Studs determine sex, Female determines #
 

I was just reading an article from debbie jensen's site and it said that the stud determines the sex of the puppies and the mom determines the number. I always knew that the female determined the number, but I don't remember ever hearing that the male determined the sex. Since there is definitely a higher demand for females - have you ever took into consideration whether a stud produced more females than males?

Well, that is logical because it is the same in humans. The father's sperm has the X and Y chromosomes and the mother's eggs are all X's...

The number depends on how many eggs mother drops at the time of conception.

You are totally correct on this, by my reasearch and vets. If I would consider a stud that produced more females.....no.....I think let nature take its course.

I have also heard the same thing. My vet verified this as well.

well it makes perfect sense. Males determine the sex because they carry the X and the Y chromosomes and females only carry the X. Females determine the size of the litter because the larger the female, usually the larger the litter. hence why yorkies have approx 3 puppies, and labs can have 10

I think it IS possible for some males to produce more females than males and vice versa. How do you know when picking out a male? You don't. With Chester, out of 9 pups, 8 were female and only 1 was male (2 litters). But, who's to say...could just be luck of the draw, temperature changes, etc.

It IS possible for some males to produce more males and vice versa. Still basically the conditions along with the amount of "x" and "y" in the male. They may have strong "x" or strong "y".

The timing of the breeding could make a difference too. There are normally more male sperm, and they are better swimmes, but the female sperm live longer. So if bred when the eggs are present, chances of getting a male are better. If bred before the eggs are present the better chance of getting a female.

Good point.

The sperm carry the chromosomes and they live as long as they live whether or not the ova are present..I don't think there are male sperm and female sperm. Each sperm carries chromosomes X and Y so the timing might not have any effect on the sex of the puppies.
I know a bit about genetics of both humans and animals but not an expert. Would someone let me know if there is a source of info for this.
Maybe Stacy will see this and can add her expertise..

I found this which does support JeanieK's post.

The sex of your baby is established at the moment of Conception. Dad's sperm chromosome compliment determines sex of baby. It is dependant on whether a "Y" chromosome containing sperm fertilizes the egg or an "X" chromosome containing sperm fertilizes the egg. Mom only has one type of egg - one with an "X" chromosome. If a baby has 2 "X" chromosomes, it's a girl. An XY chromosome pair is a boy.

The XX sperm ( female) tend to 'swim' slower, but live longer. The XY sperm (male), 'swim' faster, but die sooner. That is why it is said, if a woman is trying for a girl baby, to have sex a few days before her fertile day, that way when her fertile day comes, all the male sperm would have died off, leaving only the female sperm. If try for a boy, it is recommened to have sex only on the fertile day.

Some studs seem to know intuitively the ovulation timing so I guess those studs would most likely produce males. One that is not so intuitive may breed before actual ovulation, thereby producing more girls. I guess you could influence the sex to some degree through ovulation testing and controlling the fertilization process by artificial insemination.

The male chromosome pair are distinctly different from each other, therefore referred to as the X and the Y. The two sex chromosomes of the female resemble the X of the male, and are essentially identical. The female chromosome pair are both referred to as X. During meiosis the members of every chromosome pair are split up as the gametes form. All the female ova gametes have a single X chromosome. The male gametes (sperm) are equally divided with X- and Y- bearing cells. Should the female ovum be fertilized with an X- bearing sperm, a female puppy will develop. An ovum fertilized by a Y- bearing sperm will form a male puppy. So it is the sire alone that determines a puppy's sex. The other traits will not always be determined by the sire.

http://www.barkbytes.com/medical/med0084.htm

Does everyone follow the protocol of 10th, 12th and 14th day mating? If you only mate once it would seem that the majority of puppies would be female since the female sperm live longer. Has anybody noticed this being the case when only having one mating?

With my last litter of 7, there were only 2 matings in a row. One on day 10 and one on day 11. We have 4 girls and 3 boys.