Periparturient endocrine changes of conceptus and maternal units in Holstein heifers bearing genetically different conceptuses.

摘要: Holstein heifers (n = 21) were balanced across sires and assigned to three service-sire-breed groups in which inseminated artificially either purebred Angus 7), 7) or Brahman bulls. Semen from four bulls was used for each service sire-breed group. Blood samples collected a jugular vein thrice weekly d 160 265 of pregnancy, daily thereafter until 15 postpartum, then 60 postpartum. Concentrations progesterone, estrone, estradiol, estrone sulfate 23 prepartum parturition, 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) 2 postpartum measured by radioimmunoassay. Heifers within the Brahman-service-sire group had longer gestations (P less than .05) those Holstein- Angus-service-sire (285.0 vs 278.7), 279.0 d). Calf birth weight lower Angus- (30.6 36.1, 43.4 kg). Daily trends maternal progesterone concentrations approximately 1 ng/ml .01) luteolysis occurred. bearing crossbred conceptuses estrogens .01), whereas and, even more dramatically, higher magnitude greater rise plasma between -10 -1 (less .01). Postpartum mean response curves PGFM groups. weights correlated with least-squares means (r .57), estradiol .59) .64) .56). Functional responses conceptus (e.g., estrogens) units PGFM) influenced genotype during periparturient period.