title: Relation of reproductive performances and rectal palpation for luteum function of heifers 7 days after estrus.
abstract: Diagnosis of corpus luteum (CL) function by rectal palpation (RP) has been widely used for recipient selection of embryo transfer (ET), a technology essential for genetic improvements in cattle. To examine the accuracy of RP diagnosis method, the relationship between RP-based CL function and reproductive performance was compared in this study. In Experiment 1, CL of Holstein heifers on day 7 after estrus was classified into functional or hypoplastic by RP, and the results were compared with ultrasonographic (US) images and plasma progesterone (P4) levels. As a result, heifers with functional CL judged by RP had a mean maximum CL diameter of 20.1 ± 3.1 mm on US and a mean P4 concentration of 8.1 ± 2.3 ng/mL. These values were significantly greater than those of heifers with hypoplastic CL (12.4 ± 5.4 mm, 4.0 ± 2.8 ng/mL) (P < 0.001). In Experiment 2, the length of the estrus cycle was examined between functional CL and hypoplastic CL. The rate of heifers with a normal estrus cycle length with 18-25 days was significantly lower with hypoplastic CL than with functional CL (16/24 vs. 43/46, P < 0.01). In Experiment 3, 543 inseminated heifers were similarly classified by CL function by RP 7 days after estrus. The heifers with functional CL showed higher pregnancy rate compared with the heifers with hypoplastic CL (75.2 vs. 47.9%, P < 0.0001). Finally, the CL function of 66 heifers was examined by RP on day 7 post-estrus, and ET was performed in 49 (74.2%) heifers with functional CL. As a result, 27 (55.1%) of them became pregnant. Taken together, these results reconfirm that RP on day 7 after estrus is useful for selection of heifers with functional CL.
authors.affiliation: Department of Animal Science, Nippon Veterinary and Life Science University, Musashino, Japan.
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Yoshida
authors.forename: Makoto
authors.initials: M
authors.lastname: Seki
authors.forename: Norio
authors.initials: N
authors.lastname: Watanabe
authors.forename: Hiroki
authors.initials: H
authors.lastname: Furuta
authors.forename: Itaru
authors.initials: I
authors.lastname: Yoshimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Osada
authors.forename: Koji
authors.initials: K
authors.lastname: Chiba
authors.forename: Konosuke
authors.initials: K
authors.lastname: Okada
authors.forename: Koh
authors.initials: K
authors.lastname: Kawasumi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ushijima
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D003338:Corpus Luteum / Q000502:physiology*; D004624:Embryo Transfer / Q000662:veterinary; D004971:Estrus / Q000502:physiology; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D010173:Palpation / Q000662:veterinary*; D012007:Rectum / Q000502:physiology*