Fig. 2. Lumbar vertebra growth over time. (A) Each dot on the graph represents the length of the L4 vertebra at the time of radiography. The three breeders (02-02, 02-04 and 02-05) show increased growth of L4 over time as compared with nonbreeders and the breeding male. Starred dots indicate the L4 measurement just prior to parturition (parturition <7 days from recorded radiograph). (B) An expanded view of pregnancy 5 for Breeder 02-04 (enlarged version of the boxed area in A). Growth occurs throughout the 10-week pregnancy, ending at parturition (starred dot).