Effects of Dietary Chelated Minerals and Methionine during Rearing on Gilt Lameness, Growth, and Performance before and after Entering Production

Lameness is a multifactorial condition, cause of early culling, and thought to be influenced by genotype, nutritional components, growth rate, mechanical stress, and claw health. The present study evaluated the effect of key nutrients for cartilage and bone development fed to rearing gilts (134 d) on lameness, performance, body composition and any carry-over effect entering into the sow farm. Gilts (n=360) with 28.8 ± 8.8 kg of initial BW were blocked and allocated in 4 treatments: control (C, basal diet); adding 15, 20 and 50 mg/kg of chelated minerals Cu, Mn, and Zn, respectively (MIN); 102% methionine: lysine ratio (MET); and the combination (MM). Lameness, BW, and body composition were measured 7 times during growth; and over the first productive phases. At d 45 of rearing, all gilts were inoculated with field strain of PRRSV because an outbreak in the sow farm prompted prophylactic measures. The procedures ANOVA, repeated measures (including sow as random effect), logistic regression, and Fisher Exact test were used. Probabilities of lameness increased (P<0.01) with BW during rearing. Prevalence was 7.75% and lameness was detected in a BW confidence interval of 106.8 to 129.7 kg. After detection, lame gilts showed lower (P<0.05) BW and ADG than none-lame gilts. Highest probabilities of developing lameness during rearing were found for C (14% vs. <7% for others, P<0.01). In the sow herd, 21% of sows showed lameness with 56% eventually recovering. Of lameness, 24% were caused by claw lesions. Prevalence of lameness was 10.8% in control-service area, 8.5% after group-housing and 14.8% in lactation. Compared to other groups, C showed increased lameness risk during lactation (20% vs. <12%, P<0.01). Of sows entering the sow herd, 27.3% were culled before third gestation. Sow productivity was unaffected by treatments (P>0.05). Higher removal rate for lameness was observed for C (7:10) and MM (3:10) compared to no cases in MIN and MET (P<0.01). Lame gilts during rearing weaned 1.2 piglets less (P<0.05). On farm lameness caused 0.7 more stillborn (P<0.10), 1 mm more BF loss in first lactation (P<0.05), and increased weaning-to-estrus interval by 3 d. Therefore, trace minerals and methionine supplemented to rearing gilts can reduce gilt culling by decreasing lameness incidence and improving claw health. A positive relationship was not found between growth rate (926-944 g/d) and lameness in gilts fed ad libitum. Lameness appeared around 106 kg, risk increased with BW and after clinical signs compromised growth and further performance.