(some claim that this work was not authored by Schweitzer as it does not appear in his writings. I think that those librarians are too fussy. I choose to believe. Here is one much shorter by him that is considered authentic)

O, heavenly Father, protect and bless all things that have breath;
guard them from all evil,
and let them sleep in peace

A Prayer for Animals

Hear our humble prayer, O God, for our friends the animals,
especially for animals who are suffering;
for animals that are overworked, underfed and cruelly treated;
for all wistful creatures in captivity that beat their wings against bars;
for any that are hunted or lost or deserted or frightened or hungry;
for all that must be put death.
We entreat for them all Thy mercy and pity,
and for those who deal with them we ask a heart of compassion
and gentle hands and kindly words.
Make us, ourselves, to be true friends to animals,
and so to share the blessings of the merciful.