There is no question but these trends will have a negative effect on the meat sector, says Michael.
He pointed out the importance of carcase confirmation score was confirmed by the Grange carcase study where a two unit increase in confirmation score increased meat yield by 7 percentage units and carcase value by 11.6pc.
High quality carcasses from the suckler herd are under-priced, he argues. Based on the meat yield the differential between the O3 and the U3 carcasses, or the standard Friesian animal and the good continentals from the suckler herd, should be about 45c/kg which would mirror the UK.
The average varied in the UK last year but the price differential was about 45c/kg. He stresses he isn't talking about the actual price but the grade differential.
"Ours is less than 30c/kg, theirs is averaging about 45c/kg between O and U grades," he says. "In Italy the price for very good confirmation animals is very high - the difference was high there at 96c/kg," says Michael who retired from Teagasc Grange in 2009 after joining the organisation in the 1960s.
"My argument is that the factories want the good animals and they want them to be based on meat yield and the only way they can get the message across to farmers is through price - whether my 45c/kg should be 42c/kg or 48c/kg is not the issue; it should be in that region.
"Based on the other countries it is probably greater than the 45c/kg I'm talking about."
He pointed out those delivering good quality young bulls, with many coming in at U grade, were often losing heart.
"I know the factories will argue a lot are going to the UK market rather than the Italian market and the price differential isn't as significant, but the price differential in the UK is around what I think it should be," he says.
"People producing the really good U animals are nearly asking at this stage is there any point in going that far? When I started talking about the [QPS] to the factories they agreed 100pc, but argued that the proportion of good young bulls around was too small to allow them to pay the differential.
"They claimed the same scarcity applied to Us and high quality carcases. But this changed from 1980 for the next 20 or 25 years and the number of continentals increased so they were getting more of those too. So definitely they are in a better position now in relation to both U grade steers and bulls."
He also stresses that the beef carcase classification scheme or grid should not be part of the Bord Bia quality assurance scheme. "It shouldn't be part of it, it is an entity of its own," he says. "The grid should be separate - farmers start talking about it not being suitable and then the grid not being suitable. The grid has nothing to do with that [Bord Bia QA]. It just has to do with meat yield of animals.
"It is not a direct measure like fat in milk. The estimate is based on carcase confirmation scores and fat scores is an accurate indicator of meat yield."
He points out breed societies have very successfully promoted the Hereford and Angus breeds yet there was little difference in meat eating quality between those breeds and the continentals.
Michael also has concerns over the age restrictions being placed on young bulls and feels there is a lot of emphasis being put on carcase weights with the much-publicised ending of the moratorium that saw factories move to penalise those weighing over 420kg.
"If the trade says that it has to be less than a certain weight where they are selling the animals then who am I to question it.
"Charolais and late maturing continental breeds [Simmental, Limousin, Blonde d'Aquitaine] have gone up and up and up. Now with restrictions on carcase weights farmers feel like they have to move away from the larger continentals which is a mistake," he says, pointing out if farmers were getting the correct differential payment for the higher grades then they wouldn't be under pressure to produce the animals to heavier weights to make a profit.
"You can produce lighter carcases from them by better feeding and getting rid of animals at an earlier stage. I think if we start moving into smaller carcases it might be right for the British market we are supplying with nearly 50pc going to Britain.
"However, with the pound going down in value Britain may not be as attractive and Britain was generally associated with the smaller breeds and lighter carcases.
"People will be more interested in going to our own currency markets like Italy and where the animals that fetch the top prices are the large continental breeds. They will say they don't want heavy carcases either but if you feed them better and slaughter them younger you'll deliver the lighter carcases."
He warns against any drive away from meat yield, pointing to the knock-on impact on our carbon footprint as a cow will still be producing the same level of gases. "If you are talking about greenhouse gases, if you are getting an average carcase weight for steers and bulls of 400kg rather than a 320kg carcase - it is the same impact in terms of output per animal."
However, he acknowledges killing young bulls at an earlier slaughter age is the right way to go from an efficiency point of view. "All of Continental Europe is young bulls and 50pc of our beef is going to Continental Europe," he said. "Young bulls and lean meat and efficiency all go together. Beef from dairy crosses is definitely less efficient."
He says the dairy animals eat more and grow more slowly, with up to 50pc difference in efficiency of energy-to-meat. However, he acknowledges that their status as a by-product of the dairy herd does confer some advantage.
For the suckler herd, he feels the ideal situation is using a crossbred cow for hybrid vigour with a late maturing continental as a terminal sire. However, he says many herds were too small for that, while AI was not as easy for smaller and part-time herds.
Cheap beef imports to the UK are far from a done deal
Quality controls may reduce the attractiveness of the much speculated possibility of the UK sourcing more cheaper beef from the likes of Brazil or the US, says Michael Drennan.
He believes that the fact that Brazilian and US producers use hormones that are banned throughout the EU could be crucial.
"I don't think that will be changed so that will be a potential restriction," he said, emphasising we are still in the realm of speculation.
"If sterling stays low it will be in the meat factories' interest to get more product into other EU countries, all things being equal. There is no question about it but Ireland has benefited from membership of the EU," says the researcher who studied in the University of California, Davis in the 1960s before going on to carry out a PhD into cattle research in Trinity College in the 1970s.
Throughout his years in Grange, Teagasc carried out some very innovative research including work in the 1970s on the effects of growth hormones, before they were banned from use.
Michael points out advice and research is in a constant state of flux and products in use now for humans and animals may well be banned at some point in the future.