Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602, USA.
Topigs Norsvin Research Center, Beuningen, GE 6641 SZ, The Netherlands.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad067.
The swine inflammation and necrosis syndrome (SINS) is a syndrome visually characterized by the presence of inflamed and necrotic skin at extreme body parts, such as the teats, tail, ears, and claw coronary bands. This syndrome is associated with several environmental causes, but knowledge of the role of genetics is still limited. Moreover, piglets affected by SINS are believed to be phenotypically more susceptible to chewing and biting behaviors from pen mates, which could cause a chronic reduction in their welfare throughout the production process. Our objectives were to 1) investigate the genetic basis of SINS expressed on piglets' different body parts and 2) estimate SINS genetic relationship with post-weaning skin damage and pre and post-weaning production traits. A total of 5,960 two to three-day-old piglets were scored for SINS on the teats, claws, tails, and ears as a binary phenotype. Later, those binary records were combined into a trait defined as TOTAL_SINS. For TOTAL_SINS, animals presenting no signs of SINS were scored as 1, whereas animals showing at least one affected part were scored as 2. Apart from SINS traits, piglets had their birth weight (BW) and weaning weight (WW) recorded, and up to 4,132 piglets were later evaluated for combined skin damage (CSD), carcass backfat (BF), and loin depth (LOD). In the first set of analyses, the heritability of SINS on different body parts was estimated with single-trait animal-maternal models, and pairwise genetic correlations between body parts were obtained from two-trait models. Later, we used four three-trait animal models with TOTAL_SINS, CSD, and an alternative production trait (i.e., BW, WW, LOD, BF) to access trait heritabilities and genetic correlations between SINS and production traits. The maternal effect was included in the BW, WW, and TOTAL_SINS models. The direct heritability of SINS on different body parts ranged from 0.08 to 0.34, indicating that reducing SINS incidence through genetic selection is feasible. The direct genetic correlation between TOTAL_SINS and pre-weaning growth traits (BW and WW) was favorable and negative (from -0.40 to -0.30), indicating that selection for animals genetically less prone to present signs of SINS will positively affect the piglet's genetics for heavier weight at birth and weaning. The genetic correlations between TOTAL_SINS and BF and between TOTAL_SINS and LOD were weak or not significant (-0.16 to 0.05). However, the selection against SINS was shown to be genetically correlated with CSD, with estimates ranging from 0.19 to 0.50. That means that piglets genetically less likely to present SINS signs are also more unlikely to suffer CSD after weaning, having a long-term increase in their welfare throughout the production system.
猪炎症和坏死综合征（SINS）是一种综合征，其特征是在身体的极端部位出现发炎和坏死的皮肤，如乳头、尾巴、耳朵和爪子冠状带。这种综合征与几种环境因素有关，但对遗传因素的了解仍然有限。此外，患有 SINS 的仔猪被认为在表型上更容易受到同笼仔猪咀嚼和咬伤的影响，这可能导致它们在整个生产过程中的福利受到慢性降低。我们的目标是 1）研究仔猪不同身体部位 SINS 表达的遗传基础，2）估计 SINS 遗传与断奶后皮肤损伤和断奶前和断奶后生产性状的关系。共有 5960 头 2-3 天大的仔猪对乳头、爪子、尾巴和耳朵的 SINS 进行了二元表型评分。后来，这些二元记录被合并为一个定义为 TOTAL_SINS 的特征。对于 TOTAL_SINS，没有出现 SINS 迹象的动物被评为 1，而至少有一个受影响部位的动物被评为 2。除了 SINS 特征外，仔猪还记录了其出生体重（BW）和断奶体重（WW），多达 4132 头仔猪后来还评估了联合皮肤损伤（CSD）、胴体背膘（BF）和腰深（LOD）。在第一组分析中，使用单性状动物-母体模型估计了不同身体部位 SINS 的遗传力，并从两性状模型中获得了身体部位之间的成对遗传相关性。后来，我们使用四个三性状动物模型，使用 TOTAL_SINS、CSD 和替代生产性状（即 BW、WW、LOD、BF）来评估 SINS 与生产性状之间的性状遗传力和遗传相关性。母体效应包含在 BW、WW 和 TOTAL_SINS 模型中。不同身体部位 SINS 的直接遗传力在 0.08 到 0.34 之间，表明通过遗传选择降低 SINS 发生率是可行的。TOTAL_SINS 与断奶前生长性状（BW 和 WW）的直接遗传相关性是有利的和负相关的（从-0.40 到-0.30），表明选择遗传上不太可能出现 SINS 迹象的动物将对仔猪出生和断奶时体重较重产生积极影响。TOTAL_SINS 与 BF 和 TOTAL_SINS 与 LOD 之间的遗传相关性较弱或不显著（-0.16 到 0.05）。然而，对 SINS 的选择被证明与 CSD 在遗传上相关，估计值在 0.19 到 0.50 之间。这意味着遗传上不太可能出现 SINS 迹象的仔猪在断奶后也不太可能出现 CSD，从而在整个生产系统中提高了它们的福利。
