Translation:

21. And in cattle (too) ye have an instructive example: from within their bodies We produce (milk) for you to drink; there are in them (besides) numerous (other) benefits for you; and of their (meat) ye eat;

Notes (Tafseer)

2881. 'Ibrat. the root meaning of the verb is "to interpret, or expound, or instruct", as in xii. 43; the noun means, an interpretation, or example or Sign that instructs, as here and in xvi. 66, or gives warning, as in iii. 13. From cattle we get milk and meat; also from their skins we make leather for shoes, boots, straps, saddlery, and numerous other uses; from camel's hair and sheep's wool we weave cloth, hangings, carpets, etc.; from the horns of cattle we make cups and articles of ornament or use; and camels, horses, donkeys, mules, etc., are used for riding, carrying loads, or drawing vehicles.