title: Pregnancy development from day 28 to 42 of gestation in postpartum Holstein cows that were either milked (lactating) or not milked (not lactating) after calving.
abstract: The objective was to determine if lactation affects fetal and placental development from day 28 to 42 of gestation. Bos taurus Holstein cows were assigned to one of the two treatments immediately after parturition (lactating (n=23) or nonlactating (dried off immediately after calving; n=20)). Cows were inseminated at ~60 days postpartum with semen from a single ejaculate. Pregnant cows were slaughtered at 1 of 3 days of gestation (day 28, 35, or 42) and tissues were collected. The interval to first insemination, services per conception, and days to pregnancy were similar for lactating and nonlactating cows. Lactating cows had greater plasma GH and nonesterified fatty acids. Nonlactating cows had greater plasma glucose, insulin, and IGF1. There was no effect of lactation on plasma progesterone or estradiol concentrations. Lactation had a negative effect on the weight of the fetus and placenta (weights were less in lactating cows). Fetuses collected from cows that became pregnant after first insemination were heavier than fetuses collected from cows that became pregnant after second or third insemination. Pregnancy after first insemination was associated with greater blood glucose and IGF1 during the first 30 days postpartum. The conclusions were that lactation negatively affects the growth of fetal and placental tissues perhaps through a mechanism that involves hormones and metabolites that are affected by lactation. Fetal growth within cows conceiving at first insemination compared to second or third insemination was more rapid and was associated with greater blood glucose and IGF1 early postpartum (before day 30).
authors.affiliation: Division of Animal Sciences, 158 Animal Science Research Center, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Green
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Meyer
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Williams
authors.forename: Emily M
authors.initials: EM
authors.lastname: Newsom
authors.forename: Duane H
authors.initials: DH
authors.lastname: Keisler
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Lucy
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002417:Cattle; D003338:Corpus Luteum / Q000254:growth & development / Q000378:metabolism; D004958:Estradiol / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D047109:Fetal Development; D020567:Fetal Weight; D005865:Gestational Age; D013006:Growth Hormone / Q000097:blood; D007315:Insemination, Artificial / Q000662:veterinary; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007774:Lactation / Q000097:blood; D010920:Placenta / Q000378:metabolism; D010929:Placentation; D049590:Postpartum Period / Q000097:blood; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood; D011374:Progesterone / Q000097:blood; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011257:Pregnancy Proteins; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone