Gross and microanatomical changes at the weight bearing points of ostrich induced by soil or concrete floor and implications for welfare

Abstract

This study investigated the gross and microanatomical changes occurring at the weight bearing points on the ostrich body surface induced by rearing on soil floor or on concrete floor and the implications for the welfare of the bird. Fourteen ostrich chicks aged nine weeks and raised on concrete were randomly assigned to two rearing groups of seven birds each. The birds (males and females) were raised in a pen 30m x 6m wide with either a soil or a concrete floor. All ostriches were fed a standard commercial ostrich grower diet and watered ad libitum. From week 24 two ostriches from each group were slaughtered each month. Photographic evidence and gross examination demonstrated relatively intact skin with superficial erosion of the keratinized layer at the weight bearing points of the ostriches raised on soil floor. In contrast, ostriches raised on concrete floor had observable erosion on the weight bearing points of the 24 week old ostrich. However, lesions of extreme tissue erosion involving the entire skin were observed in the heavier 36 week old ostrich raised on concrete floor. Qualitative analysis of histology slides of the collected specimens revealed extreme skin erosion deep into the subcutis of the tarso-metatarsal pads of the 36 week old ostrich raised on concrete. However, the degree of skin erosion at similar sites of ostriches raised on soil floor was superficial with the surface keratinized layer still intact. Given the well- developed planter digital cushion, the planter digital skin was not subject to excessive wearing in either group of ostriches. For the welfare of ostriches long term and continuous rearing on concrete surface should be strictly avoided as this practice obviously inflicts pain given the degree of tissue erosion observed especially on the tarsal-metatarsal pad.