Normal profiles for deciduous dental eruption in domestic piglets: effect of sow, litter, and piglet characteristics.

摘要

The deciduous dentition of the domestic pig is comprised of 28 teeth (2 x incisors 3/3, canine 1/1, premolars 3/3, molars 0/0). The timing and sequence of deciduous dental eruption were determined from oral exams on 233 Yorkshire piglets from 0 to 5 wk of age. Eruption occurred sooner in gilts for all molariform premolars (p(3), p(4), and p(4), P < 0.01) and first incisor, i(1) (P = 0.004). Birth weight influenced eruption for all teeth except i(1) (i(1), p(3), p(3), p(4), and p(4); P < 0.01), with heavier piglets having earlier eruption. Average daily gain in wk 1 of life was associated with earlier eruption times of p(3) (P = 0.006), p(4) (P = 0.001), and i(1) (P = 0.001), whereas ADG during wk 2 was associated with earlier eruption for p(4) (P = 0.036). The parity (P = 0.025) and age (P = 0.013) of the sow were associated with earlier eruption of i(1). No litter characteristics were found to be significant. Sequence of eruption was determined to be i(1), p(3), p(4), i(1), p(3), p(4), although polymorphisms (reversals) were found to occur in over 40% of individuals of both sexes for mandibular i(1) and p(4) and maxillary p(3) and i(1). Size of the left i(3), which is already erupted at birth as part of the needle teeth dentition, was found to be larger in males (P = 0.026). Body weight gain was not associated with the size of i(3). Eruption times of p(3) and p(4) (the first premolars to erupt) occurred later than previously reported in the literature. Because these teeth are associated with initiation of feeding behavior for miniature breeds, implications of molar eruption on feeding behavior and feed intake should be considered.