Effects of tail docking and tail biting on performance and welfare of growing-finishing pigs in a confinement housing system

Assessment of animal welfare in fattening pig farms certified in good livestock practices

Commercial swine producers are responsible for implementing changes in their production systems to ensure animal welfare. The objective of this study is to evaluate the levels of animal welfare on rearing and fattening farms certified in good animal husbandry practices using the Welfare Quality® protocol. Eighty-one certified commercial farms (n = 2,150 pigs), distributed in six geographical areas of Colombia, were evaluatedby six trained veterinarians. . A multilevel analysis was performed to identify variables associated with the animal welfare/farm rating and to identify behavioral variables. Farms evaluated had an enhanced (n = 68, 83.9%), followed by excellent (n = 7, 8.7%) and acceptable (n = 6, 7.4%) level of animal welfare. Variables significantly associated with the overall protocol rating (R2 = 0.37) were temperature comfort (OR: 1.05, p = 0.008), absence of disease (OR: 1.06, p = 0.02) and absence of pain (OR: 1.06, p = 0.0001). Significant differences in behavioral measures were observed across farms (P < 0.05). The high animal welfare scores of certified farms suggest changes in producers' understanding and attitudes towards production and animal welfare.

The Relationship between Carcass Condemnations and Tail Lesion in Swine Considering Different Production Systems and Tail Lengths

Simple Summary

Tail biting is considered a major welfare problem in swine production, associated with relevant financial costs for farmers. The European Union has reaffirmed the prohibition of tail docking practices, with all Member States establishing standards for the protection of pigs as well as measures to reduce the need for tail docking and tail biting prevalence. This research aims to assess the importance of tail lesions (using two different scores) and its influence on carcass condemnations considering different production systems and tail length. According to the results, higher tail lesion scores reflected higher total condemnations rates. An intimate association was encountered between the scarring score and total and local carcass condemnations. Tail length was also significant, with undocked animals presenting higher tail lesions scores. Organic batches reported more total condemnations. This research highlights the importance of tail lesions on carcass condemnations that may also be influenced by docking and type of production. These results suggest that scarred tail tissue should be included in the current tail surveillance program.

Abstract

Tail biting has been recognised as an intractable problem in pig production. This study aims to evaluate tail lesion occurrence in slaughtered pigs and explore the relationship between carcass condemnations and tail lesion considering different production systems and tail lengths and to evaluate the importance of creating a detailed tail score classification that includes scarred lesions. Data on a total of 9189 pigs from 73 batches with different tail lengths (undocked; docked mid-length; fully docked) and from distinct production systems (conventional; conventional antibiotic-free and organic) were collected at a Spanish abattoir. Batches with higher tail lesion scores presented a significantly higher chance of total condemnation and total condemnation due to pyaemia, being even more associated with scarring score. The within-batches probability for local condemnations and local condemnation due to abscesses increased significantly with higher scarring scores. Regarding tail length, docked at mid-length and undocked carcasses presented significantly higher odds to be condemned due to abscess. Organic farms showed a higher probability of total condemnations. This research highlights the importance of tail lesions on carcass condemnations that may also be influenced by docking and type of production. Results suggest that scarring score should be included in the tail surveillance program.

The Effects of Refilling Additional Rooting Material on Exploration Duration and Tail Damages in Rearing and Fattening Pigs

Pigs housed in commercial barns with slatted floors cannot fully perform their natural behavioral needs such as rooting or exploring. Enrichment materials can stimulate these behaviors in pigs. Here, we investigated whether exploration can be stimulated by offering additional enrichment material, i.e., chopped straw, once compared to four times daily. In two replicates each with four rearing and eight fattening pens, a total of 192 pigs with undocked tails continuously received chopped straw from a dispenser, while a stimulus to explore was given by filling the rooting area of the dispenser either once (R1) or four times (R4) daily with additional chopped straw. The dispensers were equipped with an ultra-high-frequency radio-frequency-identification (UHF-RFID) system in order to record the exploration durations of each individual pig at the dispenser. At four times throughout rearing and fattening, pigs were weighted and tail injuries and length losses were assessed. This resulted in three temporal sections within each replicate, for each of which the difference in tail length to the previous section (Δ-tail length) was calculated. Exploration durations did not change in long-term but increased from rearing throughout fattening. The refillings in which additional chopped straw was offered (R1 vs. R4) did not affect the overall exploration duration during rearing (linear mixed effects model (LME), P = 0.85) or fattening (LME, P = 0.66). However, descriptive evaluations showed that exploration durations decreased within the first 10-min sequences within the hour after refilling the rooting area with additional chopped straw in both treatments (R1 and R4). Exploration durations were affected by week, day, and hour within day during rearing (LME, all factors, P &lt; 0.0001) and fattening (LME, all factors, P &lt; 0.0001). Neither tail injuries nor length losses were affected by the refilling treatment (R1 vs. R4) during rearing (GLMM, both P &gt; 0.1) or fattening (GLMM, both P &gt; 0.1). Offering additional straw four times compared to once a day had no advantage in the present setting with regard to exploration duration and tail damages of pigs. However, refilling the rooting area with additional chopped straw triggered a short-term increase of exploration that decreased within 1 h, thus, exploration was more spread over the day.

A Systematic Review of Genomic Regions and Candidate Genes Underlying Behavioral Traits in Farmed Mammals and Their Link with Human Disorders

Simple Summary

This study is a comprehensive review of genomic regions associated with animal behavior in farmed mammals (beef and dairy cattle, pigs, and sheep) which contributes to a better understanding of the biological mechanisms influencing the target indicator trait and to gene expression studies by suggesting genes likely controlling the trait, and it will be useful in optimizing genomic predictions of breeding values incorporating biological information. Behavioral mechanisms are complex traits, genetically controlled by multiple genes spread across the whole genome. The majority of the genes identified in cattle, pigs, and sheep in association with a plethora of behavioral measurements (e.g., temperament, terrain use, milking speed, tail biting, and sucking reflex) are likely controlling stimuli reception (e.g., olfactory), internal recognition of stimuli (e.g., neuroactive ligand–receptor interaction), and body response to a stimulus (e.g., blood pressure, fatty acidy metabolism, hormone signaling, and inflammatory pathways). Six genes were commonly identified between cattle and pigs. About half of the genes for behavior identified in farmed mammals were also identified in humans for behavioral, mental, and neuronal disorders. Our findings indicate that the majority of the genes identified are likely controlling animal behavioral outcomes because their biological functions as well as potentially differing allele frequencies between two breed groups (subjectively) clustered based on their temperament characteristics.

Abstract

The main objectives of this study were to perform a systematic review of genomic regions associated with various behavioral traits in the main farmed mammals and identify key candidate genes and potential causal mutations by contrasting the frequency of polymorphisms in cattle breeds with divergent behavioral traits (based on a subjective clustering approach). A total of 687 (cattle), 1391 (pigs), and 148 (sheep) genomic regions associated with 37 (cattle), 55 (pigs), and 22 (sheep) behavioral traits were identified in the literature. In total, 383, 317, and 15 genes overlap with genomic regions identified for cattle, pigs, and sheep, respectively. Six common genes (e.g., NR3C2, PITPNM3, RERG, SPNS3, U6, and ZFAT) were found for cattle and pigs. A combined gene-set of 634 human genes was produced through identified homologous genes. A total of 313 out of 634 genes have previously been associated with behavioral, mental, and neurologic disorders (e.g., anxiety and schizophrenia) in humans. Additionally, a total of 491 candidate genes had at least one statistically significant polymorphism (p-value < 0.05). Out of those, 110 genes were defined as having polymorphic regions differing in greater than 50% of exon regions. Therefore, conserved genomic regions controlling behavior were found across farmed mammal species and humans.

Association Between Tail-Biting and Intestinal Microbiota Composition in Pigs

Tail-biting (TB) in pigs is a serious behavioral disorder. It is an important challenge in swine production as it impacts animal welfare and health and the economics and safety of the pork meat supply chain. To prevent TB, approaches including enrichment material and tail docking are proposed but none are optimal. Nutrition appears to be an important factor in TB behavior, perhaps by modulating the intestinal microbiota (IM). Our aim was to assess the association between TB behavior and IM in pigs through comparisons of IM in groups of biter, bitten and non-biter/non-bitten pigs. Each group composed of 12 pigs was formed at the beginning of the growing/finishing phase based on a target behavior analysis centered on TB behavior for the biter group and a score of damages caused to the tail for the bitten group. Blood and fecal samples were collected from each pig during a TB episode, at time 0, t0, and when the TB episode was considered finished, 4 weeks later, at time 1, t1. Serum cortisol level was determined by ELISA and used as an indicator of stress. The pig's fecal microbiota was analyzed from DNA extracted from freshly collected fecal matter using amplicon sequencing of the V4 hypervariable region of the 16S rRNA gene. Serum cortisol levels were significantly higher in either the biter or bitten pig groups compared to the negative control group (p = 0.02 and p = 0.01, respectively). The microbiota alpha-diversity was not significantly different between all groups, biter, bitten and negative control. Analyses of beta-diversity, however, revealed a significant difference between either the biter or the bitten group in comparison to the non-biter/non-bitten negative control group in terms of structure and composition of the microbiota. Lactobacillus were significantly more abundant in the negative control group compared to the two other groups (p = 0.001). No significant difference was revealed between the biter and bitten groups. Quantitative real-time PCR (qPCR) confirmed that lactobacilli were more abundant in the negative control group. Our study indicates that TB behavior is associated with the IM composition in pigs.

Utilization of Optical Flow Algorithms to Monitor Development of Tail Biting Outbreaks in Pigs

A study was conducted to evaluate activity changes in pigs associated with the development of tail-biting outbreaks using optical flow algorithms. Pigs (n = 120; initial body weight = 25 ± 2.9 kg) housed in four pens of 30 pigs were studied for 13 weeks. Outbreaks of tail biting were registered through daily observations. Behavior of pigs in each pen was video-recorded. Three one-hour video segments, representing morning, noon, and afternoon on days 10, 7, and 3 before and during the first outbreak of tail biting were scanned at 5-min intervals to estimate time budget for lying, standing, eating, drinking, pig-directed behavior, and tail biting. The same video segments were analyzed for optical flow. Mean optical flow was higher three days before and during the tail-biting outbreak, compared to 10 days before the outbreak (p < 0.05), suggesting that pigs may increase their activity three days before tail-biting outbreaks. All optical flow measures (mean, variance, skewness, and kurtosis) were correlated (all p < 0.01) with time spent standing, indicating that movement during standing may be associated with optical flow measures. These results suggest that optical flow might be a promising tool for automatically monitoring activity changes to predict tail-biting outbreaks in pigs.