A lot is the thing that actually crosses the auction block. It bundles animals of the same species and sex class so the auctioneer can sell them as one unit to one buyer.
Each lot carries:
a lot number (unique within the sale) and a ring order that sets when it sells,
a head count and, when animals are weighed together, an aggregate weight,
a pricing mode — how the bid is quoted.
The three pricing modes are:
Per CWT — price per hundredweight; the buyer's bid is multiplied by total weight.
Per head — a flat price for each animal.
Lump sum — one price for the whole lot.
A lot can pull animals from more than one consignment (a "cross-consignment" lot). When it sells, the proceeds are still traced back to each animal's original consignor for settlement.