First they said the rice hay was fed to the cows because there was nothing else to feed due to supply disruption after the March 11 earthquake. Then it turned out that rice hay was integral part of fattening the meat cows before they were sold to the market.
Then the news broke on August 19 that some meat cows from Fukushima were highly radioactive even without radioactive rice hay.
And then it turns out that 4,000 such cows may have been shipped since the accident by one cattle farmer who owns cattle farms in Namie-machi and in two other towns (Tamura City and Katsurao-mura). The radiation level on the farm in Namie is very high, as you can read in the Kahoku Shinpo article below.
Well, that instantly doubles the number of meat cows potentially contaminated with radioactive cesium. I say potentially, because most of the meat has been consumed already and there's no way to test it.
From Kahoku Shinpo, local Fukushima paper (8/21/2011):
福島県浪江町の農場から出荷された肉牛４頭の肉から国の暫定基準値（１キログラム当たり５００ベクレル）を超える放射性セシウムが検出された問題で、福島県は２０日、同じ農場の牛５頭の肉も基準値を超えていたことを明らかにした。浪江町の農場からは、福島第１原発事故後の３月１５日～４月１９日、汚染された９頭を含め計２２９頭が横浜市に出荷されていた。
Regarding the 4 meat cows from a cattle farm in Namie-machi in Fukushima Prefecture that exceeded the provisional safety limit for radioactive cesium (500 becquerels/kg), the Fukushima prefectural government disclosed on August 5 that the meat from 5 additional cows from the same farm contained radioactive cesium exceeding the provisional safety limit. From this farm in Namie-machi, total 229 cows including the 9 that were contaminated were shipped to Yokohama City between March 15 and April 19.
また、この農場を所有している福島県葛尾村の農家は田村市と葛尾村にも農場を所有し、３カ所で飼育していた約４０００頭の牛が、原発事故後に出荷されていたことも分かった。
The farmer who owns this cattle farm in Namie-machi also owns farms in Tamura City and Katsurao-mura, and total 4,000 cows in his three farms were shipped after the Fukushima nuclear accident.
県の説明によると、５頭からは肉１キログラム当たり５９３～７８６ベクレルが検出された。最初の４頭は５１３～９９７ベクレルで、ほぼ同じレベルの汚染状況だった。
From the 5 cows, 593 to 786 becquerels/kg of radioactive cesium has been detected. The first 4 cows tested 513 to 997 becquerels/kg. The contamination level is similar.
セシウム汚染を受けて、県畜産課は１９、２０日、農場３カ所を調査した。浪江町の牛舎の入り口で最大毎時１５マイクロシーベルト、屋外の雑草からも３５マイクロシーベルトと高い放射線量が確認された。牛舎内の餌の台からも最大５．５マイクロシーベルトが計測された。
Upon the news of radioactive contamination, the cattle farming section of the Fukushima prefectural government investigated the three farms on August 19 and 20. At the farm in Namie-machi, the entrance to the barn measured 15 microsieverts/hour maximum; 35 microsieverts/hour radiation was detected from the grass growing outside, and 5.5 microsieverts/hour radiation at the feed trough in the barn.
葛尾村でも牛舎内や周囲の雑草の放射線量を測定したほか、乾燥干し草の保管場所を確認した。放射線量は地上１メートルで毎時０．５～０．８マイクロシーベルトだった。田村市では牛舎入り口付近の高さ１メートルで０．３マイクロシーベルトだったという。
At the farm in Katsurao-mura, they measured inside the barn and on the grass outside, and the storage facility for the dried hay. The air radiation level 1 meter off the ground was between 0.5 to 0.8 microsievert/hour. At the farm in Tamura City, the air radiation level 1 meter off the ground near the entrance to the barn was 0.3 microsievert/hour.
県の調査に対し、農家は稲わらではなく輸入した干し草などを与えていたと答えており、セシウムに汚染された原因はまだ分からない。ただ、牛は土をなめてミネラルを補給する習性があり、放射線量が高かった時期に、雑草を食べたりしなかったかどうかなどを引き続き調べる。
The farmer says he fed the cows with imported hay, not the rice hay. The cause for cesium contamination is not yet known. However, cows lick the dirt to obtain minerals. They may also have eaten the grass outside when the radiation level was higher.
浪江町の農場のある地域は４月２２日、福島第１原発事故によって計画的避難区域に指定されたが、汚染された牛は指定前に出荷されていた。指定後の４月２８日、農家が葛尾村と田村市の農場の牛を出荷する際、県はそれぞれ１頭の肉の放射線量を測定したが、約６０～９０ベクレルと基準値を下回っていたという。
The farm in Namie-machi is located in the "planned evacuation zone" designated on April 22, but the contaminated cows had already been shipped by then. Fukushima Prefecture measured one cow each from the farms in Katsurao-mura and Tamura City on April 28 when the farmer shipped the cows, but radioactive cesium was detected at only 60 to 90 becquerels/kg, below the provisional safety limit.
農家は既に県外に避難、農場は休止状態になっていて牛はいない。
政府は１９日、福島県内の肉牛の出荷停止を解除する予定だったが、セシウム汚染が発覚し、解除を見送った。
The farmer has already evacuated outside Fukushima, and there is no cow left in the farms. The national government was going to lift the shipping ban on the meat cows in Fukushima Prefecture, but it decided not to when the radioactive cesium contamination [without radioactive rice hay] was discovered.
Before the Fukushima accident, the amount of radioactive cesium in beef in Fukushima was max 0.055 becquerel/kg. In the post-Fukushima Japan, over 9,000 times the pre-Fukushima level of radioactive cesium has to be considered "safe". (Data on radioactive cesium in Fukushima beef from Japan Chemical Analysis Center database, in Japanese.)
Namie-machi and Kazurao-mura have been designated as "planned evacuation zone". Part of Tamura City has been designated as "evacuation-ready zone". The national government still plans to "revise" these designations and return the residents, as Fukushima I Nuclear Power Plant is now "stable".
15 microsieverts/hour radiation would result in the annual cumulative radiation exposure of 131 millisieverts, and that's external radiation only.
Poor cows. After having been fattened up to the max for sale, suffering high cholesterol and high blood pressure, they had to be zapped by radiation...