Prevalence and Risk Factors Associated with Rib Lesions in Dairy Cows.

Unilateral or bilateral hard bony enlargement is sometimes palpated over dairy cows' ribs. Although usually not painful, these injuries may have welfare and economic implications and can be used as indicators of poor husbandry conditions. The objective of this study was to determine the prevalence of rib lesions in dairy cows kept in intensive systems and to identify the risk factors either associated with the housing or with the animal's clinical history. We examined the ribs of all 1319 lactating cows from 22 Portuguese dairy farms. In each farm, housing and animal potential risk factors were recorded. Additionally, clinical examination, including lameness scoring, was performed on all cows showing rib lesions. The global rib lesions' prevalence per farm was 2.3%, ranging from 0% (n = 12 farms) to 6.1% (n = 1 farm). Lesions were found in cows with an average of 3.7 lactations. The main farm risk factors were narrow stalls; insufficient feeding places; insufficient cubicles; and the presence of an exposed curb at the back end of the stalls. Rib lesions were associated with a history of lameness but not with lame cows at the moment of examination or a history of being a downer cow. In conclusion, rib lesions' prevalence can be high in some farms, being significantly associated with cubicle design and lameness. By being associated with chronic lameness and inadequate housing, rib lesions should be included in dairy cows' welfare assessment protocols.