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Is Fertility Heritable?

My mentor and neighbor had a bull that gained 4.54 lbs. per day on a grazing test a few years back. He had an extremely large scrotum (about 44 cm at 18 months), his motility was excellent.........but he wouldn't jump the steer at stud. Had to collect him in the chute where he would deposit "vast quantities" :lol: of semen.

When the owner put him in with cows he would not breed. Had no desire.

Had NO Libido.

Is he fertile?
 
Excellent example Mike.

There are many factors that influence which cows to keep and use.

I have not seen a libido EPD.

My vet was telling me about new research that shows there are as many concerns with very large scrotals in bulls as there is with small scrotals. The semen quality suffers in many cases with either too big or too small.

Yet for years we have all been told to use larger scrotal bulls for the fertility aspect. Common sence still is the best commodity.
 
I have heard the same thing about large scrotal bulls. What would
be considered too large on a yearling bull? 40? 44?

The last two heifer bulls we bought this spring are very amorous.
They are in with another bull that is 18 months old and he doesn't
show that nothing like they do. They'll get turned out Saturday...
I'm sure they can hardly wait.
 
The scrotal on yearlings depends who is measuring them.

My vet studied in the States and says he can run the tape over the scrotal of a bull without touching skin with the measure most US vets give. In other words they don't squeeze the scrotal tape at all. He uses a tape designed to measure babies heads at birth and puts decent pressure, not enough to cause major discomfort, but enough to test how firm the testes are.

40 is considered a very high yearling scrotal. However based on who is measuring them, it could be far less in real terms.

Measured with moderate pressure, the ideal range is 34 to 36 with no problem with the 32 or the 38 and even the odd 40.

That being said it doesn't mean every bull with a large scrotal will have more defects, it just increases the chances.

I also feel that a large swinging scrotal will get injured more easilly than a smaller tighter one, but it needs to be able to allow cooling of the testes.

If in doubt of the pressure to apply when measuring, a device called a coulter tape has a spring loaded measure and applies the same pressure on each bull. I pre measure my bulls to help with culling descisions.
 
Yeah the infamous slack tape measurements lol. I like to see the bulls eyeballs protrude a bit when the vet cinches it tight. As well a grainfed bull can have a bit of fat helping out his circumferance-thAt Hereford bull not only produced a large quantity of semen but it was also vbery high quality. I wonder when ,where and how the 20 percent figure was derived.
 
We won't take a bull that measures under 34 on a yearling, but the
folks we buy most of our bulls from (good friends and very honest)
maintain that length is never part of the consideration when scrotal
measuring. They say length can make up for circumference.

I guess eyeballing them is still the best, regardless of the measurements,
especially since all measurements are not created equal.
 
Eyeballing gives you the ability to not choose those that don't decend properly, those that decend too far.

I had a yearling picked out as a spare last year but when the vet measured him he was under 32 cm. Luckily I didn't need him as that is too small to be using to produce more bulls from. I was going to cull him, but he just kept on developing and this spring looked very nice. I had him tested, same vet, 38 cm scrotal and 94% normal sperm. I sold him the next day to a repeat customer who was thrilled to get a 2 year old instead of a yearling.
 

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