Estimates of Breed Differences and Genetic Parameters of Pig Temperament Scores during a Performance Test and its Relationship with Performance Traits

pigs;temperament;performance;breeds

Yoder, Chad Lewis ; Dr. M. Todd See, Committee Chair,Dr. Joe Cassady, Committee Member,Dr. William L. Flowers, Committee Member,Dr. Christian Maltecca, Committee Member,Dr. David Dickey, Committee Member,Yoder, Chad Lewis ; Dr. M. Todd See ; Committee Chair ; Dr. Joe Cassady ; Committee Member ; Dr. William L. Flowers ; Committee Member ; Dr. Christian Maltecca ; Committee Member ; Dr. David Dickey ; Committee Member

University:North Carolina State University

关键词: pigs;    temperament;    performance;    breeds;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/6355/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

YODER, CHAD LEWIS. Estimates of Breed Differences and Genetic Parameters of PigTemperament Scores during a Performance Test and its Relationship with PerformanceTraits. (Under the direction of Dr. M. Todd See).The objective of this study was to estimate breed differences for temperament scoresduring a performance test, and estimate the genetic parameters associated with temperamentand performance traits. Chester White (CW), Duroc (D), Landrace (L), and Yorkshire (Y)boars and gilts (n=4,774) were used to estimate breed differences in temperament and geneticparameters. Adjusted backfat (BF), adjusted loin depth (LD), days to 113.4 kilograms(DAYS), estimated percent fat-free lean (LEAN), and three temperament scores: load score(LS), scale score (SS), and vocal score (VS) were recorded. All scores ranged from 1 (calm)to 5 (highly excited). While loading into the scale LS was recorded; SS and VS wererecorded while in the scale as ultrasound measurements were taken.Temperament scores were evaluated as categorical traits with statistical modelsincluding fixed effects of breed, sex, contemporary group (barn-farm-test date), and off-testweight as a covariate. Order in which pigs were loaded into the scale was included in themodel for LS. After initial analysis it was determined VS was best described as twocategories, vocal and non-vocal, and was analyzed as a binary trait. Statistical models for BF,LD, DAY, and LEAN included fixed effects of breed, sex, and LS, SS, or VS. Growth ratewas adjusted to 113.4 kilograms, while BF and LD were adjusted to the mean weight of therespective breed. Breed differences for LS, SS, and VS were estimated as odds ratios.The odds of increased LS were greater for L (1.62, 1.30; P < 0.01) than D and Yrespectively. Landrace had a greater (P < 0.01) probability of a higher SS and VS comparedto CW (1.77, 2.37), D (3.31, 3.94) and Y (2.51, 2.46). Yorkshire had greater odds ofincreased LS (1.25), SS (1.32), and VS (1.60) than D. Chester White had a greaterprobability of increased LS and SS than D (1.58, 1.87) and Y (1.26, 1.42). Chester Whitewere 1.66 (P < 0.01) times more likely to have a higher VS than D.Genetic models for LS, SS, VS and performance traits were the same as those used toestimate breed differences. However, breed as a fixed effect was excluded and separateanalysis was conducted for each breed, and temperament scores were not included in modelsfor performance traits. Variance components were estimated using THRGIBBS1F90 with150,000 cycles, a 20,000 cycle burn in period, and every 20th sample was stored. Estimates ofparameters of interest were obtained as statistics of their respective posterior distributions.Direct heritability estimates were (CW, D, L, Y): LS (0.05, 0.06, 0.06, 0.05), SS(0.22, 0.09, 0.09, 0.10), and VS (0.27, 0.24, 0.37, 0.21). Estimated heritability of LS was lowregardless of breed. Heritability estimates for SS, were low with the exception of CW.Heritability estimates for VS were moderate. Direct genetic correlations between SS and VSobtained in a bivariate model were positive and moderate (0.30 to 0.75) indicating that pigsthat are more active in the scale are also more vocal. Genetic correlations betweentemperament traits varied between breed, but were generally moderate and positive. Thegenetic correlations between LS, SS, and VS with BF, LD, DAYS, and LEAN ranged from -0.78 to 0.56, and varied among breeds. Based on these results selection for temperamentscores collected during a performance test provide potential to alter pig behavior. However,progress in performance traits may be affected if selection for temperament is practiced,while current selection criteria may result in changes in temperament.