Effective Selection for Lower Mortality in Organic Pigs through Selection for Total Number Born and Number of Dead Piglets

Abstract

Selection for the number of living pigs on day 11 (L11) aims to reduce piglet mortality and increase litter size simultaneously. This approach could be sub-optimal, especially for organic pig breeding. This study evaluated the effect of selecting for a trait by separating it into two traits. Genetic parameters for L11, the total number born (TNB), and the number of dead piglets at day 11 (D11) were estimated using data obtained from an organic pig population in Denmark. Based on these estimates, two alternative breeding schemes were simulated. Specifically, selection was made using: (1) a breeding goal with L11 only versus (2) a breeding goal with TNB and D11. Different weightings for TNB and D11 were tested. The simulations showed that selection using the first breeding scheme (L11) produced lower annual genetic gain (0.201) compared to the second (TNB and D11; 0.207). A sensitivity analysis showed that the second scheme performed better because it exploited differences in heritability, and accounted for genetic correlations between the two traits. When the second breeding scheme placed more emphasis on D11, D11 declined, whereas genetic gain for L11 remained high (0.190). In conclusion, selection for L11 could be optimized by separating it into two correlated traits with different heritability, reducing piglet mortality and enhancing L11.

A bio-economic model for estimating economic values of important production traits in the black soldier fly (Hermetia illucens)

“…Previous studies show it is best to avoid combined traits in a breeding goal since the direction of selection is more complicated with these types of traits. A better alternative is to include both traits in the breeding goal and apply directional selection for each trait separately (Zaalberg et al, 2022;Zetouni et al, 2017). Hence, to guarantee the highest genetic gain for growth rate, it would be best to select for higher larval mass and shorter development time simultaneously through multi-trait selection (Hansen, 2024;Zaalberg et al, 2022;Zetouni et al, 2017).…”

Animal Health and Productivity of Organic Greek Pig Farms: The Current Situation and Prospects for Sustainability

“…The number of dead piglets in a litter can be reduced by certain management practices, such as the use of modified farrowing houses for sows, cross-feeding, and better support of sows at birth [ 40 , 41 ]. However, improvements in breeding animal selection could also lead to a decrease in piglet mortality [ 42 ]. Schild et al reported that another factor related to high piglet mortality is the large litter sizes obtained by using highly productive sow lines and suggested a switch to less productive genetics to produce hybrids suitable for organic farming [ 43 ].…”

Genetic and phenotypic time trends of litter size, piglet mortality, and birth weight in pigs

“…By then the selection criterion had been changed to the number of surviving piglets at day 5, and Christensen et al (2018, their Figures C1 to C3) reported 2016 levels of 18.0 average total born, a farrowing mortality rate of 9.4%, and a lactation mortality rate of 13.5%. However, Henryon et al (2022) and Zaalberg et al (2022) noticed that the revised selection criterion was still not sufficiently balanced, and would benefit from a two-trait approach (total number born and survival rate) rather than a single trait one; this was implemented in 2022 (https://tinyurl.com/2p8s6f7s).…”