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♦ A Management Tool to Reduce Days Open
♦ A Management Tool to Reduce Days Open

By Louis Guilbault, Ph.D., Vice President of Business Development, Conception

Quick identification of open cows is a priority, and there is a good reason for this; the cost per extra day open ranges from $3 to $5.50, according to researchers at the University of Florida, and is a heavy burden for producers.

The goal of a pregnancy diagnosis is to find open cows, not to make sure cows are pregnant. In that respect, the easy-to-use DG29 bovine blood pregnancy test is nearly 100% accurate for identification of open females as early as day 29 of gestation. DG29 can be used as a complement to more traditional procedures of pregnancy diagnosis (i.e. rectal palpation or ultrasound) or as a stand-alone pregnancy diagnosis procedure. When used efficiently, DG29 allows for significant reduction in the number of days open, shortening of the interbreeding interval and higher profitability on the farm.

Dairy producers want to maximize the number of animals pregnant during each 21-day period commencing at the first service (i.e. 21-day pregnancy rate). To reach that goal, quick identification of open cows within the next 21-day period (i.e. within 42 days after breeding) for resubmission to early rebreeding is critical. The objective is to reduce the interbreeding interval (the time between inseminations) to less than 42 days in as many cows as possible. Today, the average interbreeding interval is approximately 50 days on U.S. dairies. DG29 can assist in reaching reduced interbreeding intervals.

While considering implementation of DG29, don't become overwhelmed by the challenge of introducing a new pregnancy testing strategy. Instead, consider how it can fit within already-established reproduction management practices. To be a true asset, DG29 must only imply small managerial changes in the farm setting.

Here is an example from a Canadian dairy farm that stands to make significant gains through DG29. The farm is comprised of 480 cows in lactation and has excellent reproduction management. Cows are bred via artificial insemination (A.I.) on natural heats and following Ovsynch. Pregnancy checks are by rectal palpation at two-week intervals for animals 35+ days post-breeding. With this regimen, cows 29 to 34 days post-breeding are not checked until the next scheduled palpation session two weeks later; these animals are well over 42 days post-breeding by the time they are initially identified as open or pregnant. Over time, a large proportion of the herd (~50%) will not be preg checked until after the second 21-day period (i.e. after day 42) which impacts farm profits considering costs per extra day open.

Without changing the routine of preg checking cows at two-week intervals, DG29 improves reproductive performance and decreases the breeding interval in this herd. Here's how: At the same time cows 35+ days post-breeding are palpated, the producer can take blood samples from cows 29 to 34 days post-breeding (Figure 1A). As a result, there will be a minimum gain of two weeks to identify open cows that otherwise would not have been preg checked until much later (day 43+). This can be accomplished with only small managerial changes.


Once the producer sees the benefits of DG29, a more radical application is to preg check all cows at weekly intervals using DG29. This method translates to additional gains through fewer days open; all cows are preg checked before the second 21-day period and average days open on the farm decrease even more significantly as compared to current practices. The higher the frequency of pregnancy diagnosis through use of DG29, the greater the economical impact on the farm.

Now look at a Wisconsin dairy farm with 1,025 cows with an annual average pregnancy and conception rates of 26% and 43%, respectively. Breeding is done on natural heat or at a fixed-time following a Cosynch + EAZI-BREEDTM CIDR® synchronization program. The farm manager ultrasounds animals 31 and 45-50 days post-breeding on a weekly basis and the veterinarian palpates animals at 80 days post-breeding.

The first opportunity for DG29 is to take blood samples from cows at days 29 and 30 post-breeding at the same time the farm manager ultrasounds animals that are at day 31+. By continuing to DG29 test those animals 29 and 30 days post-breeding week after week, a significant proportion (~22%) of cows are preg checked a week earlier (Figure 2) than under the previous practices. This improvement in reproductive performance required only small operational changes.


The herd manager could switch from ultrasound to DG29 preg checking all animals at day 29 or later. The switch would free up time for the farm manager because an employee could collect blood samples. Of course, the veterinarian would continue to check cows that are 80 days post-breeding on a weekly basis, but with a greater focus on open and problem cows.

Here's one more real-life scenario. There is a dairy in Texas with approximately 2,800 cows and a 27% pregnancy rate. The dairy's reproduction protocol, illustrated in Figure 3, includes the herd manager preg checking cows at days 36-42 post-breeding. However this herd has an aggressive breeding strategy and A.I. can occur quite early after calving. Therefore, days in milk (DIM) is sometimes less than 90 when cows would be preg checked using DG29. To avoid the possibility of false positive results (only 2-3% between 80-90 DIM), it is recommended all cows are at least 90 DIM when blood samples are collected for DG29.

Still, use of DG29 can improve profits and reproductive performance. Here's how: The herd manager continues the routine of preg checking cows following their first A.I. (i.e. palpation or ultrasound at days 36-42 at weekly interval), but then uses DG29 to preg check cows following their second or greater service (A.I.-2 and A.I.-3) as early as 29 days after A.I. (indicated in red in Figure 3). As a result, a large proportion of cows (up to two-thirds) at their second and greater services are preg checked at least seven days earlier (days 29-35) than with the previous practice (days 36-42). This represents a fair number of cows since the conception rate at first service would average 35 to 37% in such early bred cows, according to university researchers.


With DG29, improvements in reproductive performance can be achieved with minimal managerial changes, but most importantly, it translates into additional farm profits. Take the Texas dairy, in this scenario saving seven days open per cow on two-thirds of the herd turns a potential profit of $42,000 to $71,000, given a cost per day open of $3 to $5.50.

Today, DG29 is used by thousands of satisfied customers in North America, Europe and the Middle East. Its practical and economical advantages make it a very convenient tool to maximize profitability at the farm.