title: The effect of feeding propylene glycol to dairy cows during the early postpartum period on follicular dynamics and on metabolic parameters related to fertility.
abstract: Postpartum dairy cows (n=35) were used to determine the effects of feeding propylene glycol (PG) on metabolic variables related to ovarian function and on oocyte developmental competence. Starting on Day 7 postpartum, each animal received an oral dose (500 ml) of either PG or water once daily. Blood samples were collected on Days 5, 15, 25 and 35 pp to measure insulin, non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHB) and glucose concentrations. Oocytes were recovered by ultrasound guided follicular aspiration starting on approximately Day 30 postpartum and submitted to in vitro fertilization. Ovarian follicular activity was examined daily by ultrasonography from Day 7 until ovulation or Days 35-40 postpartum. Animals receiving PG had elevated insulin concentrations over the subsequent 90 min following dosing (P<0.05) compared to control animals. Glucose concentrations followed a similar pattern. Irrespective of treatment, concentrations of NEFA declined significantly from Days 15 to 35 postpartum. Administration of PG resulted in a decrease in NEFA (P<0.001) and BHB (P<0.001) over the subsequent 90 min compared to control animals. Treatment with PG had no effect on follicular dynamics, mean days to emergence of the first cohort of follicles postpartum, or days to dominance and duration of dominance for any follicular wave recorded postpartum. There was also no difference in mean days to first ovulation or in size of the preovulatory follicle between treatments. Oocyte quality as measured by blastocyst development after IVF was not affected by treatment. These results suggest that administration of PG has the ability to positively alter the systemic concentrations of a number of metabolic variables which have been related to fertility. However, we did not observe an effect of PG treatment on follicular dynamics or the length of the postpartum interval. An effect on oocyte developmental competence remains to be proven.
authors.affiliation: School of Agriculture, Food Science and Veterinary Medicine, College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Rizos
authors.forename: D A
authors.initials: DA
authors.lastname: Kenny
authors.forename: W
authors.initials: W
authors.lastname: Griffin
authors.forename: K M
authors.initials: KM
authors.lastname: Quinn
authors.forename: P
authors.initials: P
authors.lastname: Duffy
authors.forename: F J
authors.initials: FJ
authors.lastname: Mulligan
authors.forename: J F
authors.initials: JF
authors.lastname: Roche
authors.forename: M P
authors.initials: MP
authors.lastname: Boland
authors.forename: P
authors.initials: P
authors.lastname: Lonergan
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002417:Cattle / Q000502:physiology*; D004032:Diet; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005298:Fertility / Q000187:drug effects* / Q000502:physiology; D005307:Fertilization in Vitro / Q000662:veterinary; D007328:Insulin / Q000097:blood; D007774:Lactation / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development; D006080:Ovarian Follicle / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D049590:Postpartum Period / Q000187:drug effects / Q000502:physiology; D019946:Propylene Glycol / Q000008:administration & dosage*; D014463:Ultrasonography
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019946:Propylene Glycol; D020155:3-Hydroxybutyric Acid