SummaryThis study was carried out in order to determine the prevalence of lame cows, the frequency of the lesions and the degree of cow's lameness in 91 dairy farms of the X th Region in Chile. Thirty-four large dairy herds (LDH) with 10,159 (299± 57) cows and 57 small dairy herds (SDH) with 1,600 (28± 19) cows were visited once each, between August and December of 2004. During the visit the locomotion of all milking cows was observed. The degree of lameness was scored from 0 (not lame) to 4 (severe lameness). In lame cows all four feet were examined. Cow's data was recorded on individual recording sheets, being introduced as numerical variables in an Excel spread sheat, and analyzed using the statistical software Statistixs 8.0. The difference in prevalence between large and small herds and between different degrees of lameness was determined using χ 2 Test. The prevalence of lameness was 33.12% in LDH and 28.7% in SDH (P < 0.02). From the total lame cows 50.85% and 44.05% had a lameness score ≥ 2 in the LDH and SDH, respectively. The three main lesions in large farms were white line lesions (54.9%), solear haemorrhage (52.7%) and heel erosion (48.4%) while in the small farms it was the white line lesions (82.5%), heel erosion (53.3%) and solear haemorrhage (24.6%). Ninety-two percent of the lesions were found in the hind limbs, in both types of herds. It was concluded that there is a high prevalence of lameness in dairy farms of the X th Region. The prevalence and frequency of presentation of the lesions in LDH differed from those found in SDH.Palabras clave: claudicaciones, vacas lecheras. Las cojeras afectan todos los aspectos del bienestar animal, ya que, dificultan el acceso al alimento y al agua, mantienen una constante incomodidad, y el dolor causado es de larga duración, impidiendo que el animal exprese su comportamiento normal (Galindo y col 2000, Green y col 2002, Whay 2002).Diversos autores han cuantificado las pérdidas económicas producidas por las cojeras, las cuales varían de acuerdo a la patología, la disminución en producción láctea y al valor de la atención veterinaria y del litro de leche en cada país; sin embargo, todos coinciden en que estas pérdidas disminuyen la eficiencia del productor lechero (Esslemont 1990, Vermunt 1992 En Chile la información acerca de la prevalencia de problemas podales es escasa y obtenida de un pequeño 126 E FLOR, N TADICH número de rebaños. Vidal (1986) determinó una prevalencia de 46,6% de alteraciones podales en tres rebaños lecheros de la provincia de Valdivia; Escobar (1993) encontró en cinco rebaños lecheros de la VIII Región una prevalencia de 11,45%, mientras que Briceño (1997) señala que la frecuencia de animales con problemas podales en los meses de otoño e invierno era de 18,6% en dos rebaños lecheros de la Zona Central de Chile. Del Río (2003), en un estudio retrospectivo de las principales patologías podales en cinco rebaños lecheros de la Décima Región de Chile, encontró una prevalencia promedio de 33,4%. Rodríguez y col (1998) señalan que la prevalen...