Occurrence and inheritance of wattles and effects of genotype at wattle locus on Gompertz growth curve parameters in "Nero di Parma" pigs

The occurrence of wattles, the inheritance model of the trait and the effects of wattle genotype on Gompertz growth parameters for weight and some body measures were evaluated in “Nero di Parma” swine population. To these aims, the complete database of “Nero di Parma” pig, containing the parentage and morphologic description of 4031 pigs born between 1998 and 2009 was used: of them, 68.3% showed no wattles, 3.2% one and 28.5% two wattles. The wattle allele frequency was 0.174. On 1229 pigs (both females and castrated males) the weight and the hearth girth were measured during growth. Additionally, some body measures (height at withers and at rump, length of the body, fore–rear length of the thigh, and width of the rump) were recorded on a random set of 305 pigs from the 1229 pigs. Heritability estimates of Gompertz growth curve parameters for weight were high (0.671; 0.448; 0.249 for parameters A, b and c, resp.), so indicating their utility for selection purposes. Significant effects of the genotype at the wattle locus on growth and body measures were shown. Wattled pigs showed a significantly lower body weight at maturity (6.4%) than non wattled pigs (P<0.05), as no significant differences were shown for the rate of growth and the age at maturity (P>0.05). Moreover, wattled pigs showed a significantly reduced height at withers (10.5%), height at rump (11.3%), body length (11.0%), ham length (14.2%), rump width (19.0%) and chest circumference (19.6%) at maturity. They grew significantly faster in dimensions and reached maturity significantly earlier than non wattled pigs (P<0.05).