As a measure to reduce BSE risk, 30 months and younger is the limit at which boneless beef products can be exported into the U.S. from Canada. That same 30 months-and-younger standard is also proposed for the exportation of live cattle. It's assumed that cattle under 30 months of age can't exhibit BSE symptoms. Thus, an accurate determination of age in cattle is an issue of big economic significance to the industry. In fact, discounts in the domestic market could entail carcass value losses of 30% to 50% in cattle categorized by dentition as being more than 30 months of age when, in fact, they are actually younger than 30 months.

The age determination method currently under study is dentition of each animal. Cattle are considered to be aged 30 months or older when more than two permanent incisor teeth have erupted (the first pair of permanent incisors and at least one tooth from the second pair).

Alberta Agriculture scientists recently reviewed earlier research examining the relationship between cattle age and dental eruption. The review of five different studies found it's likely that 16% to 50% of cattle categorized by dentition at harvest as being more than 30 months of age were actually younger than 30 months.

Because the five studies are more than 20 years old, the authors say it's important that the current cattle population be categorized for the relationship between age and the eruption of permanent incisors (Basarab et al. 2003. Lacombe Research Centre Newsletter, Vol. 7, Issue 4).