Your repro numbers might be flying high at the current moment. And today’s market conditions might lead you to believe genetic selection for female fertility seems less critical than it once was. But it’s important to remember: The genetic decisions you make now will impact the fertility and profitability of your herd several years down the road.
Management plays a lead role in achieving elite reproductive stats – and in creating more of those healthy, fertile, four-event cows with records that only show “fresh,” “bred,” “confirmed pregnant” and “dry.” But it’s impossible to deny the measurable results that can be attributed directly to genetics.
Creating your fertile herd of the future
If a herd of fertile cows and heifers is your goal, then you may want to consider Daughter Pregnancy Rate (DPR), Cow Conception Rate (CCR) and Heifer Conception Rate (HCR) as three traits to emphasize in your farm’s genetic plan. Here’s a quick breakdown of what the traits mean and what they measure.
1. Daughter Pregnancy Rate (DPR)
The percentage of non-pregnant cows that become pregnant during each 21-day period. A DPR of 1.0 means that daughters from this bull are 1% more likely to become pregnant during that estrus cycle than a bull with an evaluation of 0.0.
2. Cow Conception Rate (CCR)
A lactating cow’s ability to conceive. It’s defined as the percentage of inseminated cows that become pregnant at each service. A bull’s CCR of 1.0 means that daughters of this bull are 1% more likely to become pregnant during that lactation than daughters of a bull with an evaluation of 0.0.
3. Heifer Conception Rate (HCR)
This is a virgin heifer’s ability to conceive – defined as the percentage of inseminated heifers that become pregnant at each service. An HCR of 1.0 implies that daughters of this bull are 1% more likely to become pregnant as a heifer than daughters of a bull with an evaluation of 0.0
The proof is in the pregnancies
To see how these traits play out in reality, we dug into the management data from a 2,800-cow Holstein dairy. This herd keeps accurate records and sire identification, and their repro program is top-notch. In fact, they maintain a 33% annual pregnancy rate and 44% conception rate across the entire milking herd.
Below, you’ll see three different tables that show how genetic values for the three female fertility traits – DPR, CCR and HCR – make a measurable difference in this herd’s ability to create more pregnancies.
To get the data in Table 1, we separated the first-lactation animals from this 2,800-cow herd into quartiles, based on their sire’s value for DPR.
We then compared the 21-day pregnancy rate of the group with the highest average sire DPR to the 21-day pregnancy rate of the group with the lowest average sire DPR – and we expected to see a difference of 3.5%. What this herd actually achieves is a 6% pregnancy rate difference between the high and low groups for sire DPR. For reference, the pregnancy rate across all first-lactation cows is 36%.
Table 2 compares the Cow Conception Rate value for each animal’s sire against actual conception rates.
When we compared the top 25% of first-lactation cows based on sire CCR with the bottom 25% for sire CCR, we expected to see a conception rate difference of 4.2%. What this herd actually sees in their data is double that, with a 9% overall conception rate difference between the high and low groups for sire CCR.
Table 3 illustrates the most extreme benefit beyond genetic selection.
Here, we compared conception rates in heifers to the Heifer Conception Rate value for each animal’s sire. We expected the top 25% of heifers for sire HCR to have an average conception rate 3.2% higher than the bottom 25% of heifers for sire HCR. This herd’s data proves an actual difference of nearly three times that genetic expectation, with a 12% overall conception rate difference between the high and low groups for sire HCR.
The real numbers from this herd speak volumes. We see proof in the fact that bulls with higher genetic values for DPR, CCR or HCR truly create more fertile daughters. Because of solid management and an elite reproductive program, this dairy gets even more than what they expected – and these three pieces of the genetic puzzle get them one step closer to creating a more fertile future herd.
Your decisions today affect your future
If you think your repro program is invincible, just consider your results five years ago. Chances are, your pregnancy rate and conception rates are higher now than they were back then. While management practices certainly play their role, you can’t ignore the measurable difference genetics have made on that improvement in fertility.
Using sires with high values for DPR, CCR and HCR in your breeding program lends way to a more fertile future herd. Conversely, by ignoring these traits, you’ll likely take a few steps backward on your future reproductive performance.
If you have accurate sire identification and well-kept management records on your dairy, you can find proof in the power of these traits in your herd as well. Just ask your trusted genetic advisor to help you evaluate your own data. Then consider the impact of selecting for DPR, CCR and HCR. Include any or all of these female fertility traits in your farm’s genetic plan to continue building a profitable future herd of healthy, fertile, four-event cows.
PHOTO: Getty Images.
- Marketing Manager
- Alta Genetics
- Email Chrissy Meyer