Big variation in conception rates to AI bulls

[Matt23]

Hi, I’m new to AI’ing and I’ve been using different Holstein sires from various AI companies over the past year and a half and I’m seeing big variations in conception rates to different bulls and was wondering is this common?
For example I’ve used 30 conventional straws from one bull with over 20 confirmed pregnancies and yet there’s another bull that I’ve used 30 conventional straws from with only 10 confirmed pregnancies.
Is this common or is it just bad luck for the latter of the two bulls?
I also seem to get higher conception rates with certain sexed bulls than I do with other conventional bulls straws
Thanks in advance for any replies!

 

[TheRanger]

Probably not a large enough sample size to draw any meaningful conclusions

 

[frederick]

Hi, I’m new to AI’ing and I’ve been using different Holstein sires from various AI companies over the past year and a half and I’m seeing big variations in conception rates to different bulls and was wondering is this common?
For example I’ve used 30 conventional straws from one bull with over 20 confirmed pregnancies and yet there’s another bull that I’ve used 30 conventional straws from with only 10 confirmed pregnancies.
Is this common or is it just bad luck for the latter of the two bulls?
I also seem to get higher conception rates with certain sexed bulls than I do with other conventional bulls straws
Thanks in advance for any replies!

You also have to be careful that your bull matching hasn't created this.
I've had sexed semen conception in hight to mid 60s bit at the same time triple blue at 54.
However I chose the most fertile cows for sexed usage.

 

[Kiss]

We test the batch before it goes anywhere near a cow

still get variation but shouldn’t be any total disasters!

 

[Borney92]

Hi, I’m new to AI’ing and I’ve been using different Holstein sires from various AI companies over the past year and a half and I’m seeing big variations in conception rates to different bulls and was wondering is this common?
For example I’ve used 30 conventional straws from one bull with over 20 confirmed pregnancies and yet there’s another bull that I’ve used 30 conventional straws from with only 10 confirmed pregnancies.
Is this common or is it just bad luck for the latter of the two bulls?
I also seem to get higher conception rates with certain sexed bulls than I do with other conventional bulls straws
Thanks in advance for any replies!

Hi Matthew

Generally bulls all differ in their conception rates but all have passed the quality test.
In the trial done by teagasc on sexed semen, it was found that some bulls sex better than others and same goes for conception rate.

As for why one batch of straw held better than the others there could be any amount of reasons.

Weather,feed,Dim, calving difficulty ect

Just keep on practicing.

 

[Matt23]

Thanks for the replies, I know my small sample isn’t large enough to come to any conclusions over so that’s why I wanted to get others opinions. It probably is more to do with the cows fertility than the bulls, I just find it strange that I can get better conception rates with sexed than certain conventional semen

 

[O'Reilly]

I buy a few straws from a lot of bulls, just to reduce this risk. Conception varies from zero to 100% every year.

 

[jerseycowsman]

Thanks for the replies, I know my small sample isn’t large enough to come to any conclusions over so that’s why I wanted to get others opinions. It probably is more to do with the cows fertility than the bulls, I just find it strange that I can get better conception rates with sexed than certain conventional semen

We find variations, some bull semen is definitely more fertile than others