Successful embryonic development is dependent on factors secreted by the reproductive tract. Dickkopf-1 (DKK1), an antagonist of the wingless-related mouse mammary tumor virus (WNT) signaling pathway, is one endometrial secretory protein potentially involved in maternal-embryo communication. The purpose of this study was to investigate the roles of DKK1 in embryo cell fate decisions and competence to establish pregnancy. Using in vitro-produced bovine embryos, we demonstrate that exposure of embryos to DKK1 during the period of morula to blastocyst transition (between d 5 and 8 of development) promotes the first 2 cell fate decisions leading to increased differentiation of cells toward the trophectoderm and hypoblast lineages compared with that for control embryos treated with vehicle. Moreover, treatment of embryos with DKK1 or colony-stimulating factor 2 (CSF2; an endometrial cytokine known to improve embryo development and pregnancy establishment) between d 5 and 7 of development improves embryo survival after transfer to recipients. Pregnancy success at d 32 of gestation was 27% for cows receiving control embryos treated with vehicle, 41% for cows receiving embryos treated with DKK1, and 39% for cows receiving embryos treated with CSF2. These novel findings represent the first evidence of a role for maternally derived WNT regulators during this period and could lead to improvements in assisted reproductive technologies.

Many classrooms in higher education still rely on a transformative approach to teaching where students attend lectures and earn course grades through examination. In the modern age, traditional lectures are argued by some as obsolete and do not address the learning needs of today’s students. An emerging pedagogical approach is the concept of the flipped classroom. The flipped classroom can simply be described as students viewing asynchronous video lectures on their own and then engaging in active learning during scheduled class times. In this study, we examined the flipped classroom teaching environment on student learning gains in an Introduction to Equine Science course. Students (n = 130) were asked to view 7.5 h of recorded lectures divided into 8 learning modules, take online quizzes to enforce lecture viewing, take 3 in-class exams, and prepare to participate in active learning during scheduled class times. Active learning approaches included individual activities, paired activities, informal small groups, and large group activities. When compared to students in the traditional lecture format in earlier years, students in the flipped format scored higher on all 3 exams (P < 0.05), with both formats taught by the same instructor. Analysis of ACT scores demonstrated no intellectual capacity differences between the student populations. To evaluate any gains in critical thinking, flipped format students were asked to take the Cornell Critical Thinking Exam (version X). Scores improved from the pretest (50.8 ± 0.57) to the posttest (54.4 ± 0.58; P < 0.01). In the flipped course, no correlations were found with student performance and interactions with online content. Students were asked in class to evaluate their experiences based on a 5-point Likert scale: 1 (strongly disagree) to 5 (strongly agree). The flipped classroom was ranked as an enjoyable learning experience with a mean of 4.4 ± 0.10, while students responded positively to other pointed questions. In formal course evaluations, flipped format students ranked the following higher (P < 0.05): instructor availability to assist students; encouragement of independent, creative, and critical thinking; and amount learned. Overall, the flipped classroom proved to be a positive learning experience for students. As the classroom continues to modernize, pedagogical approaches such as the flipped classroom should be considered for many lecture-style courses taught in the animal sciences.

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The objective of this experiment was to determine whether uterine or ovarian vascular dynamics could be used to identify cows at risk for pregnancy loss. Our hypothesis was that cows that subsequently lose their pregnancy will have decreased corpus luteal (CL) perfusion, or an increased resistance index (RI; reduced blood flow), or both, at d 34 of pregnancy. Day 34 was chosen because it is a common time for dairy cattle to be checked for pregnancy. This experiment was performed in 2 replicates from November 2011 to April 2012 (n = 69) and from November 2012 to April 2013 (n = 53). Cows were bred via timed artificial insemination using Ovsynch-56 and checked for pregnancy on d 32 after artificial insemination. At d 34, cows confirmed pregnant were examined via transrectal Doppler ultrasonography. Blood samples collected via coccygeal vein were used to measure circulating plasma progesterone concentrations. Diameter of the corpus luteum and crown-rump length were measured. Color power Doppler ultrasonography was used to determine vascular perfusion to the CL, and RI was measured for the uterine arteries just after branching from the umbilical artery. Records were later examined to identify pregnancy status of cows after reconfirmation. Abortion rate did not differ between replicates (11.6% in replicate 1, 9.4% in replicate 2). Mean crown-rump length of embryos that were carried to term was greater on d 34 than that in cows that aborted (14.23 ± 0.27 vs. 13.21 ± 0.53 mm). Circulating progesterone concentration at d 34 was greater for cows that carried pregnancies to term than for those that aborted (9.1 ± 0.7 vs. 7.5 ± 1.0 ng/mL). The final logistic regression model consisted of crown-rump length, progesterone concentration, and RI of the uterine artery contralateral to pregnancy. Decreased crown-rump length and progesterone concentration tended to be associated with increased odds ratio for pregnancy loss, whereas CL perfusion and uterine blood flow were not associated with increased odds ratio of pregnancy loss. In conclusion, examining CL perfusion and RI of the uterine arteries on d 34 of pregnancy does not offer a method to identify lactating Dairy cattle at risk for pregnancy loss after d 34.

The advent of embryo transfer has allowed horses to continue to train and compete during the breeding season. However, the associated stress of exercise may be detrimental to reproduction. The objectives of this study were to evaluate differing exercise protocols on reproductive blood flow and embryonic outcomes in mares. Light-horse mares were randomized into control (n = 4), partial-exercised (n = 6), and full-exercised (n = 6) groups. Partial-exercised mares were moderately exercised 30 min daily during the periovulatory period and rested after ovulation for 7 d. Full-exercised mares were exercised for 30 min daily throughout the reproductive cycle. Mares were artificially inseminated during estrus and subjected to uterine flush for embryo recovery on d 7 post ovulation. Blood flow through both ovarian arteries and vascular perfusion of the wall of the preovulatory follicle were examined by color Doppler ultrasonography. Results indicated exercise induced greater serum cortisol concentrations (P < 0.05). Embryo recovery rates were reduced in exercised (20/46, 43%) compared with control (14/21, 67%) mares (P < 0.10). When examined separately, embryo recovery rates for partial-exercised (11/25, 44%) and full-exercised (9/21, 43%) mares were not significantly different. Additionally, fewer quality Grade 1 embryos were recovered from partial-exercised mares compared with both control and full-exercised mares (P < 0.05). Blood flow through both ovarian arteries was greater in both exercised groups in the days leading up to ovulation (P < 0.05). However, vascular perfusion of the wall of the preovulatory follicle on the day before ovulation was less in both partial-exercised (45.9 ± 3.0%) and full-exercised (44.8 ± 3.4%) mares vs. control (54.9 ± 3.6%; P < 0.05). In exercised mares, vascular perfusion of the follicle wall was greater when an embryo was recovered (P < 0.01). No differences were found in follicle ovulatory diameter among exercised and non-exercised mares. When groups were combined, follicle diameter was greater when an embryo was recovered (44.9 ± 1.0 mm) compared with an unsuccessful embryo recovery attempt (42.8 ± 0.7 mm; P < 0.05). In conclusion, these data demonstrated that exercise increased ovarian arterial blood flow leading up to ovulation and decreased vascular perfusion of the wall of the preovulatory follicle. Mares given rest the day after ovulation up until an embryo collection attempt did not improve embryo recovery rates.

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