Lamb is generally grassfed due to the fact that sheep can get more out of a paddock of grass compared to cattle, its more cost effective. They can pratically chew to the dirt.
We dont generally have the massive feedlots that the Americans do, yet, however a good deal of cattle is certainly grain fed and nearly all of it is finished with grain to some degree. Next time you go to an sale yard or abattoir you will notice the absence of green paddocks.....
Think about the wild brahmans in outback properties, grazing and foraging away, until it comes time to muster. That process can take months, mustering, holding, transporting, selling, abatoir etc. They are not fed grass then.
For me grassfed is grassfed right up until the day it is slaughtered, and I too have been on the hunt for good quality grass fed beef myself. It seems, unfortunately, that most people offering grassfed beef think they can price their meat against woolworths and their $30 a kilo rump, where as I get my rump for $6 a kilo from Pendle Hill meat market, making grassfed beef a big investment.
I question the research methods though. There is no strict definition of grassfed to grain fed, can something be raised for 7 months on grass, 1 on grain and be called grass fed? Or even Grain fed?
Taste is not so much a barometer ofquality either, for me, one of the most important reasons of going grass (strict grass - ie visit the farm you buy it off) and not "claimed grassfed", is the omega 6 to omega3 ratio.
A friend of mine runs some cattle just outside of newcastle, he feeds grain to the calves in his backyard at newcastle, then drives them out to eat grass outside of Branxton. After about a yr, they are ready, and to do the business, he literally pulls one aside, coaxes it with Lucerne hay, and while it is munching away, Bang! - Now that is relaxed meat!
I am also looking at purchasing a whole cow from the below company, and will call him this week for pricing - he says he will do better for a full purchase and I can go and visit.
http://www.oaksorganics.com.au/The 2 biggest things in someones diet, if they are strictly paleo, that can knock this ratio into undesirable levels, is meat and nuts. Most nuts, pretty much all nuts and seeds(Macadamias and Walnuts excepted - they are perfect!) - will have an unfavourable effect on someones omega 6 levels, and Omega6:omega3 ratios, with the worst offender being almonds, no detectable omega3.
So if you keep your nut intake to 100 grams a day or so, and your meat is 100% grassfed, you will find yourself sitting pretty. Problem is purchasing it, when like I said, 6 bucks for rump. Its so cheap I make my jerky out of it, and love it.
To conclude this long post, in my opinion, any butcher bought meat will have had some contact with grain even those claiming to have been grassfed.
Incidentally, high omega 6 levels will actually dislodge omega 3 in the body. Just bad news all round.
As for Blackstump claiming grain fed is better, I have also seen this at the Meat and Wine Co,and the only thing I can put it down to is more fat content, possibly more desirable, and most people dont know any better.