Methods to predict lameness in sows

Authors: Rohrer, Gary; OSTRAND, LEXI - University Of Nebraska; Rempel, Lea; SCHMIDT, TY - University Of Nebraska; MOTE, BENNY - University Of Nebraska

Submitted to: International Society for Animal Genetics (ISAG)
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective was to identify traits recorded at 5 months of age predictive of future lameness. Mobility was measured using a pressure-sensing mat (GAIT4) and 7 days of video recorded daily activity (NUtrack). Gilts (n=3659) were evaluated for the study, but only 2172 gilts had data for both systems. Gilts were assigned codes to describe their lifetime soundness. Animals retained for breeding and never detected with mobility issues were recorded as sound (SND), while retained animals that became lame were coded as lame sow (LSW). Culled gilts were in 3 categories: culled for leg structure (STR), visibly lame gilt (LGT) and other reasons (CLL). GAIT4 system creates a series of measurements for each foot related to pressure, duration and step length of each foot and a lameness score for each foot. Traits used to predict an animal’s mobility status summarized values for all 4 feet: average step length, average stance time, standard deviation of stance time, variance of lameness score and variance of total scaled pressure. NUtrack measurements were rotations, velocity, distance walked and times spent eating, sitting, standing, lying sternal and lying lateral. Mixed model analyses were conducted in R fitting fixed effects of breed of sire, contemporary group and soundness score, with animal fit as a random effect. Heritability was estimated using animal effects from R models as phenotypes in WOMBAT, with 3 generations of pedigree. Analyses of GAIT4 measures found LGT and STR gilts had longer average stance time, greater variance of lameness scores and took shorter steps; estimates of heritability ranged from 0.23-0.28. NUtrack measurements predictive of soundness score were time eating, time standing, time lying lateral, distance walked and rotations. LGT and STR were less active and spent more time lying lateral than other animals. In addition, SND animals had more rotations and tended to have greater distance than LSW. Estimates of heritability for NUtrack measurements ranged from 0.21 and 0.31. Overall, NUtrack traits at 5 months of age predicted soundness and were heritable providing producers with traits to select gilts and improve mobility of future generations of pigs. USDA is an equal opportunity employer.