{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:17:36Z","timestamp":1785403056457,"version":"3.56.0"},"reference-count":34,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T00:00:00Z","timestamp":1778544000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Federal Ministry of Agriculture, Food and Regional Identity","award":["281DT01B21"],"award-info":[{"award-number":["281DT01B21"]}]},{"award":["281DT01B21"],"award-info":[{"award-number":["281DT01B21"]}],"id":[{"id":"https:\/\/ror.org\/04jw21793","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background: Antibiotic-free approaches to boar semen preservation are gaining importance to counter emerging antimicrobial resistance. Hypothermic storage at 5 \u00b0C, instead of the conventional 17 \u00b0C, is a promising strategy to eliminate antibiotics still commonly used in extenders. For practical adoption, the method must be simple and compatible with on-farm routines. Objective: To assess fertility when cooling was initiated on farm one day after delivery, and to evaluate the robustness of cold-stored semen to temporary warming and subsequent re-cooling, mimicking typical handling on insemination days. Methods: Individual ejaculates (n = 34) from six boars were extended in Androstar\u00ae Premium either without antibiotics (5 \u00b0C) or with gentamicin (17 \u00b0C control). One day after collection, antibiotic-free doses were cooled on farm to 5 \u00b0C and used alongside controls in routine insemination of 270 sows. Sperm quality was evaluated by computer-assisted semen analysis and flow cytometry, and bacterial counts were monitored. In a separate test, cold-stored doses were exposed to 20 \u00b0C for 60 min and re-cooled to 5 \u00b0C. Results: Farrowing rates and litter sizes did not differ between groups (p &gt; 0.05). In antibiotic-free samples after 120 h, bacterial counts were mostly not detectable or low (&lt;102 CFU\/mL). Sperm motility and plasma membrane integrity in cold-stored doses remained &gt;80%, comparable to controls (p &gt; 0.05). Temporary warming did not affect sperm quality or bacterial counts. Conclusions: Antibiotic-free semen storage at 5 \u00b0C is easy to implement in practice and maintains fertility under field conditions. Broader validation under routine conditions is encouraged in support of the One Health concept.<\/jats:p>","DOI":"10.3390\/antibiotics15050490","type":"journal-article","created":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T10:33:21Z","timestamp":1778841201000},"page":"490","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Antibiotic-Free Hypothermic Storage of Boar Semen at 5 \u00b0C with Next-Day On-Farm Cooling: Fertility and Biosafety Under Field Conditions"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-3318-0754","authenticated-orcid":false,"given":"Florian","family":"Reckinger","sequence":"first","affiliation":[{"name":"Unit for Reproductive Medicine\/Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, B\u00fcnteweg 15, D-30559 Hanover, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5305-2355","authenticated-orcid":false,"given":"Anne-Marie","family":"Luther","sequence":"additional","affiliation":[{"name":"Unit for Reproductive Medicine\/Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, B\u00fcnteweg 15, D-30559 Hanover, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thu Quynh","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Unit for Reproductive Medicine\/Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, B\u00fcnteweg 15, D-30559 Hanover, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anja","family":"Riesenbeck","sequence":"additional","affiliation":[{"name":"GFS Genossenschaft zur F\u00f6rderung der Schweinehaltung eG, Zum P\u00f6pping 29, D-59387 Ascheberg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6616-2035","authenticated-orcid":false,"given":"Dagmar","family":"Waberski","sequence":"additional","affiliation":[{"name":"Unit for Reproductive Medicine\/Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, B\u00fcnteweg 15, D-30559 Hanover, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/S0378-4320(00)00157-3","article-title":"Storage of boar semen","volume":"62","author":"Johnson","year":"2000","journal-title":"Anim. 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