The problem with blood draw preg checking

angus9259

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At 30 days a cow has the pregnancy specific protein they check for. I checked said cow at 45 days and she came back as bred (had the right amount of the pregnancy specific hormone). She was in heat two days ago - even received the bull. If she slipped the calf at 30 days, the pregnancy specific hormone would still be in her blood and would come back as pregnant at 45 days even though she was open. If I had had her palped at 45 days, she would have checked open.
 
Yes it can send back false positives and that's why I do a recheck on all cows called pregnant. I read on BioTracking's website that if a cow loses the pregnancy at or before 30 days the protein is typically gone within a week. So if she lost her calf at 30 days she should show open if tested at 45 days. I realize there are several drawbacks to the blood testing but I feel it has it's place. I never use a vet for preg checking anymore because for similar money I can draw blood on my own schedule with as many cows as I want. After reading an earlier post on cows called open it also makes me realize how nice the blood test is as far as accuracy when called open. I believe it is 99% accurate when the cow is called open.
 
Here's the other side. Cow tested preg pos at 45, showed heat at 90, rested open at 120....saved me the wonder of whether or not to look for a calf in early Feb or not. Now expecting her to calve in late july from a later breeding
 
IF open those cattle should be cycling again by the tiem you get all the test results back. That's usually 100% accurate.
 
I wouldn't say cycling is 100% accurate. Had a cow cycling when we brought them home from pasture mid Oct. She was standing and I thought, shoot, that one is dry. Well, she was pretty pregnant when pregchecked a couple weeks later.....
 
randiliana":1hu35860 said:
I wouldn't say cycling is 100% accurate. Had a cow cycling when we brought them home from pasture mid Oct. She was standing and I thought, shoot, that one is dry. Well, she was pretty pregnant when pregchecked a couple weeks later.....
I've had a couple actually take the bull a couple weeks prior to calving but was she cycling?? She was doing absolutely nothin except "standing" . Don't know why the bull is attracted nor why the cow stands but she's not cycling. Maybe Lucky P the vet can help us out.
 
Makes me wonder about the cow I originally posted about. She was blood checked preg at 45 days. And stood for the bull (and other cows) at day 60 ish while there was another cow in pretty good heat. I never saw her stand at 21 days post ai, plus had the positive test at day 45 so I was pretty sure she was bred.
 
So how long does it take for the blood test results to come back?
Not that I'm in a hurry or anything...

I had about six or eight cows show up open this spring (September) - confirmed pregnant by vet with ultrasound scanner, a few were too short-bred to detect in February and were palped in April, all confirmed pregnant then, none observed cycling before June. I know (because I saw one cow with a full bag and palped a second myself, open but with swelling in the uterus) that at least two of those slipped their calves while at the grazier's in June. The remainder are a mystery - was the vet wrong? Did I truck them at an especially bad time of their pregnancy (about four and a half months for four of them)?

I like the idea of blood testing - if its close to 100% that those called open are open, that would enable some pretty fast decisions when grass is running short and it's too early to manually check, or for those observed cycling - especially the ones just kind of hanging around eyeing the bulling cows that are supposed to be well-pregnant.
Like Dun mentioned in the other thread, the vets can be extremely accurate on their dating. I don't tell mine the dates, I let them tell me and I have the matings listed in front of me. But I'm still consistently told of around 10% of cows 'held over' or sold on as open that calve within a few months.
 
Each lab tests on different days. The one I use tests on wed, and if I ship the sample monday, I get a call wed or thur
 

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