http://revach.net/article.php?id=5146

Section: Parshas HaShavua   Category: Life Lessons
Parshas Ki Seitzei: Rav Chaim Kanievsky on the Treatment of Animals

The Torah writes the parsha of Malkos right next to the parsha of not muzzling your animal while it works. Chazal learn from here halachos of when to give Malkos. "Yet, on a very simple level," says Rav Chaim Kanievksy, "there is a valuable lesson to be learned here.

When it comes to giving Malkos, Bais Din must be very careful not to give more Malkos than he deserves. Similarly, even though animals were made to benefit mankind, and it is permissible to use an animal to do hard work, nevertheless it is forbidden to cause him one drop more of pain than necessary."