Competing risk analyses of longevity in Duroc sows with a special emphasis on leg conformation
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Publication date
2009-01-01Abstract
A competing risk approach was used to evaluate the influence of several factors on culling risk for 587 Duroc sows. Three
different analyses were performed according to whether sow failure was due to death during productive life (DE) or to one of
two causes for voluntary culling: low productivity (LP) and low fertility (LF). Sow survival was analyzed by the Cox model. Year
at first farrowing (batch effect) significantly affected sow survival in all three analyses ( P < 0.05 for DE and P < 0.001 for LP
and LF) whereas farm of origin accounted for relevant variation in the LP and LF analyses. LP culling increased with backfat
thickness of more than 19 mm at the end of the growth period ( P < 0.05), bad teat condition ( P < 0.05) and reduced piglets
born alive ( P < 0.001). For the LF competing risk analysis, culling increased with age at first farrowing ( P < 0.1). Special
emphasis was placed on the influence of leg and teat conformation on sow survivability, although they did not affect sow
failure due to DE ( P > 0.1). The overall leg-conformation score significantly influenced sow longevity in LP ( P < 0.001) and
LF competing risk analyses ( P < 0.001), showing a higher hazard ratio (HR) for poorly conformed sows (1.013 and 4.366,
respectively) than for well-conformed sows (0.342 and 0.246, respectively). Survival decreased with the presence of abnormal
hoof growth in LP and LF analyses (HR 5 3.372 and 6.002, respectively; P < 0.001) and bumps or injuries to legs (HR 5 4.172
and 5.839, respectively; P < 0.01). Plantigradism reduced sow survival in the LP analysis ( P < 0.05), while sickle-hooked leg
( P < 0.05) impaired sow survival in the fertility-specific analysis. Estimates of heritability for longevity related to LP culling
ranged from 0.008 to 0.024 depending on the estimation procedure, whereas heritability values increased to between 0.017
and 0.083 in LF analysis. These analyses highlighted substantial discrepancies in the sources of variation and genètic
background of sow longevity depending on the cause of failure. The estimated heritabilities suggested that direct genetic
improvement for sow longevity seemed feasible, although only a small genetic progress was expected.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
575 - General genetics. General cytogenetics
619 - Veterinary science
Pages
8
Publisher
Elsevier
Is part of
Animal
Citation
De Sevilla, X. Fernàndez, E. Fàbrega, J. Tibau, and J. Casellas. 2009. “Competing Risk Analyses of Longevity in Duroc Sows With a Special Emphasis on Leg Conformation.” Animal 3 (3): 446–453. doi: 10.1017/s1751731108003583
Grant agreement number
EC/FP6/506508/EU/Integration of animal welfare in the food quality chain: from public concern to improved welfare and transparent quality/WELFARE QUALITY
Program
Benestar Animal
Genètica i Millora Animal
This item appears in the following Collection(s)
- ARTICLES CIENTÍFICS [2692]
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by-nc-nd/4.0/