Multi-trait and repeatability models for genetic evaluation of litter traits in pigs considering different farrowings

Abstract

SUMMARYWe aimed to compare multi-trait and repeatability models to estimate genetic parameters for the traits number of piglets born alive (NBA) and alive at 3 week of age (NP3), litter weight at birth (LW0) and at 3 week of age (LW3), and mean piglet weight at birth (MW0) and at 3 week of age (MW3), considering the first three farrowings of Landrace sows. Heritability (h 2 ) estimates showed an increasing pattern up to the third farrowing for LW0 and MW3. For NBA, NP3, LW3, and MW0 h 2 increased from the first to the second and decreased from the second to the third farrowing. In general, heritability estimated in the repeatability model was lower than the mean of the estimates in the multi-trait model. The traits LWO, MW0, and MW3 presented high genetic correlation among different farrowings (0.961-0.997), while NBA, NP3, and LW3 (0.092-0.986) presented irregular values among farrowings. The corrected Akaike information criterion shows that the repeatability model is not indicated for almost all of the studied traits. These results indicate that the multi-trait model is recommended for genetic evaluation of the traits number of piglets born alive and alive at 3 week of age, litter weight and mean piglet weight at birth and 3 week of age, in different farrowings, as different traits.

Genetic parameters for litter traits at different parities in purebred Landrace and Yorkshire pigs

“…Although Irgang, Fávero, and Kennedy () and Noguera et al () found that the heritability increased with increasing parity number, the results observed in this study were essentially opposite. The heritability across parities in this work showed no trend with the increasing number of parity, which corroborates with the prior studies of Alfonso, Noguera, Babot, and Estany () and Costa et al ().…”

“…Overall, heritability estimates analyzed using a multi‐trait model for each trait at different parities were found to be higher than those in the repeatability analyses of both breeds, which might be explained by the simplicity of the model. Costa et al () who also compared the multi‐trait and repeatability models used for genetic evaluations of litter traits in Landrace pigs for different farrowings reported that the estimated heritability in the repeatability model was lower than the mean of the estimates in the multi‐trait model. The heterogeneity of heritability observed in this study suggests that different parities should be considered as different traits, which is also in agreement with the results of Fernández et al ().…”

“…Overall, heritability estimates analyzed using a multi-trait model for each trait at different parities were found to be higher than those in the repeatability analyses of both breeds, which might be explained by the simplicity of the model. Costa et al (2016) estimation when compared to the repeatability model as the former assumes homogeneity of variance across parities. Ye, Wu, Tan, Hu, and Wang (2018) who estimated the genetic correlation between parities 1 to 5 for the number of deformed fetuses of Yorkshire pigs also reported that the correlations between the first parity and other parities ranged from −0.07 to 0.17, with ranges of 0.19 to 0.71 if the first parity was excluded.…”

“…Repeatability models assume a genetic correlation of unity between all pairs of records, equal variance for all records and equal environmental correlations between all pairs of records (Mrode, ). Several studies have reported that the estimates of genetic correlations between the first and later parities in litter traits are often less than one and the genetic basis of reproductive performance in sows could change in different parities (Costa et al, ; Fernández, Rodrigáñez, Zuzúarregui, Rodríguez, & Silió, ; Hermesch, Luxford, & Graser, ; Noguera, Varona, Babot, & Estany, ). Therefore, multi‐trait models that consider subsequent records as different traits are preferred in such situations to increase the efficiency of selection.…”

Case Study on Increasing Breeding Value Estimation Reliability of Reproductive Traits in Serbian Highly Prolific Large White and Landrace Sows

“…Numerous studies have confirmed that genetic progress in the overall reproductive performance of sows can be most effectively achieved by selection for litter size [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Postnatal litter size can be described as the NBA, stillborn, total born and weaned piglets.…”