You may remember that we were trying out a technology called sexed semen, but we had limited success with our first go-around. Not easily discouraged, though, we forged ahead with a more aggressive approach. This time, we carefully selected bulls that we expected to have better than average conception, and we committed to breeding all of our AI sired heifers with sexed semen for their first two services. We also selected bulls specifically for matings with the heifers that we would be breeding in the coming months. The first two bulls that we used were Petrone and Grafeeti; primarily selected for use on Sanchez and Trigger heifers, respectively.

Preliminary Results

We had much better conception this time around, with 4 pregnancies each from 10 units of each sire. We’ve stuck to our plan pretty well, using sexed semen for two attempts and using conventional semen on the third and subsequent attempts. On some older heifers (who didn’t start cycling as early), we’ve instead only bred them with sorted semen on the first attempt in the interest of getting them bred more quickly.

Last week, Number 100, Zorba, our first “HD” tagged calf (sired by Planet) delivered our first Grafeeti heifer. This week Number 1134 (a January daughter) delivered twin Grafeeti heifers. Ironically, only one of our Grafeeti pregnancies is a Trigger heifer, but we’ve purchased 10 more units of Petrone (still for Sanchez’s and some others) and 10 units of Mogul (with Trigger in mind, although we’re using him on other daughters as well).

Disadvantages

Sexed semen does cost more than conventional, but heifers are more valuable than bulls. Also, the conception rates are reduced, but with these higher conception bulls, that disadvantage has been less obvious. By using this technology only on heifers, who are generally more fertile than lactating cows, we further reduce the impact of conception rate reduction. For us, the advantages of using sexed semen in our breeding program easily outweigh the disadvantages.

More Heifers

On a dairy farm, a heifer calf is significantly more valuable than a bull calf. Heifers grow up to be cows who produce milk, which happens to be what we sell. For our operation specifically, we hope to expand slightly, so raising more heifers will help us do that gradually and internally. We strongly prefer to not purchase cows to maintain and grow our herd because animals from elsewhere may have been exposed to different bacteria, raised on different feed or in different environments, and may have unknown genetic pedigrees. For these reasons, we would like all replacements to be heifers we raise.

Easier Calving

Calving is a big event in a heifer’s life. It can be very stressful on the new mother, and as with most things, we like to minimize that stress as much as possible. We use calving-ease bulls on all heifers to contribute, but having a heifer calf is also a big advantage. Bull calves are generally larger, and therefore harder to deliver, than heifer calves. By making sure that our heifers are having heifers, we’ve increased the chances that our first lactation cows will transition quickly and seamlessly into our milk herd.

Better Heifers

Note that we’re only using sexed semen on AI-Sired heifers. We’ve been using AI for 5 or 6 years now, and we’ve noticed the difference between AI-sired animals and herd bull sired animals. We have some great old cows sired by herd bulls, but we see much better consistency in AI cows. To more quickly improve our herd genetics and increase the percentage of cows in our herd with multiple generations of AI sires in their pedigree, we want heifers from our AI-sired heifers. I would like to note that genetics are important to us and we won’t condone a terrible mating in the name of having a heifer calf, so if the mating doesn’t work with the sexed semen we have on hand, we will use conventional instead. Better to have a 50% chance at a great heifer than a 90% chance an inbred or poorly mated heifer.

The Total Package

Really, all of these things work together, and we think the added expense is worth it for the total package. The Bullvine recently wrote an article with some thoughts and guidelines regarding the use of sorted semen, and I loved reading it because I believe that our use is in-line with those suggestions. Heifers having heifers helps us improve our genetics efficiently, grow our herd gradually, and transition our bred heifers into cows more smoothly, and we hope that sexed semen will pay major dividends over the next few years.

Related articles by others

• Fall Service Sires (dairyxbred.com)
• Highlights from Applied Reproductive Strategies in Beef Cattle Symposium 2013 (absbeef.wordpress.com)
• A day in the life of a Dairy farmer(‘s wife)… a follow up lesson. (milkandkoekjes.wordpress.com)