{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T21:23:32Z","timestamp":1782422612621,"version":"3.54.5"},"reference-count":35,"publisher":"Elsevier BV","license":[{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/legal\/tdmrep-license"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-017"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-012"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-004"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002715","name":"Alberta Livestock and Meat Agency Ltd","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002715","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["Animal Reproduction Science"],"published-print":{"date-parts":[[2022,5]]},"DOI":"10.1016\/j.anireprosci.2022.106975","type":"journal-article","created":{"date-parts":[[2022,4,11]],"date-time":"2022-04-11T11:48:22Z","timestamp":1649677702000},"page":"106975","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":5,"special_numbering":"C","title":["Development of a letrozole-based synchronization protocol for fixed-time artificial insemination in beef cattle"],"prefix":"10.1016","volume":"240","author":[{"given":"Eric M.","family":"Zwiefelhofer","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Will","family":"Lillico","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gregg P.","family":"Adams","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","reference":[{"key":"10.1016\/j.anireprosci.2022.106975_bib1","doi-asserted-by":"crossref","first-page":"1022","DOI":"10.2527\/jas.2013-6761","article-title":"Effect of follicle age on conception rate in beef heifers","volume":"92","author":"Abreu","year":"2014","journal-title":"J. Anim. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib2","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.2527\/jas.2013-6760","article-title":"The effect of follicle age on pregnancy rate in beef cows","volume":"92","author":"Abreu","year":"2014","journal-title":"J. Anim. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib3","doi-asserted-by":"crossref","first-page":"3413","DOI":"10.3168\/jds.S0022-0302(06)72378-5","article-title":"Optimizing ovulation to first GnRH improved outcomes to each hormonal injection of ovsynch in lactating dairy cows","volume":"89","author":"Bello","year":"2006","journal-title":"J. Dairy Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib4","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1016\/0093-691X(93)90261-3","article-title":"Effect of estradiol valerate on ovarian follicles, emergence of follicular waves and circulating gonadotropins in heifers","volume":"40","author":"Bo","year":"1993","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib5","doi-asserted-by":"crossref","first-page":"1555","DOI":"10.1016\/0093-691X(94)90821-Y","article-title":"Follicular wave dynamics after estradiol-17\u03b2 treatment of heifers with or without a progestogen implant","volume":"41","author":"Bo","year":"1994","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib6","doi-asserted-by":"crossref","first-page":"2039","DOI":"10.3168\/jds.S0022-0302(03)73793-X","article-title":"Intravaginal progesterone insert to synchronize return to estrus of previously inseminated dairy cows","volume":"86","author":"Chenault","year":"2003","journal-title":"J. Dairy Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib7","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1016\/j.theriogenology.2011.03.013","article-title":"Neither duration of progesterone insert nor initial GnRH treatment affected pregnancy per timed-insemination in dairy heifers subjected to a Co-synch protocol","volume":"76","author":"Colazo","year":"2011","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib8","first-page":"32","article-title":"Comparison of 2 enzyme immunoassays and a radioimmunoassay for measurement of progesterone concentrations in bovine plasma, skim milk, and whole milk","volume":"72","author":"Colazo","year":"2008","journal-title":"Can. J. Vet. Res."},{"key":"10.1016\/j.anireprosci.2022.106975_bib9","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1016\/j.theriogenology.2009.02.017","article-title":"Pregnancy rates to timed artificial insemination in dairy cows treated with gonadotropin-releasing hormone or porcine luteinizing hormone","volume":"72","author":"Colazo","year":"2009","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib10","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1016\/j.theriogenology.2013.01.003","article-title":"Effect of progesterone concentration and duration of proestrus on fertility in beef cattle after fixed-time artificial insemination","volume":"79","author":"Dadarwal","year":"2013","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib11","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1530\/jrf.0.0590463","article-title":"Fertilization and embryonic mortality rates in beef heifers after artificial insemination","volume":"59","author":"Diskin","year":"1980","journal-title":"J. Reprod. Fertil."},{"key":"10.1016\/j.anireprosci.2022.106975_bib12","first-page":"266","article-title":"Phase I study of the oral nonsteroidal aromatase inhibitor CGS 20267 in postmenopausal patients with advanced breast cancer","volume":"53","author":"Iveson","year":"1993","journal-title":"Cancer Res"},{"key":"10.1016\/j.anireprosci.2022.106975_bib13","doi-asserted-by":"crossref","first-page":"286","DOI":"10.3168\/jds.S0022-0302(97)75936-8","article-title":"Response of dairy cows treated with bovine somatotropin to a luteolytic dose of prostaglandin F2\u03b1.","volume":"80","author":"Kirby","year":"1997","journal-title":"J. Dairy Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.anireprosci.2008.08.009","article-title":"Oestrous synchronisation in cattle--current options following the EU regulations restricting use of oestrogenic compounds in food-producing animals: a review","volume":"109","author":"Lane","year":"2008","journal-title":"Anim. Reprod. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib15","doi-asserted-by":"crossref","first-page":"1003","DOI":"10.21451\/1984-3143-AR2018-0007","article-title":"Evolution of knowledge on ovarian physiology and its contribution to the widespread application of reproductive biotechnologies in South American cattle","volume":"15","author":"Mapletoft","year":"2018","journal-title":"Anim. Reprod."},{"key":"10.1016\/j.anireprosci.2022.106975_bib16","first-page":"8","article-title":"Intravaginal device-type and treatment-length for ovine estrus synchronization modify vaginal mucus and microbiota and affect fertility","author":"Martinez-Ros","year":"2018","journal-title":"Animals"},{"key":"10.1016\/j.anireprosci.2022.106975_bib17","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/S0015-0282(00)01705-2","article-title":"Use of an aromatase inhibitor for induction of ovulation in patients with an inadequate response to clomiphene citrate","volume":"75","author":"Mitwally","year":"2001","journal-title":"Fertil. Steril."},{"key":"10.1016\/j.anireprosci.2022.106975_bib18","doi-asserted-by":"crossref","first-page":"1646","DOI":"10.3168\/jds.S0022-0302(01)74600-0","article-title":"Effects of presynchronization and bovine somatotropin on pregnancy rates to a timed artificial insemination protocol in lactating dairy cows","volume":"84","author":"Moreira","year":"2001","journal-title":"J. Dairy Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib19","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1007\/s00441-012-1386-8","article-title":"Follicular determinants of pregnancy establishment and maintenance","volume":"349","author":"Pohler","year":"2012","journal-title":"Cell Tissue Res"},{"key":"10.1016\/j.anireprosci.2022.106975_bib20","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/0093-691X(95)00279-H","article-title":"Synchronization of ovulation in dairy cows using PGF2a and GnRH","volume":"44","author":"Pursley","year":"1995","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib21","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1530\/jrf.0.1060039","article-title":"Prolonged dominance of follicles and reduced viability of bovine oocytes","volume":"106","author":"Revah","year":"1996","journal-title":"Reproduction"},{"key":"10.1016\/j.anireprosci.2022.106975_bib22","doi-asserted-by":"crossref","first-page":"300","DOI":"10.2527\/jas1986.622300x","article-title":"Effect of varying levels of postpartum nutrition and body condition at calving on subsequent reproductive performance in beef cattle","volume":"62","author":"Richards","year":"1986","journal-title":"J. Anim. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib23","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.anireprosci.2016.01.013","article-title":"Expression of estrus before fixed-time AI affects conception rates and factors that impact expression of estrus and the repeatability of expression of estrus in sequential breeding seasons","volume":"166","author":"Richardson","year":"2016","journal-title":"Anim. Reprod. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib24","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1016\/j.theriogenology.2008.03.014","article-title":"A new presynchronization system (Double-Ovsynch) increases fertility at first postpartum timed AI in lactating dairy cows","volume":"70","author":"Souza","year":"2008","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib25","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.anireprosci.2013.02.010","article-title":"Comparison of two intravaginal progesterone releasing devices (PRID-Delta vs CIDR) in dairy cows: blood progesterone profile and field fertility","volume":"138","author":"van Werven","year":"2013","journal-title":"Anim. Reprod. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib26","doi-asserted-by":"crossref","first-page":"1513","DOI":"10.1016\/j.theriogenology.2003.09.001","article-title":"Effect of post-insemination supplementation with PRID on pregnancy in repeat-breeder Holstein cows","volume":"61","author":"Villarroel","year":"2004","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib27","first-page":"43","article-title":"Safety of a progesterone-releasing intravaginal device as assessed from vaginal mucosal integrity and indicators of systemic inflammation in postpartum dairy cows","volume":"72","author":"Walsh","year":"2008","journal-title":"Can. J. Vet. Res."},{"key":"10.1016\/j.anireprosci.2022.106975_bib28","doi-asserted-by":"crossref","DOI":"10.1016\/j.anireprosci.2021.106691","article-title":"Cholesterol-cyclodextrin complex as a replacement for egg yolk in bull semen extender: Sperm characteristics post-thawing and in vivo fertility","volume":"225","author":"Yang","year":"2021","journal-title":"Anim. Reprod. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib29","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.anireprosci.2015.03.005","article-title":"Formulation and testing of a non-steroidal aromatase inhibitor intravaginal device for the control of ovarian function in cattle","volume":"156","author":"Yapura","year":"2015","journal-title":"Anim. Reprod. Sci."},{"key":"10.1016\/j.anireprosci.2022.106975_bib30","unstructured":"Yapura, M., 2015. Development of a non-steroidal aromatase inhibitor-based protocol for the control of ovarian function using a bovine model- PhD Thesis. University of Saskatchewan."},{"key":"10.1016\/j.anireprosci.2022.106975_bib31","doi-asserted-by":"crossref","first-page":"1382","DOI":"10.1016\/j.theriogenology.2015.12.012","article-title":"Synchronization of ovulation in cattle with an aromatase inhibitor-based protocol","volume":"85","author":"Yapura","year":"2016","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib32","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1071\/RDv23n1Ab176","article-title":"Effects of vehicle and route of administration of letrozole on ovarian function in cattle","volume":"23","author":"Yapura","year":"2014","journal-title":"Reprod. Fertil. Dev."},{"key":"10.1016\/j.anireprosci.2022.106975_bib33","first-page":"112","article-title":"Aromatase inhibitors: a new approach for controlling ovarian function in cattle","author":"Yapura","year":"2018","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib34","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1016\/j.theriogenology.2020.02.008","article-title":"Research and development of a silicone letrozole-releasing device to control reproduction in cattle","volume":"146","author":"Zwiefelhofer","year":"2020","journal-title":"Theriogenology"},{"key":"10.1016\/j.anireprosci.2022.106975_bib35","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.theriogenology.2020.07.019","article-title":"An attempt to potentiate the ovarian superstimulatory response in cattle by co-treatment with an aromatase inhibitor","volume":"157","author":"Zwiefelhofer","year":"2020","journal-title":"Theriogenology"}],"container-title":["Animal Reproduction Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0378432022000549?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0378432022000549?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T06:47:08Z","timestamp":1759906028000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0378432022000549"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5]]},"references-count":35,"alternative-id":["S0378432022000549"],"URL":"https:\/\/doi.org\/10.1016\/j.anireprosci.2022.106975","relation":{},"ISSN":["0378-4320"],"issn-type":[{"value":"0378-4320","type":"print"}],"subject":[],"published":{"date-parts":[[2022,5]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"Development of a letrozole-based synchronization protocol for fixed-time artificial insemination in beef cattle","name":"articletitle","label":"Article Title"},{"value":"Animal Reproduction Science","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1016\/j.anireprosci.2022.106975","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"article","name":"content_type","label":"Content Type"},{"value":"\u00a9 2022 Elsevier B.V. All rights reserved.","name":"copyright","label":"Copyright"}],"article-number":"106975"}}