The number was 1,697 yesterday, and to that, 944 cows from Miyagi Prefecture alone were added overnight, bringing the total to at least 2,641.
Tokyo Shinbun, citing Kyodo News (7/23/2011):
Miyagi Prefecture announced on July 23 that additional 944 meat cows from Miyagi Prefecture suspected of being fed with rice hay collected after the Fukushima I Nuke Plant accident had been shipped to 6 prefectures - Tokyo, Yamagata, Miyagi, Kanagawa, Chiba and Niigata. The total number of potentially contaminated cows shipped from Miyagi is now 1,183.
According to Miyagi Prefecture, radioactive cesium exceeding the provisional safety limit for the feed [300 becquerels/kg] was found from the rice hay kept at 17 cattle farms. Total 626 cows had been shipped from 16 of those farms.
In addition, 318 cows had been shipped from 15 cattle farms whose rice hay wasn't tested because it was all used up. The prefectural government decided it is highly possible that the rice hay fed to the cows was contaminated with cesium.
Miyagi Prefecture has the detailed test results (in Japanese) on its website. The highest radioactive cesium level from the most recent test was 7,822 becquerels/kg in Shiroshi City, located near the prefectural border to Fukushima near the cities that have been found with high radiation areas (Date City, Fukushima City, etc.).