"The good judges know their sheep and they usually get it right. Sometimes there is only the toss of a coin between a few at the top and it can go either way, depending on what the particular judge likes," she adds.
The pedigree flock on the farm comprise of 40-45 Vendeen breeding ewes, very carefully selected from the best breeding available on the continent with a constant eye on improvement by mating to the best blood lines available with the building of the flock under way since the late 1970s.
"I went to NI in 1979 and bought a ram for to run with the commercials we had at that time. I was so pleased with him that I went back to the North again and I bought three ewes and a ram before I went to Carlisle and bought a good few ewes there," she explains.
The commercial flock on the farm was quite sizeable in the earlier years and was largely Texel, so what was it about the Vendeen that became so attractive?
"Once I bought the first of them, I liked the Vendeen because they are very quiet, nice and long and very easily fleshed - that was what I liked about them from the beginning - easily finished and good to grade. That was why I bought into the pedigree I was so pleased with the commercials," she says.
Cheryl has visited France a good few times purchasing some of the best ewes and rams to be found. For the last 7-8 years she has been using AI from French rams.
"I go to the AI centre in France, see the rams and I bring in what I like," she explains.
However, conception rates to AI are proving to be widely variable.
"The AI is very much hit and miss, I find, and conception rates vary widely. A good year 60pc can be got, and another time it may be back as low as 20pc.
"Last year I got 30pc and the year before it was 60pc - don't ask me why because there is no knowing of why the variation is so wide because the ewes can be in the very same condition and the results very different, but I have stayed with it for the last 7-8 years," she says.
"Vendeen are naturally an early breed and we lamb in December and into early January, while in France they lamb in October and November. We feed as normal for the Easter trade or later.
"The better rams are all kept for breeding and the ewes the same. Some of the better ones are kept on the farm and I have a steady market from customers for the others - a lot of regular customers. The rest will be sold to the factories," she says.
"Originally I had a ram Leehall Keats imported from the UK that produced some excellent progeny - he did very well for me and I had fantastic lambs. Then I brought in brought in two very good rams. Rivalin bred lovely females and Challoo was a great meat ram. They were top of the range rams in my pedigree flock," she adds.
She won the Vendeen Flock of the Year first in 1997, won her second award in 2004 and nine years elapsed before the third success.
"It is not easy won. There are a lot of contenders. I usually go to the same shows each year but some years are more successful than others. That is the way it goes," she says.
Repeating her success of 2013 by retaining the award in 2014 was a rare enough achievement but making it three-in-a-row by adding the award for 2015 was a 'dream' result because "it is so difficult to do" that it was never before achieved.
With her husband, Conor, she shares a lot of interest in the breeding in their Simmental suckler herd and is very concerned that the pressure on participants in the BDGP to meet qualifying standards on the index of breeding stock "could destroy" the suckler breeding.
"I have seen what happened in sheep breeding with 'stars' which did not work and sheep farmers are not being incentivised any more and we are getting on with breeding the best with the best," she says.
"About three years ago I had the first five in the (sheep) class and they looked five star but they only had three star because they were all French breeding. If the reliability figures are not good enough it does not matter what stars they have.
"It is not being impressed on farmers enough how important the reliability figures are and farmers don't understand that.
"The star rating really has not worked in the sheep and it is going to be very interesting what happens with the cattle," says Cheryl.
"I saw it all happening in the sheep when the breeders had to have them and were paid to have them but it is all gone and we are back to being more normal again which makes a lot more sense.
"I don't think there is enough research done and it is almost impossible to get figures on the imports," she adds.
Top 10 Vendeen Show Flocks of the Year 2015
1 Cheryl O'Brien, Cork.
2 Gordon and Yvonne Johnston, Westmeath
3 Ciaran Coughlan, Offaly
4 Ena Nagle, Cork
5 John Lynch, Longford
6 Joey Walsh, Kildare
7 Anthony and Oisin Gannon, Offaly
8 Shay Kennedy, Waterford
9 Padraig Monaghan, Mayo
10 John Dolan, Offaly