Cattle lameness is an important welfare concern that also has an economic impact on the dairy industry. It can be a significant problem among pasture-based herds. Our objectives were to identify cow-and herdlevel factors related to lameness and hoof lesions in dairy cows grazing year-round in Minas Gerais, Brazil. We performed a cross-sectional study in 48 pasturebased dairy herds, visiting each farm in a single visit. We evaluated 2,262 cows for mobility score (0-3) and 392 cows for hoof lesions. We used a questionnaire and checklist to capture herd management data. All information obtained was used to build multivariable models. The factors associated with lameness were low body condition score, longer time spent in the corral, being kept in paddocks during the drought period, and poor hygiene. For hoof lesions, track features were the most significant factor in determining the likelihood of heel horn erosion, white line fissure, and sole hemorrhage-by more than 3 times. Different factors related to unhygienic conditions such as leg cleanliness, frequency of cleaning, and longer time spent in the corral were associated with infectious hoof lesions. Poor human-animal relationship was related to sole hemorrhage, but patient handling of cows on the track was a protective factor against interdigital hyperplasia. The results of this study suggest that improving hygiene conditions, track features, and cow handling can improve dairy cattle mobility scores in pasture-based farms under tropical conditions. These findings also represent a first step toward planning actions aimed at decreasing lameness and hoof lesions in the studied region.

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Crossbreed F1 Holstein x Gyr cows are proving to be a good alternative for milk production under tropical conditions. In order to contribute to that affirmative, our work focused on clarifying the metabolic patter of F1 Holstein x Gyr dairy cows during the most critical time in the lactation cycle, the transition period, and to compare their performance in two seasons. Blood sampling was performed on 15 cows during summer (January to April) and on 13 cows during winter (May to August), beginning three weeks before the estimated calving date, until 30 days relative to calving. The season had a great influence on the metabolic status. Almost all evaluated metabolites, with exception for aminotransferase (AST), non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA), that have shown no variation among seasons, demonstrated a different patter between summer and winter. Liver functions were enhanced during the postpartum, with increased liver enzymes activity and increased concentration of cholesterol and BHB. Animals went through negative energy balance (NEB) and an alarming number of animals had experienced subclinical ketosis and high NEFA concentrations.

A dermatite digital (DD) é uma das principais doenças do sistema locomotor de bovinos que levam os animais à claudicação e causam graves prejuízos econômicos. Desde o seu primeiro relato na Itália, em 1974, a DD atingiu uma situação endêmica em diversos países, incluindo o Brasil. Bactérias do gênero Treponema são os principais agentes envolvidos, pois se apresentam como as bactérias mais abundantes e também estão presentes nas partes mais profundas das lesões. Mais de 20 espécies diferentes de Treponema foram identificados em amostras de DD, sendo as espécies T. pedis, T. medium, T. phagedenis, T. refringens e T. denticula as mais relatadas. Uma diversidade de outras bactérias como Mycoplasma, Fusobacterium, Porphyromonas, Bacteroides spp., Campylobacter spp., Guggenheimella spp. e D. nodosus também foram descritas. Tentativas de induzir a doença artificialmente só foram bem sucedidas com o uso de macerado de lesões ativas, demonstrando a importância do sinergismo bacteriano. Apesar da quantidade de estudos sobre o tema, a determinação da etiologia definitiva da DD permanece sendo um desafio, principalmente em relação ao papel que as diferentes bactérias encontradas desempenham no desenvolvimento da lesão. A epidemiologia desta doença também apresenta aspectos pouco esclarecidos, como os possíveis reservatórios e como ocorre a sua transmissão. Os filotipos de Treponema envolvidos na DD foram detectados na cavidade oral, rúmen, fezes e no ambiente de fazendas que possuíam a doença, porém sempre em pequenas quantidades, o que mantém em questão a importância destes locais como reservatórios.