beginning on different days of the estrous cycle in lactating dairy cows","volume":"52","author":"Vasconcelos","year":"1999","journal-title":"Theriogenology"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.theriogenology.2013.09.017","article-title":"The cow as an induced ovulator: Timed AI after synchronization of ovulation","volume":"81","author":"Wiltbank","year":"2014","journal-title":"Theriogenology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2515","DOI":"10.3168\/jds.2014-9058","article-title":"Progesterone supplementation to lactating dairy cows without a corpus luteum at initiation of the Ovsynch protocol","volume":"98","author":"Bisinotto","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"639","DOI":"10.3168\/jds.2011-4418","article-title":"Increased fertility in lactating dairy cows resynchronized with Double-Ovsynch compared with Ovsynch initiated 32 d after timed artificial insemination","volume":"95","author":"Giordano","year":"2012","journal-title":"J. Dairy Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"8800","DOI":"10.3168\/jds.2015-9968","article-title":"Manipulation of progesterone to increase ovulatory response to the first GnRH treatment of an Ovsynch protocol in lactating dairy cows receiving first timed artificial insemination","volume":"98","author":"Carvalho","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"773","DOI":"10.1016\/j.theriogenology.2013.07.003","article-title":"Effect of increasing GnRH and PGF2\u03b1 dose during Double-Ovsynch on ovulatory response, luteal regression, and fertility of lactating dairy cows","volume":"80","author":"Giordano","year":"2013","journal-title":"Theriogenology"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4212","DOI":"10.3168\/jds.2007-0182","article-title":"Reducing the interval from presynchronization to initiation of timed artificial insemination improves fertility in dairy cows","volume":"90","author":"Santos","year":"2007","journal-title":"J. Dairy Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3781","DOI":"10.3168\/jds.2011-5155","article-title":"Effect of progesterone on magnitude of the luteinizing hormone surge induced by two different doses of gonadotropin-releasing hormone in lactating dairy cows","volume":"95","author":"Giordano","year":"2012","journal-title":"J. Dairy Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"6188","DOI":"10.3168\/jds.2015-9473","article-title":"Concentrations of luteinizing hormone and ovulatory responses in dairy cows before timed artificial insemination","volume":"98","author":"Pulley","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3003","DOI":"10.3168\/jds.2015-10091","article-title":"Feedback effects of estradiol and progesterone on ovulation and fertility of dairy cows after gonadotropin-releasing hormone-induced release of luteinizing hormone","volume":"99","author":"Stevenson","year":"2016","journal-title":"J. Dairy Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3168\/jds.2008-1404","article-title":"Invited review: Assessing experimental designs for research conducted on commercial dairies","volume":"92","author":"Tempelman","year":"2009","journal-title":"J. Dairy Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1009","DOI":"10.3168\/jds.2012-5892","article-title":"Evaluation of presynchronized resynchronization protocols for lactating dairy cows","volume":"96","author":"Chebel","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"8741","DOI":"10.3168\/jds.2015-9719","article-title":"Modifications to Ovsynch improve fertility during resynchronization: Evaluation of presynchronization with gonadotropin-releasing hormone 6 d before initiation of Ovsynch and addition of a second prostaglandin F2\u03b1 treatment","volume":"98","author":"Carvalho","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"6243","DOI":"10.3168\/jds.2015-9660","article-title":"Five-day resynchronization programs in dairy cows including presynchronization and progesterone at two stages following artificial insemination","volume":"98","author":"Pulley","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_20","unstructured":"(2020, February 01). Pubmed\u2014National Center for Biotechnology Information, Available online: https:\/\/www.ncbi.nlm.nih.gov\/."},{"key":"ref_21","unstructured":"(2020, February 01). Science Direct. Available online: http:\/\/www.sciencedirect.com."},{"key":"ref_22","unstructured":"(2020, February 01). Google Scholar. Available online: http:\/\/scholar.google.com."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Moher, D., Liberati, A., Tetzlaff, J., and Altman, D.G. (2009). Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med., 6.","DOI":"10.1371\/journal.pmed.1000097"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3508","DOI":"10.2527\/2004.82123508x","article-title":"Effect of addition of a progesterone intravaginal insert to a timed insemination protocol using estradiol cypionate on ovulation rate, pregnancy rate, and late embryonic loss in lactating dairy cows","volume":"82","author":"Santos","year":"2004","journal-title":"J. Anim. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"5436","DOI":"10.3168\/jds.2009-2134","article-title":"Effect of increasing amounts of supplemental progesterone in a timed artificial insemination protocol on fertility of lactating dairy cows","volume":"92","author":"Lima","year":"2009","journal-title":"J. Dairy Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"869","DOI":"10.1016\/j.theriogenology.2009.06.008","article-title":"Synchronization and resynchronization of inseminations in lactating dairy cows with the CIDR insert and the Ovsynch protocol","volume":"72","author":"Bartolome","year":"2009","journal-title":"Theriogenology"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.3168\/jds.S0022-0302(07)71606-5","article-title":"Evaluation of progesterone supplementation in a prostaglandin F2\u03b1-based presynchronization protocol before timed insemination","volume":"90","author":"Bicalho","year":"2007","journal-title":"J. Dairy Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7032","DOI":"10.3168\/jds.2013-6960","article-title":"Supplemental progesterone and timing of resynchronization on pregnancy outcomes in lactating dairy cows","volume":"96","author":"Bilby","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2214","DOI":"10.3168\/jds.2012-6038","article-title":"Targeted progesterone supplementation improves fertility in lactating dairy cows without a corpus luteum at the initiation of the timed artificial insemination protocol","volume":"96","author":"Bisinotto","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"922","DOI":"10.3168\/jds.2009-2301","article-title":"Supplementation of progesterone via controlled internal drug release inserts during ovulation synchronization protocols in lactating dairy cows","volume":"93","author":"Chebel","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"833","DOI":"10.1016\/j.theriogenology.2012.12.011","article-title":"Progesterone supplementation before timed AI increased ovulation synchrony and pregnancy per AI, and supplementation after timed AI reduced pregnancy losses in lactating dairy cows","volume":"79","author":"Colazo","year":"2013","journal-title":"Theriogenology"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"7640","DOI":"10.3168\/jds.2013-6750","article-title":"Pregnancy per artificial insemination in lactating dairy cows subjected to 2 different intervals from presynchronization to initiation of Ovsynch protocol","volume":"96","author":"Colazo","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4086","DOI":"10.3168\/jds.2010-3233","article-title":"Resynchronization strategies to improve fertility in lactating dairy cows utilizing a presynchronization injection of GnRH or supplemental progesterone: I. Pregnancy rates and ovarian responses","volume":"93","author":"Dewey","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1024","DOI":"10.3168\/jds.S0022-0302(04)73248-8","article-title":"Pregnancy in dairy cows after synchronized ovulation regimens with or without presynchronization and progesterone","volume":"87","author":"Cartmill","year":"2004","journal-title":"J. Dairy Sci."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3941","DOI":"10.3168\/jds.S0022-0302(03)74003-X","article-title":"Fertility of dairy cows after resynchronization of ovulation at three intervals following first timed insemination","volume":"86","author":"Fricke","year":"2003","journal-title":"J. Dairy Sci."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"746","DOI":"10.3168\/jds.2015-10083","article-title":"Effect of extending the interval from Presynch to initiation of Ovsynch in a Presynch-Ovsynch protocol on fertility of timed artificial insemination services in lactating dairy cows","volume":"99","author":"Giordano","year":"2016","journal-title":"J. Dairy Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1830","DOI":"10.1016\/j.theriogenology.2012.07.021","article-title":"Effect of presynchronization strategy before Ovsynch on fertility at first service in lactating dairy cows","volume":"78","author":"Gumen","year":"2012","journal-title":"Theriogenology"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"4488","DOI":"10.3168\/jds.2010-4126","article-title":"Evaluation of protocols to synchronize estrus and ovulation in seasonal calving pasture-based dairy production systems","volume":"94","author":"Herlihy","year":"2011","journal-title":"J. Dairy Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"7003","DOI":"10.3168\/jds.2011-5260","article-title":"Presynchronization with Double-Ovsynch improves fertility at first postpartum artificial insemination in lactating dairy cows","volume":"95","author":"Herlihy","year":"2012","journal-title":"J. Dairy Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3788","DOI":"10.3168\/jds.2012-6429","article-title":"Effect of timing of initiation of resynchronization and presynchronization with gonadotropin-releasing hormone on fertility of resynchronized inseminations in lactating dairy cows","volume":"96","author":"Lopes","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1944","DOI":"10.3168\/jds.2009-2305","article-title":"Effects of treatment of anestrous dairy cows with gonadotropin-releasing hormone, prostaglandin, and progesterone","volume":"93","author":"McDougall","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2976","DOI":"10.3168\/jds.2009-2870","article-title":"Effect of reducing the period of follicle dominance in a timed artificial insemination protocol on reproduction of dairy cows","volume":"93","author":"Santos","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"5509","DOI":"10.3168\/jds.2007-0315","article-title":"Effect of pretreatment with prostaglandin F2\u03b1 before resynchronization of ovulation on fertility of lactating dairy cows","volume":"90","author":"Silva","year":"2007","journal-title":"J. Dairy Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"4237","DOI":"10.3168\/jds.S0022-0302(06)72469-9","article-title":"Treatment with gonadotropin-releasing hormone after first timed artificial insemination improves fertility in noncycling lactating dairy cows","volume":"89","author":"Sterry","year":"2006","journal-title":"J. Dairy Sci."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2567","DOI":"10.3168\/jds.S0022-0302(06)72333-5","article-title":"Treatment of cycling and noncycling lactating dairy cows with progesterone during Ovsynch","volume":"89","author":"Stevenson","year":"2006","journal-title":"J. Dairy Sci."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2901","DOI":"10.3168\/jds.2007-0856","article-title":"Detection of anovulation by heatmount detectors and transrectal ultrasonography before treatment with progesterone in a timed insemination protocol","volume":"91","author":"Stevenson","year":"2008","journal-title":"J. Dairy Sci."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"8566","DOI":"10.3168\/jds.2017-14191","article-title":"Short communication: Effect of adding a second prostaglandin F2\u03b1 injection during the Ovsynch protocol on luteal regression and fertility in lactating dairy cows: A meta-analysis","volume":"101","author":"Borchardt","year":"2018","journal-title":"J. Dairy Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1002\/jrsm.12","article-title":"A basic introduction to fixed-effect and random-effects models for meta-analysis","volume":"1","author":"Borenstein","year":"2010","journal-title":"Res. Synth. Methods"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/0197-2456(86)90046-2","article-title":"Meta-analysis in clinical trials","volume":"7","author":"DerSimonian","year":"1986","journal-title":"Control. Clin. Trials"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1136\/bmj.327.7414.557","article-title":"Measuring inconsistency in meta-analyses","volume":"327","author":"Higgins","year":"2003","journal-title":"BMJ"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"10077","DOI":"10.3168\/jds.2016-11247","article-title":"Physiological predictors of ovulation and pregnancy risk in a fixed-time artificial insemination program","volume":"99","author":"Stevenson","year":"2016","journal-title":"J. Dairy Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"2139","DOI":"10.3168\/jds.S0022-0302(98)75790-X","article-title":"Effect of time of artificial insemination on pregnancy rates, calving rates, pregnancy loss, and gender ratio after synchronization of ovulation in lactating dairy cows","volume":"81","author":"Pursley","year":"1998","journal-title":"J. Dairy Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1095\/biolreprod32.3.574","article-title":"Pituitary luteinizing hormone-releasing hormone receptors in ovariectomized cows after challenge with ovarian steroids","volume":"32","author":"Schoenemann","year":"1985","journal-title":"Biol. Reprod."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/S0739-7240(02)00143-1","article-title":"Pituitary effects of steroid hormones on secretion of follicle-stimulating hormone and luteinizing hormone","volume":"23","author":"Nett","year":"2002","journal-title":"Domest. Anim. Endocrinol."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"3342","DOI":"10.3168\/jds.2010-3734","article-title":"Concentration of progesterone during the development of the ovulatory follicle: I. Ovarian and embryonic responses","volume":"94","author":"Cerri","year":"2011","journal-title":"J. Dairy Sci."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1016\/j.theriogenology.2016.04.038","article-title":"Mechanisms underlying reduced fertility in anovular dairy cows","volume":"86","author":"Santos","year":"2016","journal-title":"Theriogenology"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"2472","DOI":"10.3168\/jds.2014-8954","article-title":"Meta-analysis of progesterone supplementation during timed artificial insemination programs in dairy cows","volume":"98","author":"Bisinotto","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"1568","DOI":"10.1016\/j.theriogenology.2011.08.012","article-title":"Managing the dominant follicle in lactating dairy cows","volume":"76","author":"Wiltbank","year":"2011","journal-title":"Theriogenology"}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/10\/9\/1551\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:05:44Z","timestamp":1760177144000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/10\/9\/1551"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,9,2]]},"references-count":58,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2020,9]]}},"alternative-id":["ani10091551"],"URL":"https:\/\/doi.org\/10.3390\/ani10091551","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,9,2]]}}}