Effects of Divergent Selection for Leg Weakness on Angularity of Joints in Duroc Swine

Abstract

Sixty Duroc pigs, representing offspring of three lines from the fifth generation of divergent selection for leg weakness, were examined to determine correlated responses in joint angularity. The lines were low, control, and high, with the latter having superior front leg structure. At approximately 100 kg, 10 pigs of each sex and line were scored for front and rear leg structure and movement. The shoulder, elbow, carpal and hock joints were measured for resting angles and range of motion. The model to analyze the data included the effects of line, sire, sex and side and a covariable for weight. High-line pigs had significantly smaller (P < .05) resting angles of the elbow joint than did control-or low-line pigs. The low-line pigs, however, had significantly smaller resting angles at the carpal joint (P < .01) and greater resting angles at the hock joint (P < .05) than did control-or high-line pigs. The low-line pigs had fewer degrees extension at the elbow joint and fewer degrees flexion at the carpal joint than did control-or high-line pigs. High-line pigs had fewer degrees of flexion of the elbow joint than did control-or low-line pigs. Resting angles and range of motion for the elbow and carpal joints were less on the left side than on the right side. Males had greater degrees of extension and total degrees of movement at the elbow joint than did females. Selection for different degrees of leg weakness resulted in accompanying alterations in angularity of joints. ABSTRACTSixty Duroc pigs, representing offspring of three lines from the fifth generation of divergent selection for leg weakness, were examined to determine correlated responses in joint angularity. The lines were low, control, and high, with the latter having superior front leg structure. At approximately 100 kg, 10 pigs of each sex and line were scored for front and rear leg structure and movement. The shoulder, elbow, carpal and hock joints were measured for resting angles and range of motion. The model to analyze the data included the effects of line, sire, sex and side and a covariable for weight. High-line pigs had significantly smaller (P < .05) resting angles of the elbow joint than did control-or low-line pigs. The low-line pigs, however, had significantly smaller resting angles at the carpal joint (P < .01) and greater resting angles at the hock joint (P < .05) than did control-or high-line pigs. The low-line pigs had fewer degrees extension at the elbow joint and fewer degrees flexion at the carpal joint than did control-or high-line pigs. High-line pigs had fewer degrees of flexion of the elbow joint than did control-or low-line pigs. Resting angles and range of motion for the elbow and carpal joints were less on the left side than on the right side. Males had greater degrees of extension and total degrees of movement at the elbow joint than did females. Selection for different degrees of leg weakness resulted in accompanying alterations in angularity of joints.

Mapping quantitative trait loci for principal components of bone measurements and osteochondrosis scores in a wild boar × Large White intercross

“…Many studies of associations between growth rate and osteochondrosis have been performed, the results most often showing weak and inconsistent correlations (Lundeheim, 1987 ;Nakano et al, 1987 ;Hill, 1990 b ;Stern et al, 1995 ;Uhlhorn et al, 1995). Selection for different degrees of leg weakness has been shown to result in alterations in bone length and width (Draper et al, 1992) and in angularity of joints (Draper et al, 1988). However, the correlated response on osteochondrosis was negligible in the same selection experiment .…”

SNP detection and comparative linkage mapping of 66 bone-related genes in the pig

“…Unsoundness of feet and leg influences the reproductive performance and health of sows and boars (Wood, 2001). Feet and leg soundness depends on the joint angularity in legs (Draper et al, 1988), skeletal morphogenesis, bone mineral density and remodeling cycle of bones (Massaro and Rogers, 2004). These structural and functional attributes of dynamic bone growth are determined by the influence of both intrinsic (chemical) signals and extrinsic (mechanical) signals.…”

Vitamin C Plasma Concentrations and Leg Weakness in the Forelegs of Growing Pigs

“…Leg weakness can be manifested as crooked and/or bent forelegs (Grøndalen, 1974c; Reiland, 1978c; Nielsen and Vinther, 1982). Deformed forelegs have been associated with OC/OCD (Jørgensen et al., 1995), ulnar dyschondroplasia (Reiland, 1978c), Mycoplasma hyosynoviae arthritis (Lawrisuk et al., 1987), genetic predisposition (Draper et al., 1988; Rothschild and Christian, 1988; Jørgensen and Vestergaard, 1990), contraction of the flexor tendons and vitamin C deficiency (Nielsen and Vinther, 1982; Cleveland et al., 1987; Draper et al., 1988).…”