For horses. The existence of horses in Egypt proves that the Joseph narrative may not be dated earlier than the Hyksos period, since the horse was unknown there until the Hyksos introduced it (see on ch. 41:43).
For that year. It is not certain which of the seven years of famine is here meant.
Some commentators think that the distribution of seed to farmers the following year (v. 23) shows that that was the seventh year of the famine, and the year in which the cattle were exchanged for food consequently the sixth year. However, it is probable that some planting had been carried on during all the years of famine in fields bordering on the Nile, which would render the reference to seed in vs. 23, 24 of no value as evidence that the last year is here meant. Nevertheless, the year referred to in v. 17 probably fell in the latter part of the period of famine.