Swine Inflammation and Necrosis Syndrome (SINS)

Screening of Piglets for Signs of Inflammation and Necrosis as Early Life Indicators of Animal Health and Welfare Hazards

Ensuring animal health and well-being requires animal-based measures for early and direct intervention at the point of care. Insight into the pathophysiology of Swine Inflammation and Necrosis Syndrome (SINS) has led to a non-invasive, clinical scoring system that can be used in daily practice. This provides information on the cause of observed lesions for direct intervention in affected herds. The aim of the current study was to re-evaluate the practicality of the SINS scoring system under field conditions. In addition, this is the first study to provide insight into the prevalence of SINS on Dutch farms. This study involved the scoring of 5958 piglets from 20 visits on 13 farms randomly selected by a veterinary practice in the Netherlands. The results showed that up to 64.1% of the piglets had visible inflammatory alterations in different body parts within the first seven days of life. Sow rectal temperature, signs of coprostasis and water intake during pregnancy were significantly (p ≤ 0.05) correlated with the prevalence of SINS in piglets. In conclusion, the SINS scoring system is an easy-to-use, non-invasive diagnostic tool that summarises animal-based observations at the point of care, providing a valuable communication tool between farmers, nutritionists and veterinarians in their efforts to improve animal health and welfare.

Tail status at both individual and pen level affects tail biting victimisation in pigs over the finishing period

Tail biting is a significant welfare problem in commercial pig production. Individual tail health was assessed in non-docked pigs (n = 1 579) on five farms (180-441 pigs and 16-30 pens per farm) at introduction to the finishing unit (W0) and 9 weeks later (W9) to present longitudinal descriptive data, establish risk factors for being tail bitten and investigate possibilities to infer information about W0 tail health based on W9 tail appearance. Tail health was described in terms of posture (hanging), shortening (loss of distal flattening), lesion type (TLT; 0 = no lesion, 1 = minor lesion on intact skin; or with skin penetration 2 = < 0.5 cm, 3 = 0.5-2 cm, or 4 = > 2 cm), length (iL) and change therein from W0 to W9 (ΔL). ΔL may include cumulating information on received tail biting given that the variation was large and negative values were present. The average intact tail measured 22 ± 2.1 and 29 ± 2.3 cm at W0 and W9, respectively, with no effect of sex. Tail lesion prevalence decreased unexpectedly from W0 to W9, possibly due to a docking-like effect in the present population showing a relatively high injury prevalence at W0. Mixed models predicting tail health at W9 were built with pig (n = 1 323-1 492) as statistical unit and pen (n = 94-124) nested within farm as random effects. Pen-level tail appearance at W0 was included as eligible predictors. No model predicted TLT 2,3 or 4 at W9, suggesting that factors other than early tail appearance determined late victimisation. A larger ΔL was predicted by the individual-level factors barrow (vs female), a larger iL, no tail shortening and any other TLT as compared to 4 in the individual at W0; as well as smaller percentage of hanging tails in the pen, a larger average iL in the pen (px̅L) and an interaction between iL and px̅L. According to the interaction effect, two different scenarios predicted a smaller ΔL: smaller iL and px̅L, or especially larger iL and px̅L. The scenarios may be re-targeting of previous victims by individuals accustomed to an environment with tail biting and two-stage tail-biting where the longest tails were the most attractive objects for exploration. We conclude that pigs with better tail health at introduction to the finishing unit receive less injurious biting during 9 weeks. Pen-level tail health has a profound effect that is very different at extremes of tail length. One-fourth of early skin-penetrating tail injuries may not be detectable shortly before slaughter.

Screening for transcriptomic associations with Swine Inflammation and Necrosis Syndrome

BACKGROUND

The recently identified swine inflammation and necrosis syndrome (SINS) affects tail, ears, teats, coronary bands, claws and heels of affected individuals. The primarily endogenous syndrome is based on vasculitis, thrombosis, and intimal proliferation, involving defence cells, interleukins, chemokines, and acute phase proteins and accompanied by alterations in clinical chemistry, metabolome, and liver transcriptome. The complexity of metabolic alterations and the influence of the boar led to hypothesize a polygenic architecture of SINS. This should be investigated by a transcriptome study. For this purpose, the three to five least affected (SINS-low) and most SINS affected (SINS-high) 3d-old piglets, each of three boars, a relatively SINS stable Duroc boar (DU), a relatively stable Pietrain boar (PI+) and a highly susceptible Pietrain boar (PI-) were selected from 27 litters of mixed semen to minimize environmental effects.

RESULTS

A genome-wide expression experiment revealed a huge set of differentially expressed genes that are involved in vasculitis, inflammation and necrosis, keratinization and erythrocyte epitopes. Among them were CRP, GYPA, S100A12, and LIPK. The results confirm and complement previous studies to this topic.

CONCLUSIONS

The results confirm the outstanding importance of defence in the context of SINS. At the same time, for the first time, there is evidence for a direct involvement of the keratinisation capacity of the skin and various epitopes of the erythrocyte membrane, which seem to be associated with the severity of SINS. These genes could serve to clarify the pathogenesis of the syndrome and to develop diagnostic tools in future studies.

A Look Inside-Histopathological Examinations of Different Tail Tip Lesions in Dairy Cows

Feedlot cattle are frequently affected by inflammation and necrosis of the tail tips, resulting in impeded animal welfare and economic losses. In a recent study, it was demonstrated that dairy cows are also affected by different lesions of the tail tip, including alopecia, annular constrictions, crusting, scaling and swelling. Despite the frequent occurrence of these lesions, the underlying etiology and pathomechanisms are unclear to date. To gain insight into this malady, we histopathologically examined 16 tail tips of slaughtered dairy cows, representing the entire range of different lesions. While macroscopically alopecic areas were characterized by the formation of granulation tissue in the dermis with an inconspicuous epidermis, we found not only dermal granulation tissue but also purulent-necrotizing inflammation with the breakdown of the basement membrane in encrusted lesions. Interestingly, in some cases, we found areas of coagulation necrosis of the epidermal and dermal layers in the crusts. Tails with macroscopical scaling were affected by ortho- and/or parakeratotic hyperkeratosis, and, in tails with macroscopical swelling, we observed a low-protein edema of the central longitudinal connective tissue of the tail. We conclude that the observed lesions might be caused by ischemia of the skin in the distal parts of the tail.

Foot lesions and forelimb skin abrasions in suckling piglets: development and risk factors

BACKGROUND

Foot lesions in suckling piglets have been associated with poor flooring in several studies and were recently proposed to be indicative of swine inflammatory and necrosis syndrome. However, identical findings are also the typical outcome of various non-infectious causes; thus, further risk analysis is needed. The objective of this study was to describe the development of heel bruising, coronary band lesions and forelimb skin abrasion in suckling pigs up to 5 days of age. Furthermore, the effects of various intrinsic and extrinsic factors were examined. On each of four commercial piglet-producing farms, piglets from two or three batches of eight sows were studied. The piglets were included within 18 h after birth. Each piglet was individually scored four times. The score for the heels differentiated six (0-5) and for the coronary band and forelimb skin abrasion three stages (0-2). The body weight was measured two times. The effect of the floor was estimated by allocating the sows randomly to farrowing pens equipped with either soft rubber mats covered with litter or fully slatted plastic floors.

RESULTS

The final analysis comprised data from 1045 piglets. Foot lesions were not found at birth but started to develop on day 1. On day 5, heel bruising was found in 94%, main claw coronary band lesions in 49% and forelimb skin abrasion in 73% of the piglets. In a multifactorial logistic regression analysis, it was shown that a slatted plastic floor significantly increased the odds of heel bruising and coronary band lesions, while a rubber floor with litter increased the odds of forelimb skin abrasions.

CONCLUSION

Foot and forelimb lesions in new-born piglets are mainly induced by the floor. The effect of slatted plastic floors on heel bruising showed an overwhelming OR of 52.89 (CI 26.29-106.43). Notably, coronary band lesions in young suckling piglets occur on slatted as well as non-slatted floors, indicating that the piglets incur these injuries not only from the wedging of their feet into the gaps between slats but also from contact with the floor while suckling. Based on these findings, preventive measures should be redirected to the improvement of the floor in the farrowing pen, particularly in the area under the sow's udder.

GWAS reveals genomic associations with swine inflammation and necrosis syndrome

The recently identified swine inflammation and necrosis syndrome (SINS) occurs in high prevalence from newborn piglets to fattening pigs and resembles an important concern for animal welfare. The primary endogenous syndrome affects the tail, ears, teats, coronary bands, claws and heels. The basis of clinical inflammation and necrosis has been substantiated by histopathology, metabolomic and liver transcriptomic. Considerable variation in SINS scores is evident in offspring of different boars under the same husbandry conditions. The high complexity of metabolic alterations and the influence of the boar led to the hypothesis of a polygenic architecture of SINS. This should be investigated by a genome-wide association study. For this purpose, 27 sows were simultaneously inseminated with mixed semen from two extreme boars. The mixed semen always contained ejaculate from a Pietrain boar classified as extremely SINS susceptible and additionally either the ejaculate from a Pietrain boar classified as SINS stable or from a Duroc boar classified as SINS stable. The 234 piglets were phenotyped on day 3 of life, sampled and genetically assigned to the respective boar. The piglets showed the expected genetic differentiation with respect to SINS susceptibility. The suspected genetic complexity was confirmed both in the number and genome-wide distribution of 221 significantly associated SNPs, and led to 49 candidate genes. As the SNPs were almost exclusively located in noncoding regions, functional nucleotides have not yet been identified. The results suggest that the susceptibility of piglets to SINS depends not only on environmental conditions but also on genomic variation.

Are biters sick? Health status of tail biters in comparison to control pigs

BACKGROUND

Tail biting is a multifactorial problem. As the health status is one of the factors commonly linked to tail biting, this study focuses on the health of identified biters. 30 (obsessive) biters are compared to 30 control animals by clinical and pathological examination as well as blood and cerebrospinal fluid samples. In that way, altogether 174 variables are compared between the groups. Moreover, connections between the variables are analysed.

RESULTS

In the clinical examination, 6 biters, but only 2 controls (P = 0.019) were noticeably agitated in the evaluation of general behaviour, while 8 controls were noticeably calmer (2 biters, P = 0.02). Biters had a lower body weight (P = 0.0007) and 13 biters had overlong bristles (4 controls, P = 0.008). In the pathological examination, 5 biters, but none of the controls had a hyperceratosis or inflammation of the pars proventricularis of the stomach (P = 0.018). However, 7 controls and only 3 biters were affected by gut inflammation (P = 0.03). In the blood sample, protein and albumin levels were below normal range for biters (protein: 51.6 g/l, albumin: 25.4 g/l), but not for controls (protein: 53.7 g/l, albumin: 27.4 g/l), (protein: P = 0.05, albumin: P = 0.02). Moreover, 14 biters, but only 8 controls had poikilocytosis (P = 0.05). Although not statistically different between groups, many animals (36/60) were affected by hypoproteinemia and hyponatremia as well as by hypokalemia (53/60) and almost all animals (58/60) had hypomagnesemia. For hypomagnesemia, significant connections with variables linked to tail damage and ear necrosis were detected (rs/V/ρ ≥ 0.4, P ≤ 0.05).

CONCLUSION

The results suggest that behavioural tests might be helpful in identifying biters. Moreover, cornification and inflammation of the pars proventricularis is linked to becoming a biter. Furthermore, the results highlight the need for appropriate and adjusted nutrient and mineral supply, especially with regard to magnesium.

Entzündungs- und Nekrosesyndrom des Schweins (SINS) – eine Übersicht

Entzündungen und Teilverluste des Schwanzes treten in hoher Frequenz auf und müssen bekämpft werden, wenn das Tierwohl beim Schwein verbessert werden soll. Dabei greift die alleinige Berücksichtigung des Schwanzbeißens zu kurz. Entzündungen und Nekrosen des Schwanzes treten regelmäßig auch ohne Zutun anderer Schweine auf. Der Nachweis entsprechender Veränderungen bereits zum Zeitpunkt der Geburt, das gehäuft synchrone Auftreten an so verschiedenen Körperlokalisationen wie Schwanz, Ohren, Zitzen, Klauen und anderen Partien, sowie der pathohistologische Nachweis Blutgefäß-assoziierter Veränderungen sprechen für eine primär endogene Ursache und ein Syndrom, auch wenn die Symptomatik mit Umweltfaktoren interagiert. Die Veränderungen können bei Saug- und Absatzferkeln sowie in der Mast beobachtet werden. Die Verbesserung der Umwelt kann zu erheblicher Reduktion von Entzündungen und Nekrosen führen. Gleichzeitig zeigen sich erhebliche genetische Effekte der Eber und Sauen. Der vorliegende Übersichtsartikel beleuchtet alle bislang bekannten Facetten von SINS (Swine Inflammation and Necrosis Syndrome) und gibt einen Einblick in die Eckpunkte der Pathogenese. Das Bewusstsein für ein neues und vom Schwanzbeißen abzugrenzendes Krankheitsbild soll einen Beitrag zu dessen Bekämpfung und somit zur Steigerung des Tierwohls beim Schwein leisten.

Porcine ear necrosis in weaned piglets: prevalence and impact on daily weight gain

Background

Porcine ear necrosis (PEN) in pigs is characterized by a blue to black discoloration of the tip or margin of the ear followed by necrosis. The present study investigated the prevalence of PEN in a Belgian pig farm with PEN problems in nursery pigs, the effect of a mycotoxin detoxifier added to the feed on PEN prevalence, and the impact of PEN on the piglets’ growth. Six consecutive batches of weaned piglets [565–751 piglets per batch, (n = 3898)] were included. For each weaning batch, the presence and severity of PEN during the nursery period (3–10 weeks of age) were recorded weekly. Average daily gain (ADG) was calculated by weighing 597 individual piglets divided over the six batches. Additionally different mycotoxins were measured in the feed using LC–MS/MS analysis, and to three randomly selected batches, a mycotoxin detoxifier (Mycofix® Plus 5E, Biomin) was added to the feed.

Results

At the end of the nursery period, 11.0–32.0% of the piglets in each batch were affected. The prevalence increased with the number of weeks post-weaning, especially from week 4 after weaning onwards. Mild, moderate, severe and very severe lesions represented 84.6%, 14.0%, 1.3% and 0.1% of all lesions, respectively. Different mycotoxins were present in the feed, but all at low concentrations. The mean ADG (± SD) for pigs without (n = 243) and with (n = 158) lesions was 391 g (± 71 g) and 394 g (± 65 g), respectively (P > 0.05). The ADG for mildly affected (387 g ± 68 g) and moderately affected piglets (420 g ± 44 g) was not significantly different (P > 0.05). The PEN prevalence in the batches without or with the mycotoxin detoxifier was 25% and 22%, respectively (P > 0.05).

Conclusions

Twenty-three percent of animals showed lesions at the end of the nursery. Affected pigs did not have a lower ADG compared to non-affected animals, which might be explained by the fact that most affected piglets only had mild lesions. The addition of a mycotoxin detoxifier did not influence the prevalence of PEN, possibly because of the low levels of mycotoxin contamination. Further research is warranted to assess the impact of more severe PEN lesions and the effect of control measures.