Contradiction with Proverbs 12:10
This verse states that a righteous man regards the life of his beast, which might contradict with the amount of labor placed on the animals in Genesis 24:20.
Proverbs 12:10: A righteous [man] regardeth the life of his beast: but the tender mercies of the wicked [are] cruel. [tender...: or, bowels]
Contradiction with Exodus 20:8-10
These verses command rest on the Sabbath for all, including animals, which contrasts with the urgency and labor in Genesis 24:20.
Exodus 20:8-10: Remember the sabbath day, to keep it holy.
Contradiction with Deuteronomy 25:4
This verse commands not to muzzle an ox when it treads the grain, suggesting considerate treatment of working animals, which can be seen in contrast to the exhaustive effort made by the servant in Genesis 24:20.
Deuteronomy 25:4: Thou shalt not muzzle the ox when he treadeth out [the corn]. [treadeth...: Heb. thresheth]