The German Tierschutzgesetz IS inadequate on this regard. This has been discussed in Germany on the behalf of various other similar cases ("Knut", anyone?) before, without any useful outcome. Sometimes, like in this case, national and international (German vs EU, zoo vs. animal right etc.) regulations collide, making it almost impossible to follow one law without violating another.
In Switzerland or Denmark, the national legal system allows zoos more freedom in their decision on this behalf. Surplus animals can be euthanized if no apt husbandry to place them into can be found. However, the media there will still try to create turmoil when a popular species is involved-see the hippo discussion at Basle.
For those who might not know otherwise and think that the Madgeburg Zoo staff went rogue: the decision to euthanize the tiger cubs in question was undertaken on orders of the studbook coordinator. IF you're looking for a scapegoat, blame him/her-or Henning Wiesner, who in his time as director of the Hellabrunn zoo reacted snooty and stubborn when some people (who happen to know their stuff) pointed out to him that the subspecies origin of the very tiger causing all this mess was somehow fishy, and insisted on breeding with the animal.
The Madgeburg Zoo clearly didn't jump the gun on the situation, but assembled a factual commission first and contacted the local state veterinarian. More can be read on the public explaination published by the zoo:
ZOO-MAGDEBURG
Do ask if you need any help with the translation.
"To be perfectly honest, I don't really see why Magdeburg couldn't keep these animals for display only and continue breeding when they were dead or moved on to another collection".
Then I would like to ask you, in all honesty, to climb down from your ivory tower and assemble a fully equipped, well-managed and financially sustainable exotic animal rescue center network that could keep tigers and other exotics legally and appropriately, especially in accordance with German law... There is a serious lack of such institutions all over Europe, and so far hardly anything has come up other than people trying to tell zoos what they should do and what not, but without offering any realistic alternative or (financial) support.
"IMO it's rather impossible (or at least VERY hard) to clearly and objectively state when zoo animals can be killed and when not. There's no real definition of the word "surplus" possible..."
I think there are various situations where it is pretty clear when a zoo animal can be killed; I even mentioned some already (to avoid uncurable disease/suffering, to prevent an epidemic spread...). Additionally, I also think that there are pretty clear situations in which a zoo animal is surplus: when the zoo cannot offer any short/long-term adequate solution of keeping the animal appropriately and when no adequate alternative husbandry can be found. Or do you think it would be better if the tigers had ended up in some inadequate makeshift cages behind the scenes or, to provide more grist for the anti-zoo lobby mill, had been given to some shady animal trader and had been sent off to China?
Funny enough, several German zoos like Nuremberg or Hellabrunn kill part of their surplus zoo livestock(sic!) every year to feed the whole carcasses to their carnivores (a recommendable thing to do, if you ask me). But since these are "only" herbivores such as sasin or axis deer, hardly anyone rallies against this (thank goodness). But once "holy" animals such as tigers or hippos are involved, everyone goes bonkers...Speciesism in its purest form.
