# Factors determining lamb sex?



## JPiantedosi (Apr 23, 2012)

We have a small flock of kahtadin sheep (60+-). The flock is split between 2 farms one group is one ram with 22 ewes and the other herd is 4 rams with 25ewes. 

Of the 2 groups one group has averaged about 60% ram lambs, and the other has averaged 75% ewe lambs (the lone ram). We are trying to build a sizeable flock, so obviously we would prefer to have ewe lambs. Should we start to move along the rams which are throwing predominately ram lambs? is it just luck of the draw? or is it likely that one ram might be more likely the throw ewes over rams?

Jim


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## purplequeenvt (Mar 3, 2013)

The ram is what determines gender on the lambs. I know that there are people that think that certain rams throw a higher percentage of certain genders, but I've never found this to be true. Some years are ram years and some are ewe years. 

This year it was a ewe year in our Border Leicester flock (8 ewes bred to 2 different rams) with 9 ewes and 3 rams. It was also a ewe year with the Shetlands (3 ewes bred to 1 ram) with 5 girls and 1 boy, but it was a ram year with the crossbreds (8 ewes bred to 3 rams) with 7 boys and 3 girls.


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## bergere (May 11, 2002)

Just from what I have seen.... I had one Brecknock Hill Ram that threw nothing but ewes.
The other Rams were about equal.

The BWM Ram I had, just had boys when I owned him. Sold him. He's still throwing 90% boys even after 10 years. But the folks I sold him too, eat the boys, so its not an issue for them.

So if you can find a good Ram that throws a high % of ewes keep him.

Even know of a very pretty chestnut pinto Miniature horse stallion that has thrown nothing but fillies. So it happens.


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## Callieslamb (Feb 27, 2007)

hummmm. One of my rams threw all rams last year. He did the same thing this year.....hum...........?


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## Gritty (Nov 26, 2012)

You can google apple cider vinegar and sex determination in sheep (or something equivalent) and find a lot of anecdotes from folks saying that using acv not only improved overall health, but they had more ewe lambs. Other folks say its an old wives tale. I use acv in the troughs, but mostly to keep algae from growing and any additional benefits are always appreciated!


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## ErikaMay (Feb 28, 2013)

There are lots of factors that determine the sex: thats why no one has "mastered" it yet. If it was only breeding that trait into rams...well, with all our domestication I think by now someone would have breed rams to do just that. Of course there are genetic issues that can cause a male do make only one chromosome, but its usually a genetic defect and rare.

Diet affects the sperm. Weight (thin and skinny animals tend to have more males, heavy animals then towards females. Thus the "Rich Mans Dillemma" of only having girls when he wanted a male heir) does, too. The PH of the uterus affects the KIND of sperm that survives.

So yes you can choose a ram that seems to throw more females, but discount a really nice ram just because he has a few more males. I'd rather better genetics and a few less ewes (although I want ewes!) than more ewes with worse genetics.


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## InHisName (Jan 26, 2006)

so here is a question, what about a ewe that always has ram lambs? Does the ewe have any part in this? (purchased a lovely WensleydalexCotswold that only has thrown ram lambs, but hoping for a change. She was bred to a Gotland ram, so hoping for a ewe)


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## farmmaid (Jan 13, 2003)

Yes, ewes CAN play a part in the sex of the babies. Some have chemical differences in their uterus that favor one sex over the other. I have had goats for 40+ years and sheep for 4 years and my records show that male to female babies are about equal averaging over the years. I have had years with 60%/40% and I have years with 40%/60%. Last year was equal with the sheep and a doe year with the goats...............

We start lambing/kidding the end of February, no first timers this year so all have a birthing history in my farm journal....YAY!


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## dlskidmore (Apr 18, 2012)

In humans, the pH can vary during parts of the fertile days, and that in turn affects success rate of x vs y sperm. I'm sure there are lots of variables that affect exactly where in the fertile period the ewe is bred and her current chemistry. Perhaps some ewes display interest sooner or later in fertile window? Minor kidney issues affect blood pH, and probably also womb pH. Differing water consumption, even how hard you are breathing affects your short term blood pH.


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## lambs.are.cute (Aug 15, 2010)

I've always found that if I feed alfalfa hay at breeding time it will be 70+% males but if I feed only grass it will be 70% females. My grass usually holds out for breeding unless it gets cold early. It works for me and my neighbors but I have never talked to out of local shepherds to see if they have this too. 

I do have one exception to the rule though. This ewe lamb has thrown boys for 7 years in a row before she had one ewe lamb. She is a determined eater and only stops to chew her cud. She is fat most of the time and although she is the smallest by a large margin, even the biggest one moves out of her way when it comes to food. She breeds before I have to feed hay usually so why boys? I really don't know. Maybe she likes them?


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## thequeensblessing (Mar 30, 2003)

We have a 6 year old ewe who has had 4 sets of lambs for us. Every single lamb she's ever delivered has been a ram. She's been bred to 4 different rams (each breeding by a new ram) and every time she throws rams. Is it just the luck of the draw? I doubt it. Perhaps the PH of her body is more favorable to the Y sperm? No one really knows the answer yet. 
She's due in the next two weeks, and we'll see what she has this year.


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