Costermans graduates Cum Laude

Published on
October 30, 2020

On Wednesday October 28 Natasja Costermans successfully defended her PhD thesis entitled ‘Physiological and Molecular Aspects of Ovarian Follicular Development and Competence in Sows’.

We are extremely proud that Natasja graduated Cum Laude. Natasja’s project was performed at the Human and Animal Physiology and the Adaptation Physiology chair group at WUR.

About the research

The project of Natasja focused on the problems that arise due to the recent breeding for large litters in sows, which results in higher piglet mortality. This higher piglet mortality is due to a combination of increased variation in litter birth weight and a higher number of piglets with a low birth weight.

Lower piglet birth weights and lower litter birth weight uniformity may be caused by variation in ovarian follicular development during the sow’s previous lactation. Breeding for large litters has resulted in high ovulation rates with the risk that follicles that normally would have degenerated are now ‘rescued’ and ovulated. The hypothesis Natasja testes in her PhD project was that these ‘rescued’ follicles are of less quality, resulting in a large pre-ovulatory follicle pool of variable quality. Furthermore, breeding for large litters increases the chance that sows enter a substantial negative energy balance (NEB) during lactation because they need to produce a higher than normal amount of milk to feed the large number of piglets. This NEB can negatively influence the development of follicles that will give rise to the next generation of piglets.

Natasja performed two large animal experiments, one on a pig farm and one at Carus. Next to collecting ovaries, she also collected blood samples, muscle and adipose tissue biopsies and milk samples to get the picture as complete as possible.


The thesis of Natasja contains six published articles in high quality journals. She even got a pig paper published in the prestigious journal Molecular Human Reproduction. Next to these six articles, Natasja is alo co-author on two additional high impact publication of fellow PhD students.

At the end of her PhD project she was granted a WIAS scholarship to write a research project proposal. Her NWO-Rubicon project proposal was granted which got her a post-doc position at the University of California San Francisco (UCSF) in the lab of professor Mario Conti to work on oocyte aging in mice.