Few would suggest it's easy tracking an unidentified animal from the packinghouse door back to the ranch of origin. But no one seems to know precisely how difficult it is, either.

We queried several industry players — those whom you'd figure would know — but they either demurred or admitted there's no way to know how many cattle today can be traced back for the purposes of animal health or commerce.

From the standpoint of the Animal and Plant Health Inspection Services, Amy Spillman, USDA public affairs, explains that all adult cattle are supposed to have official USDA back-tags at slaughter. These tags identify the most recent pre-harvest location of cattle. But, she adds, fewer than 25% of these back-tagged animals going through federally inspected harvest facilities have brucellosis vaccination ear tags that would allow quick trace-back to the ranch of origin. Spillman estimates about half of all dairy cattle are currently identified through the Dairy Herd Improvement Association.

USDA can track unidentified cattle, it just can't track them all. And, often, they can't do it within 48 hours as the National Animal Identification System (NAIS) proposes.

As an example, a couple of years back, out of all the carcasses USDA was tracing back due to residue concerns, the agency traced back all but 16%. Often, that entailed trouncing through lots of receipts and checking accounts in order to do so.

Finding 84% is either mighty good or the equivalent of Russian roulette. Either way, it's not USDA's fault; it's the ID system they've been dealt.

According to the last beef report by the National Animal Health Monitoring Service in 1997, 48.1% of all beef cow operations were estimated to use some form of individual ID on calves. Another 53.2% were using individual ID on cows. Keep in mind that's operations. The percentage of calves and cows identified individually by some means was estimated at 64.7% and 69.8%, respectively.

One could assume the majority of the 2.4 million head marketed through programs listed in the latest BEEF Alliance Yellow Pages (August 2004 issue) would be more traceable. Certainly, within some of the programs, cattle are traceable from the box back to the ranch of origin. Even if you figure all listed were that traceable, though, that's only about 10% of that year's fed cattle harvest. And, really, it's the cows entering the marketplace that have the greatest opportunity to harbor long-incubating disease such as BSE or Johne's.

So, there are facts here and there, but most of the estimating is just that. Hopefully, NAIS will change that.