Evaluation Of Live, Postmortem And Histological Footpad Dermatitis Scores Of Commercial Turkeys And The Relationship Between Bedding, Season, Sex, Litter Characteristics And Footpad Dermatitis

Abstract

Animal welfare and efficient production are essential in the turkey industry, and this is in the best interest of every stakeholder. Footpad dermatitis (FPD), a skin inflammation frequently occurring on the footpads of turkeys worldwide, is a commonly used indicator of animal welfare. Severe FPD lesions can affect production, health, and welfare; therefore, FPD is evaluated on farms and in processing plants. This dissertation explores the agreement between live (LS) and postmortem (PS) footpad scores evaluated visually and reported moderate to strong correlations. The high sensitivity of detecting the lesions and low specificity of categorizing the normal footpads potentially indicate difficulties identifying the mild lesions. In addition to visual evaluation, a histological scoring (HS) was performed using a newly developed footpad scoring scheme accounting for injury, predominant and background inflammation, and regeneration by scoring the same footpad three times: LS, PS, and HS. Moderate to strong correlations were revealed among LS, PS, injury, and predominant inflammation scores. The LS and PS scores showed a high agreement with injury scores. The intra-rater reliability (PS, and HS) the inter-rater agreement (PS) were high. Thus, the scoring scheme was interpreted reliably. The litter moisture and poor litter conditions influence the severity and prevalence of FPD. The current dissertation explored the litter conditions and characteristics of 18 commercial turkey flocks, whether those were affected by season, sex, or bedding, and their relationship with FPD, gait scores, and flock performance indices, including mortality and BW. Bedding influenced P, K, Mn, pH, Ca, Zn, and seasonal effects were detected for P, soluble salts, ammonium-N, Ca, Mg, Zn, and litter moisture. The BW was higher for market males. Coarse particle size litter (larger than 4.76 mm, sieve size 3) correlated positively with litter moisture, and particles finer than this size correlated negatively with moisture content. The occurrence of FPD was higher for females, and flocks kept on rice hulls bedding. Footpad dermatitis scores correlated positively with total N, ammonium-N, K, Na, Ca, Mg, Zn and Cu. Coarse particle size litter correlated positively with litter moisture at the young age, however, the opposite trend was seen at the market age, possibly due to adhered litter material attached to footpads. The conclusion is that continuous monitoring of litter and footpad conditions is needed to ensure bird performance and welfare.