bovine scanning

Re: bovine scanning

James Kerr — Wed, 07 Nov 2012 15:09:26 GMT

[quote user="macflea"]

around here the guys who have dates when the cows were ai just want a yes or no and if scan matches their dates ie if not they repeated and they were caught by the mop up bull , its the guys who left the bull in for a few months and then removed the bull , who were told to scan before 15 weeks are now the guys coming back wanting dates etc.

boss got an ei medical scanner with goggles , a lot of button pressing to do anything . it would take ages per cow to start measuring things . i thought easi scanner 3 with goggles was the "one" to get . a bcf rep said roughly speaking once over 5 months

5 month 5 cm cotelydon , 6month 6cm cotelydon , 7 month 7cm cotelydon , you get the idea

but in reality how accurrate is this , can find no reference any where for this

i have no problem scanning less than 4 months or manual handling and guesstimating to within 2 months but since have scanner would get a sense of satisfaction if could improve the over 5 month situation

will have to do some cpd me thinks.

[/quote]

I did the embryonics advanced course and was told something similar to this, but it gets more variable the later on in pregnancy you get, only a rough guide really, and you need to find the biggest cotyledon, which can take a bit of time guddling around. The shape of cotyledons will give you a bit of info, tend to be mushroom-shaped at 4-5 months, rounded at 6-7 months and then flatter shape later on. But this is still very much a rough 'rule of thumb', I think if farmers are leaving things this late before scanning they can't possibly expect accurate dates.

Re: bovine scanning

Lucy Fleming — Wed, 31 Oct 2012 12:25:32 GMT

My understanding is that placentome size is too variable to be useful, and it looks like the conclusion of the study was the same:

"The high prediction intervals together with the significant effect of the farm on the placentome size make that placentome scanning is not useful to predict the gestational age of cattle."

Just keep plugging away at getting them to scan before 12 weeks!

Re: bovine scanning

Colin Thomson — Wed, 31 Oct 2012 11:00:45 GMT

[quote user="David Shepherd"]

just starting fremitus on pressure on the artery - 4 months

fremitus on touching the artery - 5 months

Strong continuous fremitus in the artery - 6 months

Fremitus in controlateral artery as weel - 7 months

Big pair of feet - 8 months (!)

[/quote]

Hear hear!

Re: bovine scanning

David Shepherd — Wed, 31 Oct 2012 10:13:00 GMT

As others have said, over 4 (?3) months you cannot see the foetus so no estimate is very accurate; anything more than a guess is just bulls**t! FWIW I find the old manual method of feeling fremitus in the uterine artery is as/more accurate than scanning for these heavily pregnant cows; ie;

just starting fremitus on pressure on the artery - 4 months
fremitus on touching the artery - 5 months
Strong continuous fremitus in the artery - 6 months
Fremitus in controlateral artery as weel - 7 months
Big pair of feet - 8 months (!)

David

Re: bovine scanning

macflea — Tue, 30 Oct 2012 22:19:39 GMT

michael you are the man , that's what i was looking for many thanks. that will keep me busy reading , its been a quite week .

Re: bovine scanning

macflea — Tue, 30 Oct 2012 22:19:37 GMT

michael you are the man , that's what i was looking for many thanks. that will keep me busy reading , its been a quite week .

Re: bovine scanning

Michael Woodhouse — Tue, 30 Oct 2012 22:17:42 GMT

There are some measurements in the PDF I linked above.

Don't know where you are in the country but Embryonics do some good courses. I haven't done the scanning ones but I have done foot trimming and embryo transfer with them and very impressed.

They are over in Cheshire.

Re: bovine scanning

macflea — Tue, 30 Oct 2012 22:11:27 GMT

5 month 5 cm cotelydon , 6month 6cm cotelydon , 7 month 7cm cotelydon , you get the idea

but in reality how accurrate is this , can find no reference any where for this

will have to do some cpd me thinks.

Re: bovine scanning

Michael Woodhouse — Tue, 30 Oct 2012 21:56:06 GMT

If you have a lot of spare time in your day - measure away

http://igitur-archive.library.uu.nl/student-theses/2011-1011-200705/version_research_project_Gerben_Blankenvoorde_Determination_of_gestational_age_in_dairy_cattle_using_transrectal_ultrasound_measurements_of_placentome_size.pdf

Re: bovine scanning

Michael Woodhouse — Tue, 30 Oct 2012 21:46:38 GMT

What sort of scanner have you bought? We have two scanners, an old Aloka and the old version of the Easy Scan.

The Easy Scan doesn't even have the ability to measure anything. The Aloka has the function but never used the function.

You get your eye in very quickly if you are scanning cows with dates, and I would expect to be within a few days 4-10 weeks. Once you get further on the less accurate you become. My 'stock' answer is about six months if everything pulled forwards and decent sized coteledons.

[quote user="macflea"]my question is once over 5 months how accurate can you get with a scanner for preg diagnosing in dairy cows?[/quote]

My direct answer to your question is - not very!

There are tables out there that do let you measure things and estimate, BUT the time spent pratting about would be better served scanning the cows sooner. In my experience those that need calving dates (dairy) get them done early and the beef boys who have an annual scanning session just want to know which are empty.

If you are new to US just make sure you check for a beating heart and be sure you know where the probe is as the bladder full of urine looks similar to a uterus full of puss and cystic ovaries can look a lot like an early pregnancy.

Re: bovine scanning

James Laidlaw — Tue, 30 Oct 2012 21:36:42 GMT

Early best as you have stated. Years ago when I used to still to LA work, we had our farmers keep a record of suspected mating dates from tail paint or other oestrus detection methods, so they had an idea of suspected foetus age. Was easy to confirm this or suggest older/younger/empty as appropriate. Others who are doing this currently and not sold out to the small animal dark side may be able to advise more appropriately though...

Re: bovine scanning

macflea — Tue, 30 Oct 2012 21:19:56 GMT

i know that feeling :(

Re: bovine scanning

james herriot lied — Tue, 30 Oct 2012 21:11:49 GMT

Once you go over about five months, they drop into the abyss and it's anybody's guess.

Not really, but I've had a few slightly off guestimates lately, so I'm a bit down on the whole thing. You most definitely do have to accept a margin of error, though.