A link between damaging behaviour in pigs, sanitary conditions, and dietary protein and amino acid supply

Abstract

The tendency to reduce crude protein (CP) levels in pig diets to increase protein efficiency may increase the occurrence of damaging behaviours such as ear and tail biting, particularly for pigs kept under suboptimal health conditions. We studied, in a 2×2×2 factorial design, 576 tail-docked growing-finishing entire male pigs in 64 pens, subjected to low (LSC) vs. high sanitary conditions (HSC), and fed a normal CP (NP) vs. a low CP diet (LP, 80% of NP) ad libitum, with a basal amino acid (AA) profile or supplemented AA profile with extra threonine, tryptophan and methionine. The HSC pigs were vaccinated in the first nine weeks of life and received antibiotics at arrival at experimental farm at ten weeks, after which they were kept in a disinfected part of the farm with a strict hygiene protocol. The LSC pigs were kept on the same farm in non-disinfected pens to which manure from another pig farm was introduced fortnightly. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored for 10×10 min per pen per week. The prevalence of ear damage during the finisher phase (47 vs. 32% of pigs, P < 0.0001) and the frequency of ear biting (1.3 vs. 1.2 times per hour, P = 0.03) were increased in LSC compared with HSC pigs. This effect on ear biting was diet dependent, however, the supplemented AA profile reduced ear biting only in LSC pigs by 18% (SC × AA profile, P < 0.01). The prevalence of tail wounds was lower for pigs in LSC (13 ± 0.02) than for pigs in HSC (0.22 ± 0.03) in the grower phase (P < 0.007). Regardless of AA profile or sanitary status, LP pigs showed more ear biting (+20%, P < 0.05), tail biting (+25%, P < 0.10), belly nosing (+152%, P < 0.01), other oral manipulation directed at pen mates (+13%, P < 0.05), and aggression (+30%, P < 0.01) than NP pigs, with no effect on ear or tail damage. In conclusion, both low sanitary conditions and a reduction of dietary protein increase the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare. Attention should be paid to the impact of dietary nutrient composition on pig behaviour and welfare, particularly when pigs are kept under suboptimal (sanitary) conditions.

Assessment of Animal-Based Pig Welfare Outcomes on Farm and at the Abattoir: A Case Study

“…Prevalence of ear and tail lesions was lower than reported by Petersen et al ( 19 ) in Denmark and van Staaveren et al ( 18 ) in Ireland in finishing pigs; however, similar trends for tail lesions were found by Temple et al ( 22 ) in growing pigs in Spain. The prevalence of ear lesions on farm was higher than tail lesions, which is in agreement with van Staaveren et al ( 18 ); while van de Meer et al ( 23 ) found that ear biting was scored more frequently than tail biting behavior. The higher prevalence of tail lesions reported at the abattoir than in farm assessments seems to be due to the fact that hospital pens were not included in the on farm assessments but pigs from hospital pens could have been mixed with healthy pigs prior to transportation from farm to the abattoir.…”

Sanitary Conditions Affect the Colonic Microbiome and the Colonic and Systemic Metabolome of Female Pigs

“…They showed that the growth performance of the pigs was influenced by dietary protein supply (adequate vs. restricted). Furthermore, a link between damaging behavior, sanitary conditions, and dietary protein supply was reported, indicating that animals showed more damaging behavior under conditions of protein restriction and low sanitary status (13).…”

Effects of Three Distinct 2-Week Long Diet Strategies After Transport on Weaned Pigs' Short and Long-Term Welfare Markers, Behaviors, and Microbiota

“…Finally, tryptophan has also demonstrated consistent effects in terms of reduction of aberrant behaviors, such as tail biting (49,60), as well as changes in exploration in behavioral tests (61,62). Exploration has also been increased by high linoleic acid ratio (59) or dietary cholesterol supplementation (63,64). In the present study, pigs received three different diets: a diet including supplementary L-glutamine (GLN), a diet including an antibiotic treatment composed of chlortetracycline and tiamulin (A), and a diet without any prophylactic antibiotics or feed supplements (NA).…”

“…Besides preventing agonistic interactions from happening, an optimal ratio of fat, cholesterol and carbohydrate can even promote positive non-agonistic social interactions (52). Stress levels and fearful emotions can also be decreased with a large range of feed supplementation: vitamin E (46,53), magnesium (47), tryptophan (48,(54)(55)(56), aromatic plant extracts (53,57), chitosan (58), and the ratios of fat, cholesterol, carbohydrate (52), and linoleic acid in the diet (59). Finally, tryptophan has also demonstrated consistent effects in terms of reduction of aberrant behaviors, such as tail biting (49,60), as well as changes in exploration in behavioral tests (61,62).…”