title: Effect of serial blood sampling on interpretation of estradiol-17 beta involvement in laying hen calcium metabolism.
abstract: Effects of long-term, low levels of exogenous estradiol-17 beta and dietary calcium on calcium metabolism and laying hen performance, and effects of serial blood-sampling, were studied. Significant 3-way (P less than 0.01) and 2-way (P less than 0.05) interactions involving sampling obscured possible main effects (Exp. 1); no main effects were found in absence of blood sampling (Exp. 2). Estradiol-17 beta appears to increase calcium utilization with very low dietary calcium only. Relatively small brachial vein samples taken only every 3-4 weeks have substantial confounding effects on interpretation of data.
mesh_terms: D000818:Animals; D001800:Blood Specimen Collection; D002118:Calcium / Q000378:metabolism*; D002645:Chickens; D004032:Diet; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D010058:Oviposition / Q000187:drug effects
chemical_list: D004958:Estradiol; D002118:Calcium