Here is one source of information:
http://www.ces.uga.edu/Agriculture/agecon/pubs/AGECON%2011-002.pdf
Holding Period
The period of time that a breeding animal is held by the taxpayer determines whether a gain in excess
of recapture of depreciation (capital gain) on the sale or other disposition will be treated as a short-term
gain or a long-term gain. The holding period which must be exceeded for a gain to be considered a
long-term gain is 12 months for hogs, and 24 months for all other livestock.
“Quick Reference” for Livestock Sales Reporting
Category ******* Rules ******* Where Reported
Livestock held in the ordinary course of business (Market Livestock) *** Not § 1231 property, subject to S/E tax *** Schedule F (Form 1040)
Livestock held for breeding, but holding period not met *** Not § 1231 property, not subject to S/E tax *** Form 4797 Part II
Livestock held for breeding, holding period is met *** § 1231 property, not subject to S/E tax
a. Raised animals and purchased animals sold at a loss *** No depreciation *** recapture Form 4797 Part I
b. Purchased animals sold at a gain *** Subject to depreciation recapture
and unrecaptured § 1231 loss rules ***Form 4797 Part III