Translation:It is an expensive, but necessary investment.
The English sounds a bit off, you need a comma after expensive too. "It is expensive, but a necessary investment" just sounds better to me.
I reckon "it is an expensive but necessary investment" is a more accurate translation, but then you'd want to nix all the commas.
No, that will not be needed. Actually the comma there could be left out too.
First time I translated this without reading and without thinking into "it's an animal but necessary investment". That raised the question is there a difference between how "djur" and "dyr" are pronounced?