Evening all,
I posted this elsewher this evening, I was asked my thoughts on the Pre Alpin Testudo tortoise diets that I have been using this year and I thought I'd like to share it with you (reasonable) people.
My interest in the Pre Alpin Testudo products started about four years ago via a "discussion" between Andy Highfield and Ed Pirog on the old Tortoise Trust Yahoo group. In 2006 I read Holger Vetters book on Hermanns tortoises and again, Pre Alpin was mentioned.
I became interested in the annual feeding cycles of Hermanns tortoises. The spring glut, the dry summer, the autumn plant regrowth. I noticed that my tortoises would happily forage on dried summer plants in their enclosure. Then I read Wolfgang Wegehaute’s book on Hermanns tortoises which spoke of an annual cycle and the feeding of dried plants for periods of the summer.
I've spent a couple of years allowing the outdoor enclosures to dry out and collecting dried weeds as well as preparing some of my own from fresh weeds collected in the spring. I also began adding chopped redigrass to my feeds.
I finally got hold of some Pre Alpin Testudo in March, around the time the tortoises exited hibernation. Initially I used small amounts mixed with the main diet, this was readily accepted by my Hermann’s. Come summer, I was offering Pre Alpin Testudo products as a main meal both pre soaked cobs and the dried "fibre" product. I continued to offer it right up until the tortoises entered hibernation.
I've used it as my "dry summer feed", if the product is allowed to dehydrate again, the tortoises continue to eat it. It becomes a closer replication of the dry plant, lower water content. (I like my tortoises to drink from a bowl for their water intake by the way).I also hydrates the cobs using boiling water so that a lot of the moisture evaporates away before feeding. So, I had another dry feed along with the wild plants. Since people have cottoned on to this product , its been put forward as a supplemental winter feed which is good but not why I'm using it. I want that summer feeding replication.
The pre alpin site itself explains the thinking behind the products, the Andy Highfield article
http://www.tortoisetrust.org/articles/dietaryfibre.htmlalong with the two Herrmann’s tortoise books mentioned above fill in some of the gaps.
There is a passage on the summer conditions for Hermann’s tortoises here, from Wolfgang Wegehaute
http://www.testudo-farm.de/html/life_in_the_wild.htmlThere are 3 (four if you count the “baby” product) Pre Alpin Testudo products explained here.
http://www.agrobs.de/en/products/Tortoises.htmlI've seen some concerns voiced that the nature of this product is effectively "malnourishing" a tortoise. It is something I considered myself and as a result only use it alone during the high summer period. I recall reading years ago that someone worked out that the calorie requirement of an adult Med tortoise was something like 10 calories (I've mislaid the book in question but it was around the 10-15 calorie mark) so I don't think its likely a tortoise will starve on this diet. Although the product has an accepable Ca:P ratio of 2:1 I tend to treat it as I do other feeder plants and add supplementation as required.
Although I've only recently started using these products I can be sure that it has in no way inhibited the growth of my tortoises who have continued to gain weight and SCL as rates equal to previous years. Shell growth has been good and smooth but, it usually is.

I have two one year old T Hermanni Hermanni that have become the test bed for this product for me. They have been fed Pre Alpin since day one of my having them (aged one year), their growth has been good this year but I'm using every trick in the environment/hydration/feeding book to ensure this is the case.
One last thing and a point I think is important and often overlooked in animal care...poo.
On their old diet my tortoises never had loose faeces, now its unreal. If you've experienced a tortoise defecating in its bath and, if left, the stool disintegrates. Well if mine poo in the bath, it comes out in a solid, bound package and bobs around like a cork and does not disintegrate in contact with water. You might say that if it comes out like it's gone in what’s been taken out by the tortoise but as I said before, no obvious impact on growth so far.
Heres some lovely pictures.....

Basic Pre Alpin Testudo cob

The same cob, hydrated

Pre Alpin Testudo Fibre

Poo

More poo.