146 Specific Gravity as an Objective Assessment of Embryonic Viability to Improve Implantation Rates of Bovine Embryos

Assessment of embryo quality and viability has traditionally been based on morphological evaluation. However, morphological evaluation, though somewhat reliable, is subjective in nature and varies greatly depending upon the skill and experience of the evaluator. Although research has been conducted with the goal of identifying more accurate and objective methods of evaluation, the issue of repeatability and consistency in predicting the likelihood of a successful pregnancy remains. Previous research has proposed the ability to utilize specific gravity to predict developmental energy reserves based on embryonic weight, theoretically identifying those embryos with an increased chance of success following standard embryonic transfer. The objective of this study was to determine if specific gravity could accurately identify those embryos that were most likely to succeed in generating positive pregnancies. Bovine embryos (n = 20) were dropped through media in a specific gravity chamber. Utilizing an embryo tracking software program, researchers recorded the time elapsed as the embryos descended 1 cm through the media. Embryos were then transferred into recipient cattle, and pregnancy was detected via ultrasound approximately 40 days post transfer. Of the 20 embryos transferred, 12 resulted in positive pregnancies. Descent times of these positive pregnancies ranged from 25.96 to 90.27 seconds, with an average descent time of 59.72 seconds. An analysis of the relationship between descent time and pregnancy outcome showed no significant difference (P > 0.05). Although there was no significance in the findings of this study, additional trials will be performed to thoroughly evaluate the potential of this technology as an objective measurement of embryonic viability.

Adverse Impact of Heat Stress on Bovine Development: Causes and Strategies for Mitigation

Heat stress induces the richness and reproductive domesticated animal’s performance by settling the physiology conceptive steps, through hormonal irregularity, diminished oocyte quality and feeble semen quality, and diminished undeveloped organism advancement and endurance. It depends on principally milk production, nutrition, disease management, sexual activities, and heat stress tolerance capacity in livestock farming. The decreases infertility caused by elevated blood heat influences sex gland regulation, oestrus regulation, and gametocyte disturbance and also affects embryonic development. Heat stress reduces the degree of dominance of the seminal vesicles and this may be observed as reduced steroidogenic capability of its theca and granulose cells as fall in blood oestrogen concentrations. Plasma progestin levels are also diminished counting on whether or not the heat stress is acute and on the metabolic state of the animal. The endocrine changes the cyst activities and alters the ovulatory mechanism leading to a decrease in gametocyte and embryo quality. Summer infertility may be countered through oestrus behaviour can be mitigated by with the help of implementation of ovulation phase treatments to limited period of embryonic transfer and also advanced reproductive technologies involving hormonal treatments, systematic artificial insemination and which may enhance the possibility of establishing pregnancy in domestic animals.

88 Plasma anti-Müllerian hormone as a marker for ovarian follicular population and oocyte quality in alpacas

The limited success of embryonic transfer technique in alpacas is related to the high variability of superovulation protocols, the response to which depends on, among other factors, the number of antral follicles growing along a follicular wave. The concentration of anti-Müllerian hormone (AMH) is correlated with antral follicle count, making it a reliable biomarker for identifying the number of available follicles and allowing us to ensure the reproductive potential of females. Studies in different production animals exist, but, thus far, no published studies exist on the use of AMH as a biomarker in alpacas. Thus, its study is necessary in order to be able to choose the best donors for embryonic transfer, reducing response variability and unnecessary expenses in superovulation protocols. The objective of this study was to determine whether AMH is a reliable marker for the number of follicles and quality of oocytes in an induced follicular wave in alpacas. We used 52 female, nonpregnant Suri alpacas of reproductive age (3–7 years), with a body condition score between 2.5 and 3.5 (where 1 is extremely thin and 5 is obese), and with the presence of a preovulatory follicle (diameter ≥7mm) determined through transrectal ultrasound. Blood samples were collected from nonpregnant Suri alpacas 5 days post-induction of ovulation and divided into groups according to AMH concentration. AMH concentrations were then correlated with the number of follicles and percentage by sizes of follicles using the least significant difference test with adjusted means. To relate the quality of oocytes with the AMH concentration groups, a Chi-square test was used. The high-AMH group had a greater number of follicles than the low-AMH group (20.51±2.76 vs. 11.58±2.55; P=0.036). There were no significant differences between AMH groups and percentage of follicle sizes. However, the high-AMH group had a greater percentage of follicles 3- to 7-mm long (67.49%). Furthermore, the high-AMH group showed dependence on the quality of oocytes (P=0.02). These results indicate that the plasma concentration of AMH can be a reliable marker for follicle and oocyte quality in Suri alpacas. Future investigations are needed to ensure the optimal timing to collect blood samples, a kit individualized to the species, and improvement of the future donors for current superovulation protocols in alpacas.