US cattle herd at 61-year low, but rebuilding may be under way

* USDA cattle herd down about 1.6 pct yr-over-yr * Cattle herd remains lowest in 61 years * Ranchers begin retaining breeding stock * Record high beef prices seen through 2014 By Theopolis Waters CHICAGO, Feb 1 (Reuters) - The U.S. cattle herd shrunk for a sixth straight in 2012 due to high feed costs tied to drought and that should mean consumers will continue paying record high prices for beef. The U.S. Department of Agriculture on Friday said the U.S. cattle herd as J