73 Engaging youth through bovine reproductive practices

Two programs have been established at Virginia Tech with the purpose of engaging youth and showcasing agriculture. The Governor’s School for Agriculture (GSA) program began in 2001, and has over 1,850 graduates. High school juniors and seniors from different areas of the Commonwealth’s schools spend time on campus exploring the life sciences. The Virginia 4-H State Congress (4HC) is the premier, statewide annual 4-H event for outstanding teens, providing educational experiences to Virginia teens and helping them develop life skills and leadership abilities. Our extension group has focused on exposing teens enrolled in the GSA and 4HC to beef production, particularly bovine reproduction and reproductive biotechnologies. The 4-hr workshop, titled “Do it yourself cows”, consists of a mixture of in-class presentations and hands-on laboratories relating to bovine reproductive anatomy and physiology and reproductive biotechnologies. The wet-laboratory consists of bovine female reproductive tracts anatomy dissection and artificial insemination and rectal palpation simulation with a mannequin, as well as demonstrations of equipment used in the field including, nitrogen tank for semen storage, ultrasound and microscope visualization of bovine embryos. The GSA “Bovine Reproduction” course is 4 days long and allows for in-depth discussion of factors influencing fertility and case discussions on beef reproductive management. The hands-on portion of this course is similar to the 4HC workshop, however students are able to perform rectal palpation and ultrasonography in cattle. So far, 40 students from the GSA and 80 students from the 4HC (2 GSA, and 4 4HC programs) have graduated in the course. At the completion of both programs, a survey was performed and 100% of the students considered the program positive and gained knowledge and interest in bovine reproduction. Furthermore, 20% of students from the GSA program developed a desire to pursue a career in livestock production, and 92% of 4HC students claimed to have learned information they can apply in their communities. Our data indicate that we were successful in engaging youth in animal agriculture, specifically beef production.

Vascular Endothelial Growth Factor A and VEGFR-1 Change during Preimplantation in Heifers

Vascular endothelial growth factor A (VEGFA) plays a critical angiogenic role in the endometrium of placentalia during preimplantation. The role of VEGFA and its receptors is not fully characterised in bovine reproduction. We analysed the mRNA expression of VEGFA isoforms 121, 165 and 189, and VEGF receptors 1 and 2 in three experimental settings (A, B and C). We compared intercaruncular endometrium of cyclic to pregnant heifers at Days 12, 15 and 18 post insemination (Day 0), and between Day 15 and Day 18 conceptuses (A). We further compared caruncular versus intercaruncular endometrium at Day 15 (B), and endometrium of heifers carrying embryos originating from somatic cell nuclear transfer (SCNT) versus in vitro fertilisation (IVF) at Day 18 (C). Endometrial VEGFA protein was localised and quantified. Pregnant heifers displayed lower intercaruncular endometrial mRNA expression of VEGFA-121 (p = 0.045) and VEGFA-189 (p = 0.009) as well as lower VEGFA protein abundance (p < 0.001) at Day 15. The VEGFA protein was localised in intercaruncular luminal, glandular epithelium and in tunica muscularis of blood vessels. At Day 15, caruncular endometrium displayed higher VEGFA mRNA expression than intercaruncular endometrium (p < 0.05). Intercaruncular endometrial VEGFA protein at Day 18 was higher in abundance in SCNT than in IVF (p = 0.038). Therefore, during preimplantation in cattle, there may be a need for timely physiological reduction in intercaruncular endometrial VEGFA expression in favour of the caruncular area to facilitate a gradient towards the implantation sites. A higher expression of VEGFA in SCNT may predispose for later placentation abnormalities frequently observed following SCNT.

The vaginal and fecal microbiomes are related to pregnancy status in beef heifers

Background The greatest impact on profitability of a commercial beef operation is reproduction. However, in beef heifers, little is known about the vaginal and fecal microbiota with respect to their relationship with fertility. To this end, we followed heifers through gestation to examine the dynamics of vaginal and fecal microbial composition throughout pregnancy. Results Heifers were exposed to an estrus synchronization protocol, observed over a 12-day period, artificially inseminated 12 h to 18 h after observed estrus, and subsequently exposed to bulls for a 50-day breeding season. Vaginal samples were taken at pre-breeding (n = 72), during the first (n = 72), and second trimester (n = 72) for all individuals, and third trimester for individuals with confirmed pregnancies (n = 56). Fecal samples were taken at pre-breeding (n = 32) and during the first trimester (n = 32), including bred and open individuals. Next generation sequencing of the V4 region of the16S rRNA gene via the Illumina MiSeq platform was applied to all samples. Shannon indices and the number of observed bacterial features were the same in fecal samples. However, significant differences in vaginal microbiome diversity between gestation stages were observed. No differences in beta-diversity were detected in vaginal or fecal samples regarding pregnancy status, but such differences were seen with fecal microbiome over time. Random Forest was developed to identify predictors of pregnancy status in vaginal (e.g., Histophilus, Clostridiaceae, Campylobacter) and fecal (e.g., Bacteroidales, Dorea) samples. Conclusions Our study shows that bovine vaginal and fecal microbiome could be used as biomarkers of bovine reproduction. Further experiments are needed to validate these biomarkers and to examine their roles in a female’s ability to establish pregnancy.