title: Effects of maternal nutrient restriction followed by realimentation during midgestation on uterine blood flow in beef cows.
abstract: The objective was to examine the effect of maternal nutrient restriction followed by realimentation during midgestation on uterine blood flow (BF). On Day 30 of pregnancy, lactating, multiparous Simmental beef cows were assigned randomly to treatments: control (CON; 100% National Research Council; n = 6) and nutrient restriction (RES; 60% of CON; n = 4) from Day 30 to 140 (period 1), and thereafter, realimented to CON until Day 198 of gestation (period 2). Uterine BF, pulsatility index (PI), and resistance index (RI) were obtained from both the ipsilateral and contralateral uterine arteries via Doppler ultrasonography. Generalized least square analysis was performed. Ipsilateral uterine BF in both groups increased quadratically (P < 0.01) during period 1 and linearly (P < 0.01) during period 2. There was a treatment (P = 0.05) effect during period 2; where RES cows had greater ipsilateral BF versus CON. Ipsilateral uterine PI and RI decreased linearly (P ≤ 0.01) during period 1 across treatments. Contralateral uterine BF in CON cows tended (P < 0.09) to be greater versus RES in both periods. Contralateral PI in both groups increased linearly (P ≤ 0.01) during period 1. Contralateral uterine RI was increased (P ≤ 0.05) in RES cows versus CON in both periods. There was no interaction or treatment effect (P ≥ 0.24) for total BF during either period. Nutrient restriction does not alter total uterine BF, but it may increase vascular resistance. However, up on realimentation, local conceptus-derived vasoactive factors appear to influence ipsilateral uterine BF.
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Camacho
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
authors.forename: C O
authors.initials: CO
authors.lastname: Lemley
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Prezotto
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Bauer
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA.
authors.forename: H C
authors.initials: HC
authors.lastname: Freetly
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
authors.forename: K C
authors.initials: KC
authors.lastname: Swanson
authors.affiliation: Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA. Electronic address: Kim.Vonnahme@ndsu.edu.
authors.forename: K A
authors.initials: KA
authors.lastname: Vonnahme
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D011247:Pregnancy; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color / Q000662:veterinary; D014599:Uterus / Q000098:blood supply*
keywords: Beef cow; Nutrient restriction; Pregnancy; Uterine blood flow