{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T23:40:23Z","timestamp":1788824423397,"version":"build-2803163510"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,4,5]],"date-time":"2022-04-05T00:00:00Z","timestamp":1649116800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>The purpose of this study is to compare five protocols of estrous synchronization for Hu ewes to obtain the most effective and economical protocol, to apply the advantageous scheme in large-scale sheep farming. Healthy multiparous Hu ewes (<jats:italic>n<\/jats:italic> = 150) were randomly divided into five groups, and all ewes were administered fluorogestone acetate (FGA, 45 mg) vaginal sponge. The sponges of the first three groups (Groups I, II, and III) were removed on the 11th day, and 0.1 mg of PGF<jats:sub>2\u03b1<\/jats:sub> was injected intramuscularly on the ninth day. Group I received 6 \u03bcg of gonadotropin-releasing hormone (GnRH) by intramuscular injection at 36th h after withdrawal of the sponge. Group II was injected 330 IU of pregnant mare serum gonadotropin (PMSG) on the ninth day. The combination of 6 \u03bcg of GnRH and 330 IU of PMSG was treated in Group III at the same time as Group I and Group II. The sponges of the latter two groups (Groups IV and V) were removed on the 13th day, and 330 IU of PMSG was injected intramuscularly simultaneously. PGF<jats:sub>2\u03b1<\/jats:sub> (0.1 mg) was administered on the 12th day in Group IV. All ewes were detected for estrus at 24, 36, 48, 60, and 72 h after the sponge removal. The loss of sponge and vaginitis was recorded when the sponge was withdrawn. Cervical artificial insemination (AI) was performed with fresh semen of Dorper rams diluted with skimmed milk. After 30 days of insemination, the conception was detected with a veterinary B-ultrasound scanner. The lambing status of all ewes and the cost of drugs for estrous synchronization in each group were recorded. The results showed the following: (1) on the whole, the average percentage of estrous ewes in the period of 24\u201336 h and 36\u201348 h after removal was significantly higher than other three periods and that of the period of 60\u201372 h was significantly lower than the first three periods after removal; (2) there was no significant difference in percentages of estrous ewes in any of the five time periods, sponge loss rate, vaginitis rate, total percentage of estrous ewes, conception rate, single lambing rate, twinning rate, and multiple lambing rate of ewes among five protocols; (3) total percentage of estrous ewes and conception rate were more than or equal to 80% in the Groups II and III, and the twinning lamb rate of the Group II protocol was 70%; (4) there was no difference in lambing rate of ewes among Groups II, III, IV, and V; (5) the Group III had the highest drug cost of 22.5 CNY. In conclusion, considering the lambing rate, twinning lamb rate, and drug cost for estrous synchronization, Group II was the most advisable for application and promotion in large-scale sheep farms among these five protocols of estrus synchronization.<\/jats:p>","DOI":"10.3389\/fvets.2022.843514","type":"journal-article","created":{"date-parts":[[2022,4,6]],"date-time":"2022-04-06T07:37:58Z","timestamp":1649230678000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":22,"title":["Comparison of Five Protocols of Estrous Synchronization on Reproductive Performance of Hu Sheep"],"prefix":"10.3389","volume":"9","author":[{"given":"Xiaojie","family":"Yu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanyuan","family":"Bai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiangfeng","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaokun","family":"Zhao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jing","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,4,5]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"32","DOI":"10.1016\/j.anireprosci.2009.06.001","article-title":"Lambing rates and litter size following carazolol administration prior to insemination in Kivircik ewes","volume":"118","author":"G\u00fcnd\u00fcz","year":"2010","journal-title":"Anim Reprod Sci"},{"key":"B2","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1016\/j.theriogenology.2018.07.005","article-title":"Evaluating reproductive performance of three estrus syn-chronization protocols in Ghezel ewes","volume":"122","author":"Hasani","year":"2018","journal-title":"Theriogenology"},{"key":"B3","doi-asserted-by":"publisher","first-page":"1617","DOI":"10.1007\/s11250-019-02159-8","article-title":"The effect of medroxyprogesterone acetate with or without eCG on conception rate of fat-tail ewes in out of breeding season","volume":"52","author":"Garoussi","year":"2020","journal-title":"Trop Anim Health Prod"},{"key":"B4","doi-asserted-by":"publisher","first-page":"466","DOI":"10.1080\/09712119.2015.1091350","article-title":"Estrus synchronization schemes and application efficacies in anestrus lanzhou fat-tailed ewes","volume":"44","author":"Wei","year":"2016","journal-title":"J Appl Anim Res"},{"key":"B5","doi-asserted-by":"publisher","first-page":"1545","DOI":"10.1007\/s11250-019-01841-1","article-title":"The reused progesterone device has the same effect on short or long estrus synchronization protocols in tropical sheep","volume":"51","author":"Biehl","year":"2019","journal-title":"Trop Anim Health Prod"},{"key":"B6","doi-asserted-by":"publisher","first-page":"469","DOI":"10.1007\/s11250-014-0735-x","article-title":"Estrus synchronization and fixed-time artificial insemination in sheep under field conditions of a semi-arid tropical region","volume":"47","author":"De","year":"2015","journal-title":"Trop Anim Health Prod"},{"key":"B7","doi-asserted-by":"publisher","first-page":"106191","DOI":"10.1016\/j.anireprosci.2019.106191","article-title":"Evaluation of estrous synchronization protocols on ewe reproductive efficiency and profitability","volume":"210","author":"Rosasco","year":"2019","journal-title":"Anim Reprod Sci"},{"key":"B8","doi-asserted-by":"publisher","first-page":"115","DOI":"10.1556\/AVet.2012.010","article-title":"Artificial insemination of small ruminants - a review","volume":"60","author":"Faigl","year":"2012","journal-title":"Acta Vet Hung"},{"key":"B9","doi-asserted-by":"publisher","first-page":"803","DOI":"10.21451\/1984-3143-AR2018-0129","article-title":"Technical recommendations for artificial insemination in sheep","volume":"16","author":"Gibbons","year":"2019","journal-title":"Anim Reprod"},{"key":"B10","doi-asserted-by":"publisher","first-page":"777","DOI":"10.1111\/rda.13683","article-title":"Effect of environmental factors on estrus synchronization and artificial insemination success in farmers flock in sheep under semi-arid tropical region","volume":"55","author":"De","year":"2020","journal-title":"Reprod Domest Anim"},{"key":"B11","doi-asserted-by":"publisher","first-page":"433","DOI":"10.4142\/jvs.2014.15.3.433","article-title":"Effects of progestagen exposure duration on estrus synchronization and conception rates of crossbreed ewes undergoing fixed time artificial insemination","volume":"15","author":"Blaschi","year":"2014","journal-title":"J Vetsci"},{"key":"B12","doi-asserted-by":"publisher","first-page":"1213","DOI":"10.3390\/biology10111213","article-title":"Impact of cryopreservation on motile subpopulations and tyrosine-phosphorylated regions of ram spermatozoa during capacitating conditions","volume":"10","author":"Peris-Frau","year":"2021","journal-title":"Biology"},{"key":"B13","doi-asserted-by":"publisher","first-page":"219","DOI":"10.1080\/09064702.2019.1674373","article-title":"Estrous synchronization in ewes: the use of progestogens and prostaglandins","volume":"68","author":"Yu","year":"2018","journal-title":"Acta Agr Scand"},{"key":"B14","doi-asserted-by":"publisher","first-page":"125","DOI":"10.1016\/j.cvfa.2020.10.007","article-title":"Estrus synchronization in the sheep and goat","volume":"37","author":"Habeeb","year":"2021","journal-title":"Vet Clin North Am Food Anim Pract"},{"key":"B15","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3390\/ani9010009","article-title":"Influence of progesterone-treatment length and eCG administration on appearance of estrus behavior, ovulatory success and fertility in sheep","volume":"9","author":"Martinez-Ros","year":"2019","journal-title":"Animals"},{"key":"B16","first-page":"41","article-title":"Estrous and fertility responses of dairy ewes synchronized with combined short term GnRH, PGF2\u03b1 and estradiol benzoate treatments","volume-title":"Small Ruminant Res","author":"Martemucci","year":"2010"},{"key":"B17","doi-asserted-by":"publisher","first-page":"33","DOI":"10.18805\/ijar.B-646","article-title":"The effects of short-mid-long term intravaginal sponge application on reproductive performance of karacabey Merino ewes in the anestrous season","volume":"1","author":"Altin\u00e7eki\u00e7","year":"2019","journal-title":"Indian Anim Res"},{"key":"B18","doi-asserted-by":"publisher","first-page":"1501","DOI":"10.1016\/j.theriogenology.2011.06.020","article-title":"Alternatives to improve a prostaglandin-based protocol for timed artificial insemination in sheep","volume":"76","author":"Olivera-Muzante","year":"2011","journal-title":"Theriogenology"},{"key":"B19","doi-asserted-by":"publisher","first-page":"163","DOI":"10.1016\/j.theriogenology.2016.12.003","article-title":"Time of ovulation and pregnancy outcomes obtained with the prostaglandin-based protocol Synchrovine for FTAI in sheep","volume":"90","author":"Vilari\u00f1o","year":"2017","journal-title":"Theriogenology"},{"key":"B20","doi-asserted-by":"publisher","first-page":"74","DOI":"10.1016\/j.anireprosci.2016.02.009","article-title":"Concentrations of steroid hormones, estrous, ovarian and reproductive responses in sheep estrous synchronized with different prostaglandin-based protocols","volume":"167","author":"Fierro","year":"2016","journal-title":"Anim Reprod Sci"},{"key":"B21","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1016\/j.theriogenology.2016.11.031","article-title":"Long term prostaglandin based-protocols improve the reproductive performance after timed artificial insemination in sheep","volume":"90","author":"Fierro","year":"2017","journal-title":"Theriogenology"},{"key":"B22","doi-asserted-by":"publisher","first-page":"120","DOI":"10.1016\/j.theriogenology.2017.06.005","article-title":"Progesterone concentration and lambing rate of Karakul ewes treated with prostaglandin and GnRH combined with the ram effect during breeding and non-breeding seasons","volume":"100","author":"Mirzaei","year":"2017","journal-title":"Theriogenology"},{"key":"B23","doi-asserted-by":"publisher","first-page":"78","DOI":"10.1016\/j.anireprosci.2019.05.011","article-title":"Short-term dietary protein supplementation improves reproductive performance of estrous-synchronized ewes when there are long intervals of prostaglandin or progesterone-based treatments for timed AI","volume":"206","author":"Olivera-Muzante","year":"2019","journal-title":"Anim Reprod Sci"},{"key":"B24","doi-asserted-by":"publisher","first-page":"594","DOI":"10.1111\/j.1439-0531.2008.01309.x","article-title":"Estrus synchronization in sheep and goats using combinations of GnRH, progestagen and prostaglandin F2alpha","volume":"45","author":"Titi","year":"2010","journal-title":"Reprod Domest Anim"},{"key":"B25","doi-asserted-by":"publisher","first-page":"545","DOI":"10.1007\/s11250-015-0989-y","article-title":"Efficiency of different hormonal treatments for estrus synchronization in tropical Santa In\u00eas sheep","volume":"48","author":"Texeira","year":"2016","journal-title":"Trop Anim Health Prod"},{"key":"B26","doi-asserted-by":"publisher","first-page":"317","DOI":"10.1016\/j.anireprosci.2018.08.046","article-title":"Effects of short-term intravaginal pro-gestagens on the onset and features of estrus, preovulatory LH surge and ovulation in sheep","volume":"197","author":"Martinez-Ros","year":"2018","journal-title":"Anim Reprod Sci"},{"key":"B27","doi-asserted-by":"publisher","first-page":"280","DOI":"10.1016\/j.anireprosci.2005.08.002","article-title":"Administration of 6-methoxybenzoxazolinone (MBOA) does not augment ovulatory responses in St. Croix White ewes superovulated with PMSG","volume":"93","author":"Willard","year":"2006","journal-title":"Anim Reprod Sci"},{"key":"B28","doi-asserted-by":"publisher","first-page":"965","DOI":"10.1007\/s11250-011-9993-z","article-title":"Reproductive performance in out-of-breeding season of fatty ewes using implant norgestomet with or without PMSG","volume":"44","author":"Talebkhan Garoussi","year":"2012","journal-title":"Trop Anim Health Prod"},{"key":"B29","doi-asserted-by":"publisher","first-page":"386","DOI":"10.1016\/j.tem.2007.09.005","article-title":"LHRH-(1-5): a bioactive peptide regulating reproduction","volume":"18","author":"Roberts","year":"2007","journal-title":"Trends Endocrinol Metab"},{"key":"B30","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1071\/rd9940247","article-title":"Superovulation and embryo recovery in ewes treated with gonadotro-phin-releasing hormone agonist and purified follicle-stimulating hormone","volume":"6","author":"Evans","year":"1994","journal-title":"Reprod Fertil Dev"},{"key":"B31","doi-asserted-by":"publisher","first-page":"146","DOI":"10.3390\/ani9040146","article-title":"Efficiency of CIDR-based protocols including GnRH instead of eCG for estrus synchronization in sheep","volume":"9","author":"Martinez-Ros","year":"2019","journal-title":"Animals"},{"key":"B32","article-title":"Skimmed milk diluent promotes the sperm motility and conception rate of Dorper sheep compared to vitamin B12 diluent","volume-title":"CryoLetters","author":"Bai","year":"2020"},{"key":"B33","doi-asserted-by":"publisher","first-page":"32","DOI":"10.1016\/j.anireprosci.2010.11.007","article-title":"Synchronization of oestrus and ovulation by short time combined FGA, PGF(2\u03b1), GnRH, eCG treatments for natural service or AI fixed-time","volume":"123","author":"Martemucci","year":"2011","journal-title":"Anim Reprod Sci"},{"key":"B34","doi-asserted-by":"publisher","first-page":"498","DOI":"10.1016\/j.theriogenology.2015.03.018","article-title":"Use of fluorogestone acetate sponges or controlled internal drug release for estrus synchronization in ewes: Effects of hormonal profiles and reproductive performance","volume":"84","author":"Swelum","year":"2015","journal-title":"Theriogenology"},{"key":"B35","doi-asserted-by":"publisher","first-page":"1567","DOI":"10.1007\/s11250-011-9843-z","article-title":"The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes","volume":"43","author":"Quintero-Elisea","year":"2011","journal-title":"Trop Anim Health Prod"},{"key":"B36","doi-asserted-by":"publisher","first-page":"34","DOI":"10.1016\/j.anireprosci.2018.02.002","article-title":"Factors affecting differences between birth weight of littermates (BWTD) and the effects of BWTD on lamb performance","volume":"191","author":"Juengel","year":"2018","journal-title":"Anim Reprod Sci."},{"key":"B37","doi-asserted-by":"publisher","first-page":"117","DOI":"10.1016\/j.anireprosci.2004.03.005","article-title":"Induction of estrus in non-lactating dairy goats with different estrous synchrony protocols","volume":"85","author":"Fonseca","year":"2005","journal-title":"Anim Reprod Sci"},{"key":"B38","doi-asserted-by":"publisher","first-page":"23","DOI":"10.3844\/ajavsp.2007.23.28","article-title":"The effects of short or long term FGA treatment with or without eCG on reproductive performance of ewes bred out-of-season","volume":"2","author":"Husein","year":"2007","journal-title":"Am J Anim Vet Sci"},{"key":"B39","doi-asserted-by":"publisher","first-page":"119","DOI":"10.1071\/RDv29n1Ab23","article-title":"23 The effect of withdrawal timing of controlled internal drug release (CIDR) on ewe reproductive performance","volume":"29","author":"Swelum","year":"2017","journal-title":"Reprod Fert Develop"},{"key":"B40","doi-asserted-by":"publisher","first-page":"1796","DOI":"10.1016\/j.theriogenology.2012.07.001","article-title":"Intravaginal sponges to synchronize estrus decrease sexual attractiveness in ewes","volume":"78","author":"Gatti","year":"2012","journal-title":"Theriogenology"},{"key":"B41","doi-asserted-by":"publisher","first-page":"719","DOI":"10.3390\/ani10040719","article-title":"Use of probiotics in intravaginal sponges in sheep: a pilot study","volume":"10","author":"Quereda","year":"2020","journal-title":"Animals"},{"key":"B42","doi-asserted-by":"crossref","DOI":"10.1007\/s00580-017-2542-z","article-title":"Influence of a device intravaginal to synchronization\/induction of estrus and its reuse in sheep vaginal flora","volume-title":"Comp Clin Pathol","author":"Bragan\u00e7a","year":"2017"},{"key":"B43","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1111\/rda.12482","article-title":"Vaginal histological changes after using intravaginal sponges for oestrous synchronization in anoestrous ewes","volume":"50","author":"Manes","year":"2015","journal-title":"Reprod Domest Anim"},{"key":"B44","doi-asserted-by":"publisher","first-page":"226","DOI":"10.3390\/ani8120226","article-title":"Intravaginal device-type and treatment-length for ovine estrus synchronization modify vaginal mucus and microbiota and affect fertility","volume":"8","author":"Martinez-Ros","year":"2018","journal-title":"Animals"},{"key":"B45","doi-asserted-by":"publisher","first-page":"141","DOI":"10.3168\/jds.2015-10200","article-title":"Short communication: Drug residues in goat milk after prophylactic use of antibiotics in intravaginal sponges for estrus synchronization","volume":"99","author":"Romero","year":"2016","journal-title":"J Dairy Sci"},{"key":"B46","doi-asserted-by":"publisher","first-page":"565","DOI":"10.1071\/AN1020","article-title":"Pregnancy rate and prolificacy after artificial insemination in ewes following synchronization with prostaglandin, sponges or sponges with bactericide","volume":"51","author":"Vi\u00f1oles","year":"2011","journal-title":"Anim Prod Sci"}],"container-title":["Frontiers in Veterinary Science"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fvets.2022.843514\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,6]],"date-time":"2022-04-06T07:38:01Z","timestamp":1649230681000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fvets.2022.843514\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,5]]},"references-count":46,"alternative-id":["10.3389\/fvets.2022.843514"],"URL":"https:\/\/doi.org\/10.3389\/fvets.2022.843514","relation":{},"ISSN":["2297-1769"],"issn-type":[{"value":"2297-1769","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,5]]},"article-number":"843514"}}