Camacho L E, Lemley C O, Prezotto L D, Bauer M L, Freetly H C, Swanson K C, Vonnahme K A
Department of Animal Sciences, North Dakota State University, Fargo, North Dakota, USA.
USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA.
Theriogenology. 2014 Jun;81(9):1248-56.e1-3. doi: 10.1016/j.theriogenology.2014.02.006. Epub 2014 Feb 15.
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.
目的是研究妊娠中期母体营养限制后再恢复营养对子宫血流量（BF）的影响。在妊娠第30天，将处于泌乳期的经产西门塔尔肉牛随机分配至各处理组：对照组（CON；100%美国国家研究委员会标准；n = 6）和营养限制组（RES；CON组的60%；n = 4），从第30天至140天（第1阶段）进行营养限制，之后恢复至CON组水平直至妊娠第198天（第2阶段）。通过多普勒超声从同侧和对侧子宫动脉获取子宫BF、搏动指数（PI）和阻力指数（RI）。进行广义最小二乘法分析。两组同侧子宫BF在第1阶段呈二次方增加（P < 0.01），在第2阶段呈线性增加（P < 0.01）。在第2阶段存在处理效应（P = 0.05）；RES组母牛同侧BF高于CON组。在第1阶段，各处理组同侧子宫PI和RI均呈线性下降（P≤0.01）。在两个阶段，CON组母牛对侧子宫BF均倾向于高于RES组（P < 0.09）。在第1阶段，两组对侧PI均呈线性增加（P≤0.01）。在两个阶段，RES组母牛对侧子宫RI均高于CON组（P≤0.05）。在任一阶段，总BF均无交互作用或处理效应（P≥0.24）。营养限制不会改变子宫总BF，但可能增加血管阻力。然而，恢复营养后，局部源自孕体的血管活性因子似乎会影响同侧子宫BF。
