by Gabe Middleton, DVM
Some producers have suggested that reproductive efficiency is just something that “happens” and “is easily achievable.” There are many nuances to reproduction that can have a tremendous impact on dairy farm profitability. Reproductive efficiency is needed to maintain herd productivity.
The easiest argument that ties production to reproduction is that days in milk of the herd is clearly linked to productivity. If the herd is fresher, production increases. If the herd is more stale, production suffers. Consistent, strong reproduction leads to a more consistent, lower days in milk. The result is simple and repeatable. Lower days in milk means more milk.
First lactation reproductive efficiency begins before the heifer freshens. If a heifer is small at calving and does not transition well, reproduction is going to suffer for first lactation animals. Even if the heifer calves at an appropriate weight and age, breeding that animal is a point of discussion. Lactation curves for first lactation heifers tend to be very flat and they persist much better than older cows. For this reason, breeding first lactation heifers should be delayed longer than mature cows. It’s not unusual to see a voluntary waiting period of 80 – 90 days for lactation one.
Lactation two and above (mature cows) make up a greater percentage of the herd and their reproductive efficiency is also key to production. Typically, conception rate lags in mature cows relative to first lactation heifers, and their lactation curve falls off much more quickly. They do not persist as well as younger animals. For this reason, breeding mature cows earlier than heifers is recommended to reduce days at the end of the lactation when production is lower. Most voluntary waiting periods for mature cows are around the 60 days in milk range.
So what reproductive protocol is best to maximize efficiency? Time and time again, double ovsynch has been proven to not just be a synchronization program but also a fertility program. While it tends to yield the best results for first service heat detection and conception rates, it also involves giving six injections and requires the most labor. Herds that have adopted double ovsynch tend to never look back. The results are excellent and it’s worth the extra cost of hormones and labor.
Other synchronization programs can offer good results as well if double ovsynch does not fit your management capabilities. Activity monitoring systems also offer an advantage of increasing heat detection and determining what cows have not shown heat and therefore may benefit from a more aggressive synchronization program. What program is best? The answer comes from a collaborative discussion from veterinarian, herd management and the breeder.
There is often a glaring reason why days in milk increases on most farms: heat stress and summer breeding. Summer months tend to delay pregnancy in eligible cows. This backlog of cows that need to conceive causes an increase in days in milk after those cows conceive at a later date when heat stress has been reduced. Sometimes heat is too much to overcome, however. There are often bottlenecks in the heat abatement program that can be glaring and costly. The challenges with reducing heat stress can occasionally be a simple fix. Making sure fans are working properly, sprinklers are fully operational and the holding pen has excellent air movement and water are key factors in reducing the impact that heat stress can have on both production and reproduction.
If reproduction is so important to dairy farm profitability, what is the best way to monitor success? By and large, the 21-day pregnancy rate remains the best metric to determine reproductive success. This number combines both heat detection rate with conception rate. Conception rate can be broken down by lactation, days in milk, breeding trigger, etc. This can help provide insight into how each area is performing; however, when 21-day pregnancy rate is excellent, typically reproduction is being maximized on the dairy. A goal for pregnancy rate is herd specific, but most well-managed herds can typically achieve numbers nearing or above 30%.
To provide the dairy with the best opportunity to maximize production and profitability, days in milk needs to be low. Reproductive efficiency takes effort, monitoring and solid decisions. Focus on reproduction and don’t just assume results will fall in place. Give your cows the best opportunity to succeed.