We are experiencing an unually high open rate in our herd. ( 30 open for 200 <br>cows)<br>Our cows should begin to calve around the first of Febuary, but some have <br>been predicted by the vet to calve in late June! One or two in <br>understandable but 30! We use eight mature bulls. What factors can be <br>causing this? We don't grain out bulls and they may not be as fat as others <br>when they are turned out to breed. Also we don't have a regular mineral <br>program, just salt.
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I agree, 15% is a bit high, but actually not that unusual. Several things should be checked out. <br>1) Minerals--cattle need them, get an accurate assessment for exactly what your cattle require. Some of the ones off the top of my head re: fertility are Cu, Mn, etc but these can EASILY be overdosed.<br>2)Disease: things ranging from Mycoplasma, Ureaplasma, Campylobacter, to virals such as BVD to some parasites (decrease pregnancy rate from sapping nutrients) can drop your rate.<br>3) Bull conditioning--running 8 bulls on 200 head shouldn't make this one as serious as long as you know each bull is fertile and not subfertile, which would make other bulls work harder to get the job done.<br>4) Other factors which you should go over with your vet....every herd is individual and there's no way of predicting which you have at your place...<br>You should have at least 75% 1st service conception rates if all of the above are correct, then another 10% next cycle, so if your breeding season were only 42 days, you'd get at least 85% conception. Don't ever expect 100% conception, but it's nice when you do get it. Sorry to be so vague on this, but it's highly individual to the operation. <br>Good Luck<br>Vicki<br>: We are experiencing an unually high open rate in our herd. ( 30 open for 200 <br>: cows)<br>: Our cows should begin to calve around the first of Febuary, but some have <br>: been predicted by the vet to calve in late June! One or two in <br>: understandable but 30! We use eight mature bulls. What factors can be <br>: causing this? We don't grain out bulls and they may not be as fat as others <br>: when they are turned out to breed. Also we don't have a regular mineral <br>: program, just salt.<p>
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Several questions come to mind. Have all of your bulls been fertility tested annually? Have they been tested for sexually transmitted diseases? Have you introduced new stock to your herd?<p>What about your vaccination program for sexually transmitted diseases? Are all of your animals being vaccinated properly? Two injections properly spaced when called for? Proper care of vaccine - refrigerated & used promptly with clean needles?<p>How many heifers vs. mature cows in your herd? What was the body condition score of your cows going into the breeding season? Were they on a gaining plane?<p>Are you animals wormed on a regular schedule and with a wormer that will kill flukes if they are present in your area? Liver fluke infestation can delay puberty in heifers. <p>Are there new bulls in your herd? Did they had time to establish their pecking order before breeding season began or were they still fighting and fussing when they should have been breeding cows?<p>I think it would make sense to spend a few dollars on the eight herd bulls first. Have them examined for breeding ability and fertility. <p>A good free-choice mineral supplementation program is a good idea, too. <p>Why are you leaving your bulls with the herd for 4+ months? With your ratio of bulls to cows as high as it is, all cows should have been bred within a 60 day period. Suggest you work with your vet to rule out disease or other breeding problems, then establish a 60 day breeding season, pull your bulls, then cull all open cows at preg checking. This will accomplish two things. You will be keeping only your most fertile cows, and your breeding season will be tightened up instead of strung out. <p>So, look at nutrition, disease, & physical ability to breed, and see if you can tell where the problem might lie.
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