Studies indicate that the evaluation of animal welfare in birds may be carried out with the measurement of the stress-related hormone corticosterone in feathers. However a standardized procedure for corticosterone measurements in feathers is lacking, a validation needs to be carried out for each new species before implementation. The aim of the present study was to establish a valid method to measure corticosterone concentrations in feathers of laying hens in a precise and repeatable manner using an established and commercially available ELISA. Validation was performed with feather pools of tail and interscapular feathers of commercial Lohmann Brown laying hens. Assessment groups, consisting of 5 replicates, were created. All replicates of an assessment group were processed at the same time. Each replicate was run in 4 repetitions by ELISA. Intra-assay and interassay CV was 7.5 and 6.4%, respectively. The serial dilution showed linearity and parallelism. Examining the hormone extraction efficiency by using different methanol volumes resulted in no statistical differences ( P > 0.05). Pulverized feathers showed higher corticosterone values than minced feathers ( P > 0.05). Differences were shown between 2 feather types (tail vs. interscapular feathers; P < 0.05), as well as between vane and rachis ( P < 0.05). Performance of a freeze–thaw cycle led to a decrease of corticosterone concentrations in the samples. A possible effect of UV-A radiation on the stability of corticosterone in the feathers was not found ( P > 0.05). With the present study, a valid protocol, feasible for analyzing feather pools of laying hens, was developed. It may provide fundamentals for further investigations on corticosterone in feathers as a noninvasive indicator to evaluate aspects of animal welfare.

The prevalence of intramammary infections (IMI) and subclinical mastitis (SCM) in 436 German Holstein heifers was put in relation with clinical findings of the udder and data regarding individual rearing and housing conditions of the animals. The clinical examination took place on the day of the livestock auction (at approximately 41 d in milk, DIM). On that day, 31% of the heifers had IMI in at least one quarter, and 18% of all quarters were infected. Coagulase-negative staphylococci were the most prevalent bacteria isolated, accounting for 68% of the positive samples. Data were analysed by logistic regression. Criteria such as 'juvenile intersucking', 'teats shorter than 35 mm', 'teats with a diameter <18 mm' and 'udder oedema at the day of the auction' were associated with IMI in heifers during the first 41 DIM. Loose-housing systems during pregnancy (as opposed to tie-stalls), juvenile intersucking, clinical mastitis during the first week after calving, teat diameters <18 mm, and employing organic bedding material in the stables before calving were associated with subclinical mastitis.

Currently, there is no consistent approach to on-farm and post-mortem foot pad (FP) assessment in turkey husbandry in sampling of both feet, sample sizes of birds and scoring schemes during the production period. Therefore, in a field study, 11,400 turkeys, i.e., 22,800 feet, were macroscopically scored at 4-week intervals, 60 birds per flock per date, in accordance with the scale system of Hocking et al. ( 1 ). Spearman's rho was calculated between the foot pad dermatitis (FPD) score of both feet of an individual turkey. Sample size for FPD monitoring was calculated for several flock sizes, considering expected FPD prevalence and the error and confidence level (α = 0.01, 0.05, 0.1). To compare macroscopic to histological findings, ten excised FPs were histopathologically investigated by hematoxylin & eosin staining. To align manual macroscopic FPD evaluations with a technical system, 20 photographic images of FPD were measured using the ImageJ program. The scores of both feet of an individual turkey correlated between r = 0.252 and r = 1.000. Thus, both feet of a bird should be monitored, while the worse foot should be evaluated. As an exemplary sample size for on-farm FPD assessment, 77 turkey poults were calculated in a flock of 4,000 birds with an expected FPD prevalence of 40% and α = 0.1. The sample size of monitored birds within a flock should differ and depend on flock size and expected FPD prevalence. Histopathological findings showed normal and non-affected structures of a macroscopic Score 0 and a moderate ulcer of the macroscopic Score 1 and Score 2. The applied assessment scheme should distinguish first alterations and scar tissue as separate scores to differentiate the need for management intervention vs. the success of management measures that were already implemented. FPD affected areas were given lower Scores and assessed to be healthier when evaluated by an image system, compared to a manual assessment. Furthermore, with regard to an increase in camera-based assessments, the boundary of the metatarsal pad needs to be clarified. In conclusion, a new scoring system is required, as the size of the FP cannot be clearly defined and different tissue textures, as well as valid sample sizes are not currently sufficiently considered.

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