On December 23, 2003, Agriculture Secretary Ann M. Veneman announced that the U.S. Department of Agriculture (USDA) had diagnosed a presumptive positive case of bovine spongiform encephalopathy (BSE) in an adult Holstein cow in the state of Washington. Following confirmation of the preliminary diagnosis (Dec-25-2003), Secretary Venemen announced (Dec-30-2003) that USDA’s Food Safety and Inspection Service (FSIS) would further strengthen U.S. protection systems designed to safeguard the nation’s consumers against BSE and listed six specific actions that would be employed to protect public health. One of the six action points cited by Secretary Venemen focused on control of “Specified Risk Material” (SRM) and included the following directive:
“Effective immediately, upon publication in the Federal Register, USDA will enhance its regulations by declaring as specified risk materials, skull, brain, trigeminal ganglia, eyes, vertebral column, spinal cord and dorsal root ganglia of cattle over 30 months of age and the small intestine of cattle of all ages, thus prohibiting their use in the human food supply. Tonsils from all cattle are already considered inedible and therefore do not enter the food supply…”
The directive quoted above was among four new regulations publicly released by USDA on January 8, 2004 and subsequently implemented in an FSIS Interim Final Rule (9 CFR Parts 310, 311, 318, and 319) published in the Federal Register (Vol. 69, No. 7, pp. 1862-1874) on January 12, 2004.
Because most of the SRM control measures outlined in the new regulations were required only if the listed tissues were obtained from cattle 30 months of age or older, it was necessary for FSIS to specify methodology that would be used by inspection program personnel to determine cattle age at harvest. According to the Interim Final Rule, FSIS personnel are permitted to use a combination of two methods to verify the age of cattle presented for harvest in federally inspected beef plants. If “accurate and reliable” records documenting the actual age of an animal are presented at the time of harvest (i.e., a birth certificate, cattle passport, or other form of identification and age documentation), FSIS inspectors may accept such records as verification of the animal’s age. If no such information is available, or if the records presented to document the age of an animal are of questionable validity, then the age of the animal is verified using dental examination (dentition). Moreover, the Interim Final Rule specified that, if dentition is used as the basis for age verification, cattle are considered to be 30 months of age or older if they have at least one of the second set of permanent incisors erupted (a tooth is “erupted” if it protrudes above the gum line).
Another common question, posed by many in the beef industry, was whether, in the absence of actual age documentation, USDA carcass maturity classification (specifically skeletal maturity, assessed immediately following splitting of the carcass) could be used, rather than dentition, for identification of cattle that are 30 months of age or older. For decades, the Meat Grading and Certification Branch of the USDA-AMS-Livestock and Seed Program has used beef carcass indicators of age or physiological maturity (skeletal ossification, shape and color of the rib bones, and color and texture of lean tissue) to reflect age/maturity differences – primarily for purposes of grading and marketing. The youngest maturity classification for beef carcasses, A-maturity, is generally believed to approximate a chronological age range of 9 to 30 months, so, in theory, cattle producing A-maturity carcasses should be less than 30 months old. In a study involving commercially fed cattle of unknown ages, Lawrence et al. (2001) found little agreement between dentition and carcass maturity classification. However, there have been no direct comparisons of the efficacy of dentition vs. carcass maturity for identifying actual age differences among cattle currently comprising the U.S. fed beef population.
The stated objectives for this work were:
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