Every now and then, there is another source claiming that a cheaper version of a specific feed is as good as the more expensive one. I only need to bring up here the example of piglet feeds, but the same can be said for any other similar product, like a broiler pre-starter, or a calf milk replacer, and so on. The dilemma is obvious, I presume, as a cheaper feed that works as good as a more expensive one means more money left for the animal producer.
However, let me disagree by saying that a cheaper feed or an expensive feed is not always the right feed to use. To use the piglet example from above, it suffices to say that healthy pigs require but few specialty ingredients in their feeds to thrive. Thus, their feed can be inexpensive without sacrificing their performance or health. The same feed given to pigs of average health will probably deprive them of the chances to maximize their performance. And, when such cheap feed devoid of essential specialty ingredients is offered to pigs of below-average health status, then performance and health will be compromised.
In essence, there is no single feed, expensive or otherwise, that can be used in all circumstances. When saving on feed cost, we must ensure that reduced animal performance and impaired health will not deprive us from these savings. On the other hand, there is no reason why expensive feeds should be offered to animals when these animals do not require such an over-fortified nutrition plane.
So, instead of spending research resources trying to support expensive or cheap feeds, I believe it would be wiser to spend such money and effort identifying under what conditions each feed should be used. To this end, I would highly recommend to all readers to look up research conducted by Kansas State University, where considerable work has already been done towards this direction.