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Drought in 2006 Leaves Challenges for 2007 Calving

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Posted Apr. 15, 2007

Don't worry about drought in 2007 we're not finished with last year's yet, and here's why. Generally, cow herds in southern Oklahoma and north Texas went into this winter in lower body condition and were asked to subsist on less and lower-quality roughage than at any time I can remember.

These cows are now calving and facing this breeding season in critically low body condition. Body condition score (BCS) 4 is the rule, with BCS 3 common, and the minimum target of BCS 5 almost nonexistent. We're set up for disastrous conception rates in spring-calving herds this year. Some people experienced this last year, and we're in worse shape now.

A cow calving in a BCS 4 or less will be longer to first estrus compared to the BCS 5 cow. Also, she'll be less apt to actually conceive until she has nutrition above her needs for maintenance and milk production. Table 1 illustrates both points.

Both trials measured reproductive performance relative to BCS at calving. Trial 1 showed only 62 percent of BCS 4 cows were even cycling at 80 days after calving. To stay on a 365-day calving interval, they should be bred by that time. Trial 2 drives home the second point. Cows in BCS 4 or less at calving probably won't rebreed in acceptable numbers unless and until they add condition at least up to a BCS 5, regardless of how long you leave the bulls out (six months in this trial). There are many other trials like these with similar findings.

What can be done? There are at least two practices that have been proven to help increase conception in thin cows. One is "flushing." Right now, cows should be getting nutrition above their needs for maintenance and milk production. Flushing is increasing nutrient intake significantly above requirements for maintenance and lactation so the cows are in a positive gaining mode of one to two pounds per day. It can be accomplished with feed, high-quality hay or small grain pasture. Ideally, flushing thin cows begins two to three weeks before the breeding season. By itself, flushing can help improve conception rates. Its success can be enhanced, though, by using short-term calf removal shortly before turning the bulls out. When calves nurse, estrus is suppressed. Removing calves for 48 hours or so "jump-starts" the hormone cycle that brings on estrus.

Reproductive performance has more to do with profit than any other factor, and it all starts with conception. Do whatever is necessary to ensure a high conception rate this spring and summer. If you need any more information on these or other practices, call a Noble livestock specialist at (580)224-6500.