title: Ultrasonography and progesterone concentration at a single time point for the detection of puberty in dairy heifers.
abstract: Data were available from 1657 heifers across 48 dairy farms which were visited once, on average 9 days (± 5.2) prior to the mating start date (23 April, ± 12.6). Blood samples were collected via coccygeal venepuncture for progesterone (P4) analysis, and animals were scanned for the presence or absence of corpora lutea (CL), to determine the luteal status. A comparison of luteal status between ultrasound (CL identified) and P4 (≥ 1 ng/ml), based on a single measurement point, showed poor agreement (K = 0.32). The majority of animals were classified as luteal (76%) using both ultrasonography and P4. There was excellent agreement between luteal status detected by ultrasonography alone and luteal status assigned by a combination of ultrasonography and P4 (K = 0.93). The agreement between luteal status assigned by P4 and luteal status assigned by the combination of ultrasonography and P4 was poor (K = 0.37). These results indicate that at a single examination, ultrasonography is the preferred modality to determine the luteal status of maiden heifers.
authors: Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, County Cork, Ireland.
authors: H
authors: H
authors: Archbold
authors: F
authors: F
authors: Buckley
authors: K M
authors: KM
authors: Pierce
authors: N
authors: N
authors: Begley
authors: J F
authors: JF
authors: Mee
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D003612:Dairying; D005260:Female; D010053:Ovary / Q000000981:diagnostic imaging*; D011374:Progesterone / Q000097:blood*; D012741:Sexual Maturation / Q000502:physiology*; D014463:Ultrasonography
chemical_list: D011374:Progesterone