Do fermented herbal extracts affect pig behavior, health and productivity? An on-farm study

Respiratory disorders and tail biting represent common issues in pig husbandry. Dietary supplementation with a combination of microbes and herbal extracts could offer welfare benefits. The aim of this study was to investigate the effect of a fermented herbal extract (FHE), a blend of fermented herbs, lactobacilli and yeasts, on behavior, aspects of health and productivity in rearing and fattening pigs. Two commercial Austrian welfare label farms, raising pigs with intact tails, were included over three batches covering all seasons. Animals were kept from weaning to slaughter in control (CON; n = 11 and 9) and treatment pens (FHE; n = 11 and 9) during rearing and fattening, respectively. Behavior as well as body, tail and ear lesions were assessed at the end of the rearing and at the middle and end of the fattening period, productivity data was measured on farm while slaughter data were additionally recorded at the abattoir. Data were analyzed using (generalized) linear mixed models. One main finding of this study was the significantly lower prevalence of the indicator "tail shorter" of FHE-fed pigs compared to control (CON) pigs at the end of rearing (FHE = 7.2 %, CON = 38.8 %; p = 0.012). The higher prevalence of intact tails in the FHE group may suggest a beneficial effect of the supplement on behavior, with a possible reduction in tail-biting activity in rearing pigs. During fattening, FHE pigs also coughed and sneezed less during behavioral observations on farm (p = 0.026). Nevertheless, slaughter findings concerning the respiratory tract did not differ. Overall, the present results suggest a potential of FHE to avert abnormal behavior and promote aspects of respiratory health in rearing and fattening pigs, which warrants further investigation.