Horses that wind up as No. 274 did last month here in Shipshewana, near the Michigan state line, may once have carried children on their backs, pulled wagons on a farm, even been to the races. Now they are lame, aged, fractious or unwanted for any of various other reasons. Some are young, never broken in to begin with.

The slaughterhouse closings themselves may have added to the population of the unwanted. In some parts of the country, auctioneers say, the closings have contributed to a drop in the price of horses at the low end of the market, and the added distance in the shipping of horses bound for slaughter, combined with higher fuel costs, means that some small or thin horses are no longer worth the fuel it takes to transport them.

Add to that a rise in hay and grain prices, as well as a general economic slowdown.

“First time in my life I’ve seen livestock that has no value,” said Devin Mullet, owner of Kalona Sales Barn in southeastern Iowa.

After his monthly auction in October, Mr. Mullet said, he shot 28 horses that had failed to fetch any bids. Since then, he has monitored horses coming in for sale, turning away those he thinks are worthless  often yearlings and the aged, which tend to yield less meat. (Horse meat for human consumption is shipped to countries including Belgium, France, Italy and Japan.)

But opponents of horse slaughter say its domestic demise is a victory, if an incomplete one, in their fight to protect animals they see as devoted companions.