Steroids in pig hair and welfare evaluation systems: combined approaches to improve management in pig breeding?

The aim of the present pilot study was to determine the allostatic load by analysing the hair cortisol and dehydroepiandrosterone­sulphate (DHEA­S) of commercial pigs belonging to different farms having good overall animal welfare according to the CREnBA (Centro di Referenza Nazionale per il Benessere Animale - Brescia, Italy) assessment protocol. The study was conducted on 86 pigs belonging to three farms with a grade higher than 8 on the CReNBA welfare evaluation system. Hair samples were taken by shaving on sows 1­10 days after weaning (Farms 1 and 2) and at the age of 8­10 months (Farm 3). The hormone concentrations were measured by radioimmunoassay. From the box plots, it is evident that the hair cortisol concentrations of animals were different between farms. Conversely, the variability of the hair DHEA­S concentration was similar between the F1 and F2 farms but much lower at F3. For all the variables considered (cortisol, DHEA­S and cortisol/DHEA­S ratio), F2 showed a higher hair concentration level than F1 (P < 0.05). The study's results indicate that the measurement of cortisol and DHEA­S in pig hair shows a different allostatic load between them, although the official welfare evaluation method assessed the farms as having good overall animal welfare.

Cortisol, DHEA, and Sexual Steroid Concentrations in Fattening Pigs' Hair.

The aim of this study was to analyze the feasibility and reliability of using hair as a matrix to determine the dehydroepiandrosterone (DHEA) and sexual steroid concentrations and the cortisol/DHEA ratio in fattening pigs. The results could be also used to plan future research to identify threshold values in order to set up strategies to control the allostatic load and increase the resilience of fattening pigs before slaughter. The study was conducted on 107 commercial crossbred rearing pigs. The hair samples were taken by shaving at the age of 36 weeks, and concentrations of the hormones were measured using a solid-phase microtiter radioimmunoassay. Females had significantly higher cortisol levels (p < 0.01), significantly lower DHEA concentrations (p < 0.05) and significantly higher cortisol/DHEA ratios (p < 0.01) than barrows. Progesterone was significantly higher in gilts than in barrows (p < 0.01). Testosterone and 17ß-estradiol were significantly higher in barrows than in gilts (p < 0.05). If future research can produce threshold values for the different markers examined, the evaluation of animals under subclinical stress conditions will be possible.