{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T23:41:42Z","timestamp":1767915702450,"version":"3.49.0"},"reference-count":0,"publisher":"Oxford University Press (OUP)","issue":"1","license":[{"start":{"date-parts":[[1979,9,1]],"date-time":"1979-09-01T00:00:00Z","timestamp":304992000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":["reproduction-online.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1979,9,1]]},"abstract":"<jats:p>Summary. The XX lymphocytes in peripheral blood of 22 bulls born co-twin with freemartins ranged from 5 to 95%. The difference of 1\u00b72% between the means of XX percentages at initial and final karyotyping of 14 bulls over periods of 1\u20135 years was not significant (P &amp;gt; 0\u00b725). Seven (58\u00b73%) of the 12 A.I. chimaeric bulls were reproductive culls as compared to only 5\u00b74% of their 128 controls (P &amp;lt; 0\u00b7001). The culled chimaeras produced no semen, had a low sperm output or had a high incidence of abnormal spermatozoa. The means for motility, sperm concentration and motile spermatozoa per ejaculate were significantly lower for the 12 chimaeric bulls than for a random sample of 12 controls (P &amp;lt; 0\u00b7025). The 60- to 90-day non-return rate for 30 814 services to 8 chimaeric bulls was 70% with a \u22120\u00b71% mean deviation from contemporary breed average (P &amp;gt; 0\u00b75).<\/jats:p>\n                  <jats:p>The 7 chimaeric bulls culled for poor reproductive performance had larger and more numerous focal areas of testicular degeneration. Areas of lymphocytic infiltration in testes of many of these bulls suggest a rejection phenomenon or the autoimmune response. No XX germ cells were detected in testes of 11 chimaeric bulls, aged 1\u20139 years. Differential haemolysis blood typing tests on one bull with 85% XX lymphocytes and 23 of his dam\u2014daughter pairs provided no evidence of germ cell chimaerism. One bull with 33% XX cells sired an excess of daughters (71%) in a progeny group of 48, a significant deviation from a 1:1 ratio (P &amp;lt; 0\u00b701).<\/jats:p>\n                  <jats:p>A disturbance in normal spermatogenesis in prenatal and postnatal life by transplanted XX primordial germ cells may contribute to the marked reduction in reproductive fitness of many chimaeric bulls.<\/jats:p>","DOI":"10.1530\/jrf.0.0570021","type":"journal-article","created":{"date-parts":[[2004,3,20]],"date-time":"2004-03-20T03:12:46Z","timestamp":1079752366000},"page":"21-30","update-policy":"https:\/\/doi.org\/10.1530\/rep\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":38,"title":["Cytogenetic and reproductive studies of bulls born co-twin with freemartins"],"prefix":"10.1093","volume":"57","author":[{"given":"H. O.","family":"Dunn","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K.","family":"McEntee","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C. E.","family":"Hall","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"Jr","given":"R. H.","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"W. H.","family":"Stone","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[1979,9,1]]},"container-title":["Reproduction"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/reproduction\/article-pdf\/57\/1\/21\/64933464\/jrf_57_1_004.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/reproduction\/article-pdf\/57\/1\/21\/64933464\/jrf_57_1_004.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T18:16:57Z","timestamp":1767896217000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/reproduction\/article\/57\/1\/21\/8290096"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1979,9,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1979,9,1]]}},"URL":"https:\/\/doi.org\/10.1530\/jrf.0.0570021","relation":{},"ISSN":["1470-1626","1741-7899"],"issn-type":[{"value":"1470-1626","type":"print"},{"value":"1741-7899","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[1979,9,1]]},"published":{"date-parts":[[1979,9,1]]}}}