Search

Seminal plasma primes the uterus for pregnancy through the recruitment of cells aiding in microbial clearance, tissue remodeling and angiogenesis, and embryo implantation and growth. Less is known about the effects of seminal plasma uterine priming in practices devoid of seminal plasma, specifically evaluating offspring growth in embryo-recipient beef cows. In the present study, we sought to determine the effects of seminal plasma uterine priming on postnatal body weights, carcass ultrasound measures, and indices of body composition. To realize these objectives, embryo-recipient cows randomly received 0.5 mL of pooled seminal plasma or no treatment (control) at estrus and underwent embryo transfer seven days later. Following parturition, offspring pre-weaning body weights were collected at 30, 90, and 180 days of age. Indices of body composition, carcass ultrasounds and bioelectrical impedance analysis (BIA), were collected pre-weaning at an average 209 days of age. Weaning weights and hip heights were collected at an average of 212 days of age. Ultrasound, BIA, and weaning weight data were analyzed using the MIXED procedure of SAS for fixed effects of treatment. Pre-weaning body weights were analyzed similarly with repeated measures for treatment, day, and their interaction. Covariates of sire, dam, sex, and age were included in all models if P = 0.10. Correlations between carcass ultrasounds and BIA parameters of fat-free mass and fat-free soft tissue were analyzed using the CORR procedure of SAS. Significance is declared at P = 0.05 and data were presented as means ± standard error. A treatment by day interaction was not observed for pre-weaning body weight. However, a main effect of treatment was observed for pre-weaning body weights, which was decreased (P = 0.0130) in seminal plasma calves compared with controls. Weaning weights and hip height were not different between treatments. There was not an effect of treatment on carcass ultrasound measures, including ribeye area, ribeye area adjusted by body weight, rib fat, intramuscular fat, or rump fat. Similarly, BIA measures of fat-free mass and fat-free soft tissue were not different between treatments. Ribeye area and rib fat ultrasound were moderately correlated (P < 0.05) with BIA measures of fat-free mass and fat-free soft tissue. Interestingly, previously reported data from this project show offspring from seminal plasma treated cows had decreased embryo size at days 35, 40, and 45 of gestation, and decreased birth weights. It appears seminal plasma uterine priming prior to embryo transfer negatively impacts offspring growth pre-weaning, however, by weaning this difference is diminished. It is less clear why pre-weaning weights differ due to similar body composition among treatment and control calves; however, these measures may have been collected after the period of compensatory gain occurred. [ABSTRACT FROM AUTHOR]

The vaginal microbiota (VM) is the first contact of the neonate with microorganisms, which can attribute to neonatal health outcomes. The effects of an altered VM at parturition on neonatal microbial inoculation and passive transfer success has not been evaluated. Betadine lavages (BL) are commonly used to mitigate bacterial infections within the reproductive tract by ablating the VM. Ablation of the VM prior to parturition decreases microbial competition during neonatal microbial colonization, increasing the likelihood for pathogen inoculation. Thus, this study aimed to determine if an altered VM impacts neonatal and dam microbial inoculating bacterial communities in beef cow-calf pairs. Cows (n = 12) were randomly assigned to either control (CON) or BL (BLG) treatment groups two weeks prior to calving. Treatment BL was infused into the anterior vagina weekly until calving. Samples (dam-vaginal swab, dam-udder swab, damhaircoat swab, and calf-nasal swab) were collected within 24 hours of parturition and stored at -80°C. The vaginal bacterial community composition was determined through sequencing of the V3-V4 region of the 16S rRNA gene using the Illumina Miseq platform. Alpha diversity was compared via two-way ANOVA; beta diversity was compared via PERMANOVA. Taxonomic differences were evaluated using the LEfSe platform. Microbiota data were analyzed using the R software package. Serial BL prior to parturition did not alter the alpha diversity of the dam-vaginal (P = 0.42), dam-udder (P = 0.53), or dam-haircoat (P = 0.21) microbiota but did alter the calf-nasal microbiota (P = 0.03). Moreover, the beta diversity did not differ within the dam-vaginal (P = 0.66) or dam-udder (P = 0.56) between BLG vs. CON, but there was a trend within both the calf-nasal (P = 0.08) and dam-haircoat (P = 0.09) for BLG pairs to have increased variation compared with CON. Within the calf-nasal microbiota, BLG had increased relative abundance of Actinobacteria and a decreased relative abundance of Proteobacteria compared with CON. Interestingly, previously reported IgG data from this study showed there was no difference in passive transfer status between CON and BLG calves, represented by no significant differences in calf serum (P = 0.88). However, BLG dam colostrum had increased IgG concentrations compared with CON dams (P = 0.04). Together, these results are indicative of physiological insults (BL) prior to parturition leading to an increased immune response in BLG dams which altered colostrum IgG. Thus, neonatal colostrum consumption could drive immune responses against inoculating bacteria resulting in differing nasal microbial communities between BLG and CON calves. Overall, this research contributes to our understanding of the vaginal microbiota and its importance in neonatal health outcomes and highlights the need for further research in this area to better inform management practices for optimal calf health and productivity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The vaginal microbiota (VM) is one of the initial contacts of the neonate with microorganisms and can attribute to neonatal health outcomes. The impacts of an altered VM on post-partum dam and neonatal immune responses has not been evaluated. Betadine lavages (BL) have been used to mitigate bacterial infections within the reproductive tract by ablating the VM. Thus, this study aimed to determine if an altered VM impacts passive transfer and immune responses in post-partum dams & calves. Commercial beef cows (n = 22) were randomly assigned to either the control group (CON) or BL treatment group (BTL) two weeks before calving. Treatment BL bags were infused into the anterior vagina and cows received 1 of 3 treatments depending on calving date. Blood samples were gathered from the dam and calf at 0, 5, 30 and 60 days post-partum. Processed blood serum and dam colostrum samples were stored at -80°C. Calf serum (0 d) and dam colostrum were analyzed for immunoglobulin (IgG) concentration via a commercial ELISA. A D2Dx testing kit was used to determine immune status in both dam and calves at 1,5, 30, and 60 days by using gold nanoparticles as a pathogen substitute to identify immune system factors within serum samples. The test produces a numerical score that can be correlated to immune response strength. All IgG data were analyzed using R software. All D2Dx data were analyzed using repeated measures of ANOVA (SAS software version 9.4). There was no difference in passive transfer status between CON and BTL calves, represented by no significant differences in calf serum (P = 0.62) or dam colostrum (P = 0.32) concentrations of IgG. In dams, there was a main effect of day with immune responses decreasing at 60 days postpartum compared with 0d (P < 0.001),5d (P < 0.001), and 30d (P < 0.001). In calves, there was a main effect of day where immune responses were increased on5d compared with 30d (P = 0.046) but decreased on d 5 compared with d 60 (P = 0.005). Moreover, there was a decreased immune response in calves at d 0 (P < 0.001) and d 30 (P < 0.001) compared with d 60. In calves, there was a tendency (P = 0.08) for BTL calves to have a decreased immune response compared with CON. Interestingly, immune status fluctuated in both dams and calves from calving to 60 d post-partum. While full elucidation of causes behind these fluctuations is limited, more research evaluating their implications is warranted. [ABSTRACT FROM AUTHOR]

Poorly functioning placenta restricts oxygen and nutrient supply to the fetus resulting in fetal nutrient deficiency and intrauterine growth restriction. Intrauterine growth restriction dramatically increases neonatal mortality and those who survive are more prone to experience metabolic diseases such as cardiovascular diseases, hypertension, and type 2 diabetes in later life. Therefore, the placenta plays a critical role in the developmental origins of health and diseases. Currently, there is a vast effort evaluating the effects of compromised pregnancies such as maternal undernutrition, overnutrition, and heat stress on fetal development; however fewer studies have evaluated potential therapeutics to enhance placental efficiency and offspring performance. Melatonin, a hormone that modulates circadian rhythms, has shown to increase umbilical and uterine blood flow in pregnant dams. Moreover, a recent study observed that melatonin therapeutic effects during compromised pregnancies are seasonally dependent. Dietary melatonin supplementation to pregnant beef cattle increased uterine blood flow, rescued fetal weights, increased angiogenic factors in the placenta, and reduced vaginal temperatures in the summer, but not in the fall. The same study found that maternal nutrient restriction was more detrimental during the fall reducing uterine blood flow. Additionally, it was observed that dams that are nutrient restricted during the summer exerted a compensatory mechanism at the placentome level where they exhibited greater placentome vascularity and increased placental capillary size and angiogenic factors. Lastly, bovine placental circadian rhythms have been identified and interestingly, temporal increases in placental vascularity occur concomitantly with greater melatonin receptor 1A transcript abundance. In conclusion, these findings provide a better understanding of placental insufficiency and impaired fetal growth during maternal nutrient restriction, while temporal alterations in the placenta could lead to the development of proper guidelines for administration of placental blood flow therapeutics such as melatonin. Future studies should evaluate melatonin impacts on offspring organ development and potential for mitigating heat stress in livestock. [ABSTRACT FROM AUTHOR]

Flunixin meglumine (FM) is a COX enzyme inhibitor and prostaglandin E2 (PGE) builds the corpus luteum (CL). However, the use of FM in conjunction with PGE has not been studied. The objective of this study was to determine effects of intravenous administration of FM and intravaginal release of PGE on characteristics of the CL and concentrations of PGE and progesterone in blood. Beef cows (n = 24, divided between two replicants over time) were synchronized using the Select Synch + CIDR protocol (expected estrus = d 0). Cows were randomly assigned to one of four treatment groups in a factorial arrangement, with 6 cows in each: Control, FM, PGE, or FM+PGE. Treatments were administered from d 13 to 19 (FM 2.2 mg/kg iv every 12 hr; PGE released in osmotic pump at 0.1 mL/d). Every other day from d 0 to 26, transrectal ultrasonography with color Doppler was used to measure size and blood perfusion of CL; images were later analyzed with ImageJ. Blood samples were collected via jugular venipuncture every other day from d 13 to 26 and later analyzed for concentrations of progesterone (P4; RIA) and PGE (ELISA). Data were analyzed using the mixed procedure of SAS 9.4 with day as a repeated measure; significance was declared when P = 0.05. There were no interactions between FM and PGE, thus main effects of treatments were evaluated. There were no differences (P = 0.164) in size, vessel density, or blood perfusion of CL between treatment groups. There were no differences (P = 0.141) in concentrations of PGE or P4 between treatment groups. However, concentrations of P4 and PGE and density of blood vessels decreased by day (P = 0.05). In conclusion, treatment with FM or PGE did not influence CL characteristics nor concentrations of P4 or PGE in circulation. [ABSTRACT FROM AUTHOR]

Objectives were to evaluate characteristics of corpora lutea (CL) and concentrations of progesterone (P4) in beef recipient cows stimulated with follicle stimulating hormone (FSH) prior to embryo transfer. Forty suckled beef cows received the CO-Synch+CIDR protocol and were randomly assigned to one of two treatments: 1) exogenous FSH (FSH; 1.0 mL im 2x/d on d -4 and -3, 0.5 mL 2x/d on d -2 and -1) or 2) no treatment (CON). Estrous behavior was observed for 48 hr; d 0 = expected estrus. Frozen-thawed embryos were transferred (d 7) into the 36 females observed in estrus. Transrectal ultrasonography was used to measure number of CL and size of the largest CL, blood perfusion of luteal tissue, and pregnancy (d 35). Ultrasonography and blood samples were collected on d 7, 14, 21, and 28. Data were analyzed using repeated measures of ANOVA with significance declared at P = 0.05. LSMeans and SEM are presented. On d 21 and 28, cows in the FSH group had decreased (P < 0.05) size of the largest CL compared with CON (d 21 = 1.81±0.309 vs 3.20±0.293 cm2 and d 28 = 1.88±0.332 vs 2.84±0.322 cm2). Area of blood perfusion was similar between FSH and CON groups (P > 0.05), but on d 21 and 28 it was greater in pregnant cows compared with non-pregnant cows (9.78±2.109 vs 22.43±1.995 and 4.42±2.607 vs 26.38±2.533, P < 0.0001). On d 7, 14, and 21, FSH group had greater concentrations of P4 and number of CL (P = 0.05). Additionally, on d 28, concentrations of P4 and number of CL were greater in FSH-pregnant cows compared to all others (P = 0.05). In conclusion, FSH decreased size of the largest CL but increased number of CL and P4 on most days; it did not affect blood perfusion. [ABSTRACT FROM AUTHOR]

The role of the reproductive tract microbiota is an emerging field receiving considerable attention in human research, whereby the vaginal microbiota has been characterized in relation to fertility, conception, pregnancy, and parturition. However, the acidic, Lactobaccillus dominated vaginal microbiota in humans contrasts the neutral, dynamic microbial environment characterized in cattle. Over the past few years, many postpartum studies in dairy cattle described a mechanism recently proposed in humans, the ascension of the vaginal microbiota into the uterine body at the onset of labor. Although bovine fetal sterility prior to parturition is under debate, the vaginal microbiota is an early contact for the neonate with microorganisms and inoculates the uterus during parturition. Thus, any changes occurring in the vaginal microbiota could have implications in dam and calf health; this, combined with ease of access, led to the current research focusing on the bovine vaginal microbiota. Characterization studies during the estrous cycle, gestation, and postpartum period have been performed, concluding the bovine vaginal microbiota is dynamic. However, due to the low abundance in the vaginal microbiota, the seemingly small taxonomic changes reported in these studies could be of great importance. Secondly, researchers have begun to evaluate the effect of exogenous and endogenous hormone concentrations on the vaginal microbiota. Little to no differences have been found except with exogenous melatonin supplementation. In pregnant heifers, exogenous melatonin altered the beta diversity of the vaginal tract by increasing aerobic bacteria present. Moreover, a study evaluating the effects of nutrient restriction on the vaginal microbiota found no taxonomic or structure differences. These findings have allowed researchers to target paucities, improve methodology, and realize the importance of the reproductive tract microbiota. In short, based on these studies, future research examining the role of the reproductive tract microbiota could uncover mechanisms vital to increasing reproductive performance. [ABSTRACT FROM AUTHOR]

The objectives were to examine melatonin mediated changes in temporal uterine blood flow (UBF) and vaginal temperatures (VT) in 54 Brangus heifers (Fall, n = 29; Summer, n = 25) during compromised pregnancy. At d160 of gestation, heifers were assigned to 1 of 4 groups consisting of adequately fed (ADQ-CON; 100% NRC; n=13), global nutrient restricted (RESCON; 60% NRC; n = 13), and ADQ or RES supplemented with 20 mg of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). In the morning (0500h) and afternoon (1300h) of d220 of gestation, temperature dataloggers (Onset Computer Corporation) attached to progesterone-free CIDRs were used to record VT, while UBF was determined via Doppler ultrasonography. Data were analyzed using repeated measures of ANOVA (SAS). Significant differences were found in UBF and VT between Fall and Summer groups (P< 0.05), therefore seasons were individually analyzed. In Fall, a nutrition by treatment interaction was significant, where the RES-CON heifers exhibited reduced total UBF compared to ADQ-CON (5.67±0.68 vs. 7.97±0.54 L/min; P = 0.012). In Summer, there was not a main effect of nutrition (P = 0.390); nevertheless, the MEL heifers exhibited increased total UBF compared to the CON counterparts (8.16±0.73 vs. 6.00±0.70 L/min; P = 0.048). Moreover, there was a nutrition by treatment by time interaction in VT for Fall and Summer heifers (P < 0.0001). In Fall, all groups had decreased VT in the morning compared to the afternoon (P < 0.0001). Whereas, in Summer, VT increased for ADQ-CON, RES-CON, and ADQMEL from morning to afternoon (P < 0.0001), while the RES-MEL remained constant throughout the day (P = 0.649). Furthermore, during the afternoon RES-MEL heifers exhibited decreased VT compared to ADQ-CON (38.91±0.09 vs. 39.26±0.09°C, respectively; P=0.039). In summary, nutrient restriction and melatonin supplementation altered UBF in a season dependent manner. Additionally, with the VT differences observed in Summer, future studies should evaluate the potential of melatonin supplementation for mitigating heat stress in farm animals. [ABSTRACT FROM AUTHOR]