72 Seminal Plasma Uterine Priming Reduces Offspring Growth and Alters Uterine Artery Indices of Vascular Resistance in Embryo-Recipient Beef Cows

Abstract

Abstract Uterine priming with seminal plasma has been shown to alter endometrial gene expression as well as uterine cytokines and chemokines. However, the effects of seminal plasma uterine priming on uterine blood flow, fetal and postnatal offspring growth performance have yet to be elucidated. Therefore, we investigated the effects of pooled seminal plasma uterine priming at estrus on embryo crown-rump length, uterine blood flow, and birth weights. Commercial cows (n = 65) were synchronized, evaluated for standing estrus (day 0), and randomly assigned to treatment groups: seminal plasma or control. Seminal plasma treated cows (n = 27) received 0.5 mL of pooled seminal plasma from commercial bulls mismatched from embryo sire placed in their uterine body via artificial insemination rod2 hours after estrus detection (day 0). Control cows (n = 27) were passed through the chute without receiving treatment. On day 7, cows underwent non-surgical embryo transfer and were confirmed pregnant on day 35 via ultrasonography. Final treatment numbers were n = 9 seminal plasma and n = 7 control. On days 35, 40, and 45 embryo crown-rump length was measured via transrectal ultrasonography. On days 140, 180, 200 and 220, uterine artery hemodynamics were measured via Doppler ultrasonography. Birth weights were collected within 24 hours of birth. Data collected over time were analyzed using repeated measures of ANOVA with fixed effects of treatment, day, and their respective interaction. Birth weights and gestation length were analyzed using ANOVA. Embryo sire and dam, side of pregnancy, and fetal sex were included as covariates if P < 0.10. Covariance structure was selected based on lowest AIC and BIC. Embryo crown-rump length was decreased (P = 0.0483) among seminal plasma treated cows compared with controls. Embryo crown-rump length increased (P < 0.0001) by day. Total uterine blood flow increased (P < 0.0001) as gestation proceeded. Ipsilateral resistance index was increased (P = 0.0431) among seminal plasma treated cows compared with controls. Ipsilateral resistance index was increased (P = 0.0107) on day 180 of gestation compared with days 200 and 220 of gestation. Ipsilateral pulsatility index was decreased (P < 0.0001) on day 220 of gestation compared with days 140 and 180 of gestation. Contralateral blood flow was decreased (P = 0.0037) on day 140 of gestation compared with days 180, 200, and 220 of gestation. There were no differences in contralateral uterine artery blood flow, resistance index, or pulsatility index, or gestation length between treatment groups. Birth weights were decreased (P = 0.0102) among calves from seminal plasma treated cows compared with calves from control cows. In summary, seminal plasma uterine priming reduced offspring growth while increasing uterine artery resistance index, which indicates uterine vascular bed anomalies that persisted into the third trimester of pregnancy.