{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T12:16:23Z","timestamp":1753877783821,"version":"3.41.2"},"reference-count":23,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2021,4,7]],"date-time":"2021-04-07T00:00:00Z","timestamp":1617753600000},"content-version":"vor","delay-in-days":6,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,4,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>To determine effects of delaying the injection of prostaglandin F2\u03b1 (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG protocol, 1,049 Angus heifers at six locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to one of two treatment groups: 1) PG16 (n = 518), heifers received a controlled internal drug release (CIDR) insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal (d 30), and a 100-\u00b5g injection of gonadotropin-releasing hormone concurrent with TAI 66 \u00b1 2 h later; or 2) PG17 (n = 531), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal (d 31), and heifers were TAI 66 \u00b1 2 h later. Estrus detection patches were applied to a subset (n = 482) of heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 116). Transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR\/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI differed by treatment where PG17 heifers had greater (P &amp;lt; 0.01) expression of estrus than PG16 heifers (57.8 \u00b1 6.1% vs. 43.4 \u00b1 6.1%, respectively). Nevertheless, dominant follicle diameters at PGF and at TAI were similar (P \u2265 0.59) between PG16 and PG17 heifers. In addition, PR\/AI did not differ (P = 0.29) between PG16 and PG17 treatments (50.5 \u00b1 3.2% vs. 45.7 \u00b1 3.1%, respectively). Results of this experiment indicate that delaying the injection of PGF and TAI in the 14-d CIDR-PG protocol increased estrus expression prior to TAI yet did not improve fertility in beef heifers.<\/jats:p>","DOI":"10.1093\/tas\/txab062","type":"journal-article","created":{"date-parts":[[2021,4,7]],"date-time":"2021-04-07T15:49:01Z","timestamp":1617810541000},"source":"Crossref","is-referenced-by-count":0,"title":["Effects of prolonging the interval from progestin removal to prostaglandin F2\u03b1 injection from 16 to 17 d in a long-term estrus synchronization protocol in beef heifers"],"prefix":"10.1093","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1904-5770","authenticated-orcid":false,"given":"Nicola","family":"Oosthuizen","sequence":"first","affiliation":[{"name":"Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gabriela D","family":"Melo","sequence":"additional","affiliation":[{"name":"Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"George E","family":"Seidel","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R Lawton","family":"Stewart","sequence":"additional","affiliation":[{"name":"Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Larry","family":"Rowden","sequence":"additional","affiliation":[{"name":"ABS Global, Broken Bow, NE 68822, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8130-3617","authenticated-orcid":false,"given":"Graham C","family":"Lamb","sequence":"additional","affiliation":[{"name":"Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1369-5641","authenticated-orcid":false,"given":"Pedro L P","family":"Fontes","sequence":"additional","affiliation":[{"name":"Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2021,4,7]]},"reference":[{"year":"2021","author":"Beef Reproductive Task Force","key":"2021070809514485800_CIT0001"},{"key":"2021070809514485800_CIT0002","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0093-691X(88)90258-0","article-title":"Comparison of melengestrol acetate-prostaglandin F(2)alpha to Syncro-Mate B for estrus synchronization in beef heifers","volume":"30","author":"Brown","year":"1988","journal-title":"Theriogenology"},{"key":"2021070809514485800_CIT0003","doi-asserted-by":"crossref","first-page":"4486","DOI":"10.2527\/jas.2013-6465","article-title":"Heifer calving date positively influences calf weaning weights through six parturitions","volume":"91","author":"Cushman","year":"2013","journal-title":"J. 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