Rogers Ramblings – Spring 2021
In this article I would like to continue with the discussion around genetic gain.
It is exciting times for our breed at present with the introduction of sexed semen. Just imagine if we could keep most of our replacement heifers out of the top half of ourherds. I would encourage our breeders to use some sexed semen. If there is demand, we may get the opportunity to offer some more sexed semen from a variety of bulls.
Here at Lodore, we plan to use 50 straws of sexed semen from Super Sonic. With the idea of using 25 straws over our yearlings and 25 straws on the cows. With the reduced in-calf rate, say 60%, and a heifer rate of 90%. We are likely to generate 27 heifer calves. Compare that to the national average of 2.4 heifer calves for every 10 straws used equals 12 heifers. Add into the equation that the 27 heifer calves are out of the higher indexed group of cows and heifers gives an even higher rate of genetic gain.
However, it is quite expensive, and the in-calf rate may be reduced slightly. The cost of a normal straw of proven semen is around $20. So, allowing for 12 heifer calves per 50 straws used, the semen cost per heifer calf is $83.33. With sexed semen costing $56 per straw, the semen cost per heifer calf is $103.70. The other cost to consider is the slight reduction in early calving cows, due to the lower in-calf rate.
We intend to start mating a bit earlier than our normal plan start of mating to reduce the affect of the lower in-calf rate. The handling of the semen and the timing of the insemination can be critical to get the best outcome, so attention to this is very important.
So, which animals will I mate to sexed semen? Obviously, I would choose the higher producing cows with good high PWs. Then I will also consider their ability to get in-calf early and whether they have had a good pre-mating heat. The yearlings will be offspring of the above type cows.
The other thing to consider is when we have a higher number of heifer calves being born, there is less need to mate as many cows to Ayrshire semen. The use of more beef semen over the lower end of the
herd gives the opportunity for more calf sales and a reduction of bobby calves.
Another opportunity to speed up the breeds genetic gain is to increase the use of Genomics. However, I will leave this topic for another time. As always, I am happy to discuss my opinions further if anyone feels inclined to. My email address is lodorefarm@gmail.com
Roger Hutchings | Lodore