A friend has a 8 year old stallion who is being used in a transported semen program. The semen looks great on collection, motility is usually 55-60% at 24 hours, 45%+ at 48 hours. Looks very good. However, many mares are not getting in foal.
Would there be a reason why the motility would look good (very progressively motile) and the fertility not be good? Extender is ARS CST. Any thoughts on improving fertility?
corry_dvm (208.180.96.165)
Posted on Tuesday, June 04, 2002 - 07:13 pm:
Is the semen being shipped cooled or are they inseminating on the farm? What about the morphology (shape and normal appearance) of the sperm? How many mares are we talking, ages, fertility history, etc.? It could be a problem on the mares' end, too.
Stallion is breeding on farm with a very high conception rate and off-farm via transported cooled semen with a not so good conception rate. Semen looks great. Sperm cells look normal and motility is great (progressive motility). Some mares are getting in foal with cooled semen but more are not (say 1 out of 4) breeding around 40 mares with shipped semen.
Some cases mares could be problem but don't think so in all cases. Quite often timing is right on with young mares.
Jos (142.177.11.50)
Posted on Tuesday, June 04, 2002 - 10:13 pm:
Although motility os usually linked to fertility, it may not always be so.... it's one of nature's little jokes.
I would start by running a cooled semen evaluation with different extenders and antibiotics to see if there is a combination that works better. Although you indicate 45%+ at 48 hours, what is the degree of vigour?
Sometimes sperm undergo premature capacitation during transport, which can result in a sperm that may be motile, but infertile once it reaches the uterus. This is why proud claims that sperm have motility at 96+ hours mean nothing unless pregnancies have been achieved in that time frame!!
Start by running test cool evaluations and then take it from there. If you would care to contact me personally, I will be happy to attempt to assist. To do so please use our contact page by "clicking" here.
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