By Shannon Linderoth | 3/15/2002
Reprinted from Dairy Herd Management Online
Dairy offices are awash with data. Whether you've got papers overflowing from filing cabinet drawers or details neatly digitized on computer disks, you're inundated with facts and figures. And thanks to technology, you can pull reports for virtually any of the records that you keep. Even if you are numbers-inclined, all of this information can be difficult to translate into necessary action.
However, monitoring your herd's reproductive performance from this fountain of facts doesn't have to be complicated, or time-consuming. Focus on a few key areas to determine whether your program is going according to plan.
This means dropping some measurement tools from your repertoire and adding others. By using five key areas to measure current herd performance, you can decide whether current performance meets your goals, and determine what management changes, if any, are needed to improve performance.
Traditionally, producers have used measures like average calving interval, average days open, annual heat detection rates and annual first service conception rate to judge their reproductive programs. But experts are skeptical as to the relevance of these parameters in making timely management decisions.
With average days open, for example, you immediately have an accuracy dilemma since you must decide which animals to even include in the equation. Do you include all cows in the herd for the time frame beginning with the most recent calving through the latest insemination? Do you include culled cows? Or cows you've elected not to breed? Or cows that have never been serviced?
There is no standard industry calculation, so accurate comparisons between herds, or even within herds if definitions change, become difficult.
The measurement also reflects significant lag time between current performance and past activity. And, it doesn't reflect individual cows with extremely high or low days open because everything is averaged.
"It's not the average of any measurement that's important," says Walt Ogburn, dairy sales consultant with Pharmacia Animal Health. "It's the distribution of the data that affects profitability."
5 Key Tools
"You're always looking backward with reproductive records," says veterinarian Mike Wolf of Menomonie, Wis. And reproductive management changes aren't usually quickly reflected in the bulk tank. To overcome these challenges and ferret out the most helpful information, begin with a performance overview using five essential records.
You can always dig deeper in the data if necessary, but the following areas will give you a leg up on what's happening reproductively within your herd.
- Examine annual pregnancy rate.
Annual pregnancy rate offers a good starting point because it factors in all cows in the herd and it emphasizes how the interaction between heat detection and conception impacts a dairy's reproductive performance.
"Pregnancy rate allows us to monitor how well we're achieving the goal of getting eligible cows pregnant," says Paul Rapnicki, veterinarian and associate clinical specialist at the University of Minnesota's College of Veterinary Medicine. Furthermore, it reduces dependence on average measurements with multiple definitions.
Use this figure to set realistic, incremental goals for your program. "However your operation currently performs, add about 10 (percentage points) for your goal," suggests Ogburn. "If you're at 15 percent for an annual pregnancy rate, aim to achieve 25 percent. "Yet, it's important the goals be attainable on your dairy with your management skills. If that means stepping up performance by 5 percentage points, then begin there before aiming for a 10 percentage point increase.
Your herd management software may calculate annual pregnancy rate, but if not, take the total number of cows becoming pregnant during the period and divide by the total number of cows eligible to get pregnant during the period. It's usually calculated for 21-day cycles, but can easily be figured on an annual basis. Break the data down by lactation group for closer examination of herd performance.
- Examine pregnancy rates for the most recent three 21-day cycles.
Data from this time frame enable you to discover trends as to where your program is headed. It looks at all recent breedings of all cows, indicating seasonal changes or if something dramatic has occurred with your breeding program.
"If you look at annual pregnancy rate, then at what's happened with pregnancy rate over the last 90 to 100 days, you can look at trends," Wolf notes. And spot opportunities to make changes if the trend is negative.
Results from the three most recent cycles would give you better feedback than the annual rate.
This measurement is also an indicator of positive progress. If your program is not faring well overall, but the last three cycles indicate improvement, you can go back and reinforce whatever changes were made to keep things headed in the right direction.
- Examine pregnancy rate for the first three cycles following the voluntary waiting period.
This is an indicator of the overall success of your program.
"Look for 20 to 30 percent pregnancy rates for at least two of the cycles. You won't have high annual rates unless high pregnancy rates occur in the first three cycles," Ogburn adds.
Marie Pagenkopf, of Sandy Acres Dairy in Elk Mound, Wis., and veterinarian Wayne Griffin monitor this by tracking the percentage of cows confirmed pregnant by 150 days in milk. Their goal is 80 percent, which means the 360-cow dairy achieves adequate monthly pregnancies to maintain herd size when they hit that target.
"This is a big deal to me," Pagenkopf insists. "I want to see us reaching our goal every month when we go over our records."
- Track voluntary waiting period (VWP) policy adherence.
Everybody involved in reproduction on your dairy should know when cows may be inseminated the first time after calving. However, plans are not always followed.
Learn when first inseminations are really occurring on your dairy and whether that's consistent with your policy. If there's a radical departure, you either need to correct the situation or revisit the reasons behind the current waiting period and make adjustments accordingly.
These data show how early an operation is willing to breed cows, says Ogburn.
And, the data depict whether the timing of your program is starting to lag and cows aren't inseminated until long after the VWP expires.
Inseminators at Sandy Acres Dairy consistently meet the management objective of breeding cows in a timely manner. "Our goal is to have 100 percent of cows serviced by 90 days in milk, and the records show we're at 100 percent," Griffin says.
- Monitor conception rate.
While not the primary tool in judging program success, conception rates remain a factor in reproductive programs. Just remember that conception rate is defined as the percent of services with known outcomes occurring in a given time frame that result in a pregnancy. And, you can have high conception rates with lower pregnancy rates if you're breeding fewer cows.
"Conception rates will usually not change quickly unless the problem stems from people or nutrition," says Ogburn. "Conception rate information can help you explore variables like who performed the inseminations and whether the insemination was based on a standing heat or a synchronization protocol. Then, you can look at different time periods and determine if anything has changed."
One caveat regarding reproductive records: Individual computer programs may define and track all of this information differently. Be sure you know how your program, or that of your consultant, interprets the data so you can accurately evaluate what the report means on your operation. This is especially important when comparing herd data between farms.
The best thing these reproductive records can do is create entry points for further investigation.
"Any time I examine a dairy's records, I end up with more questions as I go through them," says Ogburn. "But that's a good thing, because then we have a starting point for discussion and evaluation."
Ultimately, your reproductive program (and by default your reproductive records) must be able to meet two standards. First, you must be able to assess current performance. And second, you need to be able to monitor success toward your goals. This means you must choose the tools that best allow you to evaluate your program.
- Pregnancy rate: The percentage of cows eligible to become pregnant in a given time frame - usually 21 days, the typical length of an estrous cycle - that actually do become pregnant. Notice that there is no need to know heat detection rate or conception rate to figure pregnancy rate.
- Voluntary waiting period: The length of time herd managers choose to wait after calving to begin inseminating cows. Most dairies begin breeding between 45 and 60 days in milk.
- Conception rate: The percent of services with known outcomes occurring in a given time frame that result in a pregnancy.