Checking cows for pregnancy is an essential component of reproductive efficiency. However, most articles about the value of pregnancy diagnosis focus on identifying the open cows and getting them off the feed bill. With carrying cost being greater than $2 per day over the winter, there is a lot of value in that approach. And really, that’s about all many producers expect from the preg check process.
But there is more we can do with preg check information. We can make money with it, or at least be more efficient by spending less.
And there’s lots of money being left on the table. According to the 2007 NAHMS study, only about 20% of all operations used palpation or ultrasound to pregnancy test their cows. The blood test wasn’t available at that time. Just using preg check information to get the freeloaders off the payroll will help the bottom line of the remaining 80%.
However, focusing only on the open cow misses part of the value of the procedure. Using the information to manage the pregnant cows for optimum fertility can pay real dividends in this high calf market.
How to use the preg-check data
To effectively use data to manage cows in the dry period, there are several essential pieces of information required at preg check other than cow ID and pregnancy status: cow body condition score (BCS) on a scale of 1-9 with being 2 dangerously thin and 9 being obese, weight if scales are available, age, condition of teeth if an aged cow, udder and hoof condition, any injuries, lameness or other signs of external problems like a bad eyes and estimated days pregnant.
Blood tests will give you a yes, no and maybe result, but ultrasound and palpation should give you estimated days pregnant. Ultrasound is most useful prior to 120 days of pregnancy to determine fetal age. A trained, experienced palpater can accurately estimate gestational age. The procedure needs to be performed early enough to allow sufficient time to make management changes if needed (usually at least four months before calving). Producers often have it done around the same time as weaning or calf preconditioning.
Then you can start to manage your cows using your preg-check data. After preg checking, there are two groups of cows: the pregnant cows and the opens. But there are subgroups of those. In the pregnant cows, there are the first calf heifers, middle-aged cows and aged cows. They can be further divided into cows in adequate body condition and those that are thin. Then there are the early-bred cows, cows that will calve in the middle of the season and the late-bred cows. Using this information to manage high-risk groups will improve the health of the calf crop, fertility during the next breeding season, the profitability of future calf crops and longevity of the cows.
Cows that consistently calve early every calving season are the all-stars. They are the ones that often wean the biggest and best calves. The early-bred cows and cows that will calve in the middle of the calving season in good body condition (BCS 5 or better) don’t require much management. They just need to be managed to maintain their body condition and calve in a clean environment. More than 80% of cows that calve with a BCS of 5 or 6 and do not lose condition after calving are cycling by 60 days post-partum.
The cows that are in thin body condition are the concern. They need more groceries in order to be successful. There’s plenty of research that shows cows that calve with a body condition score of 4 or less may take as long as four months to cycle back after calving and even longer if they lose body condition after calving. That increases her risk of breeding late or not getting pregnant and leaving the herd earlier than planned.
Managing those thin cows to gain weight during the dry season can shorten the time it takes to cycle and breed back after calving. Depending on cow frame size, mature body weight, forage quality and availability, it may take two to three months for a cow to improve one body condition score during the dry period on forage alone (1 score = approximately 80 pounds). Supplementing thin cows during the dry period to gain weight is a good investment since it can enhance her chances of breeding back after calving, plus it can improve colostrum quality as well as calf health. If cows are very thin, it might pay to wean the calf early and provide high-quality feed through calving and lactation.
Advantages of sorting
A couple of advantages of separating pregnant cows into management groups at pregnancy check by BCS and estimated calving period are these: thin cows and first calf heifers can be fed more intentionally and efficiently and late cows can be kept separate from the earlier-bred cows. Keeping calving groups in separate pastures helps reduce the contamination of the calving area during calving. Scours typically don’t affect the earlier-born calves as much as the later-born calves. If these cows are already in a separate pasture, they aren’t exposed to the increased pathogen load of a contaminated calving area.
Old cows or cows with bad udders, hooves, are lame or have other problems like bad eyes may need to be culled, depending on the severity of their condition. Producers may want to keep them and get that last calf if they are bred early. It may not be practical to calve these cows separately, but having them identified for extra attention at calving time may increase chances of a successful calving. Also, depending on how many of these cows are in the herd, producers may opt to keep them as a separate group and not waste valuable bull power on them in the breeding season since they are tagged for culling at weaning anyway.
Managing cows according to BCS and expected calving period will improve fertility. But whether it is practical or not to manage separate cow groups prior to calving likely depends on available facilities and labor.
But it’s worth the effort. Reproductive efficiency is the single most important factor affecting productivity and profitability, and the success of a breeding season is most affected by how the cows were managed in the dry period before calving. Economic sustainability of the ranch depends on efficiently managing our cows to get an optimum return on our efforts. Using data to manage our cows improves production, efficiency and longevity of our cow herd and can have a positive impact on calf health.
Lee Jones , DVM, is an assistant professor and case investigator with the University of Georgia College of Veterinary Medicine at the Tifton Veterinary Diagnostic Lab in Tifton, Ga. Prior to joining the University of Georgia, he was in private practice in Nebraska.
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