10 Malas a Day...
...keep the lower realms away!
One simple way to be constantly benefiting animals is to do mantras to purify your body so that wherever you go, beings in your vicinity are blessed:
“..when a person who has recited ten malas of Om Mani Padme Hum a day goes into a river or an ocean, the water that touches that person’s body gets blessed, and this blessed water purifies all the billions and billions of sentient beings in the water. So it’s unbelievably beneficial.” 
Kyabje Thubten Zopa Rinpoche