Older mares have older eggs, which can be a problem with reproduction. In a previous video, reproductive specialist Karen Wolfsdorf, DVM, DACT (Diplomate of the American College of Theriogenologists) talked about Breeding Maiden Senior Mares. In this video, she addresses the issue of older eggs in senior mares. Wolfsdorf is a partner in Hagyard Equine Medical Institute in Lexington, Kentucky.

(Editor’s note: The content of this video is the expert’s approach to the topic. Please consult with your practitioner if you have questions.)

Issues for Older Mares

Wolfsdorf reminds owners who want to breed older mares—whether they previously had foals or not—that there are issues they face.

She said a mare’s vulvar conformation change as she ages, and her uterus becomes’ baggy and saggy.’

“Also, the quality of their eggs, or oocytes, changes,” she said. “As mares get older, those eggs become older, too.”

She said breeders need to recognize that because pregnancy rates will be affected by those older eggs. The same is true for embryo rates if owners are using embryo transfer.

How to Help

Wolfsdorf said there are some things that owners and managers can do to help the quality of those oocytes. Part of that is helping the environment in which they live in the ovary.

She said that help can come from nutritional supplements. “That’s something to talk to your veterinarian about to try and help those eggs become more viable and better at producing embryos,” she said.

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