Clinical characteristics of lameness and potential risk factors in intensive and semi-intensive dairy sheep flocks in Greece

Abstract

Objectives of the study were to present descriptive epidemiological characteristics of lameness in intensively and semi-intensively reared flocks of Chios-breed dairy sheep in Greece, as well as to identify potential factors that may affect development, severity and duration of the disorder. In total, 1618 ewes in nine flocks were used for assessment of locomotion score and detailed clinical examination, which were performed fortnightly throughout a milking period. Subsequently, two logistic regression models were employed to assess impact of various variables on occurrence and severity of lameness. Mean lameness incidence in the nine flocks under surveillance during the milking period was 6.8% (110 cases in 1618 ewes); between flocks range of the incidence was 0.4%-22.0%. In 48% of the cases, lameness was considered to be severe. Foot-rot was found to be the commonest lameness-causing disorder, accounting for 66% of all cases. During the investigation, incidence of lameness in relation to the causing factor was 4.5% for foot-rot, 1% for white line abscesses, 1% for white line disease, <0.5% for pedal joint abscesses and <0.5% for hoof injuries. Farm size, stocking density, parity of the ewes and lambing season were identified as significant risk factors for dairy sheep lameness occurrence. Finally, stocking density was also found to affect lameness severity.

Aetiology, Risk Factors, Diagnosis and Control of Foot-Related Lameness in Dairy Sheep

“…For molecular screening, the use of extensively polymorphic genetic markers has been suggested [57]. These markers have been identified on the chromosome 20 at the DQA2 and DQA2-like loci in the ovine Major Histocompatibility Complex (MHC-ovar) genes, which have been found to be associated with various degree of susceptibility/resistance to footrot [19,23,58] via modulation of the cellular immune response against D. nodosus [57,59,60]. It is well known in most vertebrates that the loci of MHC genes are the most polymorphic of any chromosomal region.…”

“…Among physiological factors, parity number and stage of lactation have been identified as risk factors for foot-related lameness in dairy sheep [19]. Multiparous dairy ewes are at a higher risk of developing foot-related lameness comparing to primiparous (from ca.…”

“…Multiparous dairy ewes are at a higher risk of developing foot-related lameness comparing to primiparous (from ca. 6.5 to 19.0 times), whereas, the incidence of foot-related lameness is likely higher during the first three months of lactation [19]. Increased milk yield in adult ewes during the early stages of lactation increases their nutritional and metabolic requirements; therefore, inappropriate feeding and deficiency of nutrients may lead to failure or malfunction of organs or tissues, and their inability to efficiently support functions such as keratinization of claw horn and immunological response to foot-related lameness caused by pathogens [19].…”

“…Intensive feeding, with increased consumption of concentrates (to support a high milk yield potential), may lead to subacute ruminal acidosis and laminitis. Sheep, however, seem to be more resistant compared to cows [14,19,23,40].…”

“…The majority of relevant research efforts have focused primarily on cattle [4,5,6,7,8,9,10,11], meat and wool sheep [12,13,14,15], and dairy goats [16,17], highlighting the impact of foot-related lameness on several production traits in these species [12,13,14,15]. Although relevant studies in dairy sheep are limited, recent evidence has suggested a detrimental effect of foot-related lameness on both their well-being and productive efficiency [18,19,20]. Foot-related lameness in sheep is observed in all production systems.…”