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OVC Researchers Explore New Ways to Assess Bovine Embryos

Dr. Pavneesh Madan, Ontario Veterinary College, University of Guelph Researchers at the University of Guelph’s Ontario Veterinary College (OVC) are exploring a new method to assess bovine embryos in order to enhance reproduction in elite dairy cows and improve fertility rates in cattle.

Dr. Pavneesh Madan, an internationally renowned expert in bovine reproductive biology, is developing markers of embryonic health to improve current methods of embryo selection in cattle and taking a page from human medicine to further advance his work.

A professor in OVC’s Department of Biomedical Sciences, Madan will use a Natural Sciences and Engineering Research Council (NSERC) Research and Tools Instruments (RTI) award to purchase a benchtop embryo incubator with live imaging abilities and assessment software.

He will use this benchtop embryo imaging incubator to determine viability using morpho-kinetics, a new method for bovine embryo selection.

A bovine blastocyst stained with fluorescent dyes and imaged using confocal microscope.This approach is well-studied and gaining popularity in human medicine, but Madan and his colleagues in the Reproductive Health and Biology Laboratories at OVC will undertake pioneering work on embryo selection and quality assessment by using this technique, which is in its infancy for bovines.

Traditionally, embryo viability was assessed by veterinarians or embryologists using morphology, a technique examining the embryo’s form and structure. However, this method is poorly correlated to embryonic success and is incapable of detecting poor quality embryos, which in turn, becomes the primary cause of early embryonic failure and related productivity losses in cattle.

Following fertilization, early embryonic development is characterized by cleavage events, where cells divide in a regular pattern and within a predictable amount of time. The morpho-kinetics method can evaluate these cell divisions in real time, recognizing a successful embryo as one that cleaves at predictable times and in a specified manner in addition to morphological analysis.

The benchtop incubator takes microscopic photos of embryos every few seconds during incubation, using software to automatically detect major embryonic events, including each cell division and blastocyst formation. A blastocyst is a ball of rapidly dividing cells formed from an embryo, which will eventually develop into fetal tissue and the placenta.

With in-depth knowledge of major embryonic events, researchers can assess how long the embryo spent in each stage of development, observations that can then be used to determine which embryos would be the most successful when transferred into a cow.

This equipment provides live updates and reviewable data throughout development, without exposing embryos to room light or alterations in culture temperature.

In the Canadian dairy industry, reproductive technologies such as artificial insemination, embryo transfer and in vitro fertilization (IVF) are considered one of the most important ways to assist animal breeding and husbandry, notes Madan. “However, one of the biggest questions regarding bovine embryo viability is which embryo has the highest possibility of leading to pregnancy?”

“The cattle industry is extremely important in Canada, generating over $40 billion annually, through direct and indirect revenue,” adds Madan. “Canada remains one of the most significant exporters of livestock in the world. In order to maintain this level of production, we must optimize dairy cattle reproduction by developing reliable markers to predict bovine embryonic success and viability.”

Madan emphasizes that “As fertility rates decline in cattle around the world, this technology is needed now more than ever. With the need of developing sustainable production systems, it is important to establish methods that lower reproductive and production losses and help farmers to produce more with less of a carbon footprint.”