{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T00:56:52Z","timestamp":1775005012196,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T00:00:00Z","timestamp":1752796800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Agricultural, Food and Forestry Policies, MASAF, Measure 10.2 Biodiversity\u2014Rabbit sector","award":["0120987"],"award-info":[{"award-number":["0120987"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>The cryopreservation of rabbit semen is a valuable strategy for genetic resource preservation and efficient artificial insemination, but outcomes remain inconsistent, partly due to variations in sperm concentration per dose. This study aimed to evaluate the in vivo effects of different sperm concentrations (15, 25, 35, 55, and 75 million per straw) on fertility, prolificacy, and offspring growth in nulliparous and multiparous does. A total of 384 rabbit females were inseminated using frozen\u2013thawed semen, and their reproductive performance was compared with fresh semen. Fertility and kindling rates varied with sperm concentration and parity: nulliparous does showed the highest fertility at 15 million sperm\/straw (84.4%), while multiparous does reached peak values at 25\u201355 million\/straw (78.1\u201381.3%). Litter size and live-born kits were consistently higher in multiparous than in nulliparous does. Offspring body weight at 19 and 60 days was influenced by both sperm concentration and maternal parity, with better growth generally observed in multiparous groups. Weaning success remained high across all groups. Our results indicate that sperm concentrations ranging from 15 to 35 \u00d7 106\/straw are the most suitable for cryopreservation, as they maintain high fertility, prolificacy, and offspring growth, comparable to fresh semen. These results confirm that optimizing sperm concentration during cryopreservation improves reproductive efficiency and that tailoring insemination strategies to the physiological status of the female enhances outcomes. The results provide useful recommendations for improving cryopreservation techniques in rabbit breeding programs.<\/jats:p>","DOI":"10.3390\/vetsci12070678","type":"journal-article","created":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T12:09:53Z","timestamp":1752840593000},"page":"678","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Validating Sperm Concentration in Rabbit Cryopreservation Protocol: Implications for Fertility, Litter Size, and Offspring Growth"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7454-4970","authenticated-orcid":false,"given":"Michele","family":"Di Iorio","sequence":"first","affiliation":[{"name":"Department of Agricultural, Environmental and Food Sciences, University of Molise, Via De Sanctis snc, 86100 Campobasso, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8300-9286","authenticated-orcid":false,"given":"Giusy","family":"Rusco","sequence":"additional","affiliation":[{"name":"Department of Agricultural, Environmental and Food Sciences, University of Molise, Via De Sanctis snc, 86100 Campobasso, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-5518-2613","authenticated-orcid":false,"given":"Fabrizio","family":"Lauriola","sequence":"additional","affiliation":[{"name":"Department of Agricultural, Environmental and Food Sciences, University of Molise, Via De Sanctis snc, 86100 Campobasso, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emanuele","family":"Antenucci","sequence":"additional","affiliation":[{"name":"Department of Agricultural, Environmental and Food Sciences, University of Molise, Via De Sanctis snc, 86100 Campobasso, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8926-3362","authenticated-orcid":false,"given":"Alessandra","family":"Roncarati","sequence":"additional","affiliation":[{"name":"School of Biosciences and Veterinary Medicine, University of Camerino, Via Circonvallazione 93\/95, 62024 Matelica, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5625-0357","authenticated-orcid":false,"given":"Silvia","family":"Cerolini","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine and Animal Science, University of Milan, Via dell\u2019Universit\u00e0 6, 26900 Lodi, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michele","family":"Schiavitto","sequence":"additional","affiliation":[{"name":"Italian Rabbit Breeders Association (ANCI-AIA), Volturara Appula, 71030 Foggia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9680-1264","authenticated-orcid":false,"given":"Nicolaia","family":"Iaffaldano","sequence":"additional","affiliation":[{"name":"Department of Agricultural, Environmental and Food Sciences, University of Molise, Via De Sanctis snc, 86100 Campobasso, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.anireprosci.2008.08.015","article-title":"Rabbit sperm cryopreservation: A review","volume":"110","author":"Vicente","year":"2009","journal-title":"Anim. 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