Early Embryonic Death

early embryonic death

LLamas have it tough when it comes to pregnancy.  Not only do they have to carry those crias for 11 months, they also have one of the highest rates of pregnancy failure.  Some estimates are that 57% of all pregnancies are lost, usually within the first 45 days of pregnancy.  While fertilization rates are usually high (>85%) many female llamas become receptive to breeding again within a month, indicating early embryonic death.  Repeat breeders and older females are more likely to experience early loss of pregnancy.

What could be causing early embryonic death?

Although all the reasons aren’t known, here are some of the more common ones (in no particular order):

Corpus luteum dysfunction

Similar to all mammalian females, pregnant llamas require ovarian progesterone to maintain pregnancy.  While many mammalians only require the hormone early in pregnancy, llamas require it throughout the pregnancy.

The corpus luteum (CL) is a hormone-secreting structure that develops transiently in ovaries and releases high amounts of hormones during pregnancy.  It is this release of hormones that signals pregnancy to the body and prevents the female from mating again. If the CL fails, and progesterone levels drop, then the embryo will be aborted.

CL dysfunction is often suspected if the female aborts between days 25-60 of pregnancy.  CL insufficiency is most often seen in obese animals, lactating females or those with thyroid problems. You can administer hormones to females suspected of having CL insufficiency to help maintain the pregnancy.

Genetic factors

Genetic factors are also believed to contribute to early embryonic death.  Females can be born with physical defects of the reproductive structures that prevent implantation or maintenance of pregnancy.  These defects won’t be noticed until a female fails to maintain a pregnancy.  Physical defects are often suspected in females that have never been pregnant and can be diagnosed by physical exam. Alternatively, the ova itself can have a genetic defect that prevents successful implantation or adequate growth of the fetus. Both females and males can carry genetic abnormalities that affect the fetus and cause early abortion.

You can try and prevent genetic factors from contributing to early embryonic death by carefully examining the breeding habits and pregnancy outcomes in the family tree of the llamas that you intend to breed.

Twinning

Llamas usually cannot support more than one fetus. Therefore, when a female becomes pregnant with twins, they are often aborted.

Environmental factors

While genetic contributions to early embryonic death are largely out of your control, you can control environmental factors that contribute to pregnancy loss.  Heat stress, poor nutrition, infections, and environmental toxins (e.g. toxic plants) are common causes of embryonic death.  Llamas are particularly intolerant of heat.  They should be sheared regularly and have unlimited access to shade and water.  A lack of vitamins A, E and selenium have been linked to pregnancy, while many infectious agents can cause abortion.  Chlamydia, Toxoplasma, Leptospira and Brucella can all cause spontaneous abortions.

Proper management of breeders and maintenance of breeding facilities should limit the contribution of environmental factors to early embryonic death.

I have never bred llamas and reading about the problem of early embryonic death doesn’t make me want to jump right in and do it.  I might leave that to the experts.

Blogging my way from A to Z as part of the 2016 April A to Z Challenge!  My theme for this year:  Llama mama.  E is for Early Embryonic Death.

Photo courtesy of Thomas Widmann.


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