Featured Research

from universities, journals, and other organizations

Pregnancy in horses: Helping horses come to term

Date:
August 2, 2013
Source:
Veterinärmedizinische Universität Wien
Summary:
It is not only humans that sometimes experience difficulty having children. Horses too have a low birth rate, with many pregnancies failing within the first few weeks after conception. The reason is currently unknown but recent research suggests that a particular class of blood cells may be involved.

Mare with her new foal.
Credit: Copyright Vetmeduni Vienna/C.Aurich

It is not only humans that sometimes experience difficulty having children. Horses too have a low birth rate, with many pregnancies failing within the first few weeks after conception. The reason is currently unknown but recent research by the team of Christine Aurich at the University of Veterinary Medicine, Vienna (Vetmeduni) suggests that a particular class of blood cells may be involved.

The results have just been made available online in the journal Reproduction, Fertility and Development.

As any nervous first-time mother will confirm, the initial three months of pregnancy are the most risky time: many expectant women are reluctant to inform their friends or colleagues that they are pregnant until after this period is past. It is less well known that horses suffer from similar problems, with a considerable number of pregnancies failing to progress beyond the first five weeks. The explanation is still unclear but may relate to a problem with the mare's immune system, as the latest work in the group of Christine Aurich in the Vetmeduni's Centre for Artificial Insemination and Embryo Transfer strongly suggests.

The fertilized egg, or conceptus, obviously contains contributions from the stallion as well as the mare, which means it somehow has to avoid being recognized and attacked by the mare's immune system. Horse breeders talk about maternal tolerance of the conceptus and horses -- as other animals -- have a variety of mechanisms to enable fertilization and a successful pregnancy. Maternal tolerance probably depends on wide-ranging changes to the maternal immune response. But what makes some mares better than others at adapting their immune systems?

There are indications from work in humans and mice that a particular class of immune cell, the so-called regulatory T cells or Tregs (pronounced "tea regs"), might somehow be important in maternal tolerance. Aurich and her colleagues have now developed a highly sensitive assay to measure the proportion of Tregs in the blood of horses. They used their new technique to investigate over 100 mares that were presented for artificial insemination, correlating the results with the outcome of the resulting pregnancies.

Of course, not all of the animals conceived. The scientists could find no association between the level of Tregs in the mares' blood with the success of the insemination procedure. However, they did observe clearly lower numbers of Tregs in the blood of horses that suffered an early loss of pregnancy compared with those that either aborted much later (for whatever reason) or gave birth to live foals. The results suggest that high numbers of Tregs might somehow be required to suppress the mare's natural immune reaction against the conceptus. In other words, low levels of Treg cells in mares might cause pregnancy loss in the five weeks after fertilization.

The differences in the levels of Tregs between horses in the "successful pregnancy" and the "unsuccessful" groups were too small to be useful to predict whether an individual mare is likely to suffer early pregnancy failure. Nevertheless, the results may help breeders solve the problem. There is evidence from human medicine that oestradiol may enhance the function of Tregs during pregnancy and treatment with this hormone could possibly benefit mares prone to losing the conceptus. Another possible course would be to expose mares to the stallion's semen before implantation, which might increase the number of Tregs in the blood and the animal's tolerance to the conceptus, thereby helping avoid early pregnancy losses.

Aurich is optimistic: "A number of reasons have been proposed to account for early pregnancy failure in the horse but our work suggests that a low level of Tregs may actually be among the most important factors. It can only be a matter of time before we find out how to solve the problem."


Story Source:

The above story is based on materials provided by Veterinärmedizinische Universität Wien. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christine Aurich, Jurgen Weber, Christina Nagel, Maximiliane Merkl, Rony Jude, Sascha Wostmann, Dirk Ollech, Udo Baron, Sven Olek, Thomas Jansen. Low levels of naturally occurring regulatory T lymphocytes in blood of mares with early pregnancy loss. Reproduction, Fertility and Development, 2013; DOI: 10.1071/RD13012

Cite This Page:

Veterinärmedizinische Universität Wien. "Pregnancy in horses: Helping horses come to term." ScienceDaily. ScienceDaily, 2 August 2013. <www.sciencedaily.com/releases/2013/08/130802080235.htm>.
Veterinärmedizinische Universität Wien. (2013, August 2). Pregnancy in horses: Helping horses come to term. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2013/08/130802080235.htm
Veterinärmedizinische Universität Wien. "Pregnancy in horses: Helping horses come to term." ScienceDaily. www.sciencedaily.com/releases/2013/08/130802080235.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins