Horse
In Ezekiel 26:11, this signifies the love of learning or intellectual things. (Arcana Coelestia 3727)
In Revelation 6:2, this signifies the love of understanding the Word. (Apocalypse Revealed 298)
In Zechariah 12:4, this signifies that the intellectual should be filled with falsities. (Arcana Coelestia 2383[2])
In general, 'a horse' signifies knowledge or understanding of the Word. In an opposite sense it signifies the understanding of the Word falsified by reasonings, and likewise destroyed from self-derived intelligence. 'A dead horse' signifies no understanding of truth from the Word.
Jeremiah 4:7-8
7
The lion is come up from his thicket, and the destroyer of the Gentiles is on his way; he is gone forth from his place to make thy land desolate; and thy cities shall be laid waste, without an inhabitant.
8
For this gird you with sackcloth, lament and howl: for the fierce anger of the LORD is not turned back from us.