RESUMO

Hoof diseases are a major welfare and economic issue in the global dairy cattle production industry, which can be minimized through improved management and breeding practices. Optimal genetic improvement of hoof health could benefit from a deep understanding of the genetic background and biological underpinning of indicators of hoof health. Therefore, the primary objectives of this study were to perform genome-wide association studies, using imputed high-density genetic markers data from North American Holstein cattle, for 8 hoof-related traits: digital dermatitis, sole ulcer, sole hemorrhage, white line lesion, heel horn erosion, interdigital dermatitis, interdigital hyperplasia, and toe ulcer, and a hoof health index. De-regressed estimated breeding values from 25,580 Holstein animals were used as pseudo-phenotypes for the association analyses. The genomic quality control, genotype phasing, and genotype imputation were performed using the PLINK (version 1.9), Eagle (version 2.4.1), and Minimac4 software, respectively. The functional genomic analyses were performed using the GALLO R package and the DAVID platform. We identified 22, 34, 14, 22, 28, 33, 24, 43, and 15 significant markers for digital dermatitis, heel horn erosion, interdigital dermatitis, interdigital hyperplasia, sole hemorrhage, sole ulcer, toe ulcer, white line lesion disease, and the hoof health index, respectively. The significant markers were located across all autosomes, except BTA10, BTA12, BTA20, BTA26, BTA27, and BTA28. Moreover, the genomic regions identified overlap with various previously reported quantitative trait loci for exterior, health, meat and carcass, milk, production, and reproduction traits. The enrichment analyses identified 44 significant gene ontology terms. These enriched genomic regions harbor various candidate genes previously associated with bone development, metabolism, and infectious and immunological diseases. These findings indicate that hoof health traits are highly polygenic and influenced by a wide range of biological processes.

Assuntos

RESUMO

To investigate the association between locomotion score and types of hoof lesion, cows from 91 selected dairy herds in southern Chile were studied. The locomotion score was recorded for all of the lactating cows (n=10,699). The mean prevalence of lame cows, when all locomotion scores >1 were included was 33.2% in large herds and 28.7% in small herds. There were 39.7%, 42%, 17.9% and 0.4% cows with locomotion scores of 2, 3, 4 and 5, respectively. Feet (with locomotion scores representative of all severities of lameness) were examined on 676 cows from 34 large herds and 422 cows from 57 small herds. The prevalence of lesions by type ranged from 65% of cattle with at least one white line lesion to 2% of cattle with an interdigital growth. The lesions linked with increasingly poor locomotion were sole ulcer, double sole and interdigital purulent inflammation. There was correlation between claw skin lesions and also between sole ulcer and double sole within cows. It was concluded that the presence of a lesion does not imply that it is necessarily associated with increasing locomotion score. The lack of association between certain lesions and poor locomotion scores indicates either that these lesions are causing different severities of lameness, or that the case definitions used were not sufficiently precise. Locomotion score may not be sensitive enough to detect all lesions (and possibly discomfort).

Assuntos

RESUMO

Claw lameness can be associated to biomechanical factors caused by unbalanced pressure distribution under the hooves when cows are confined in modern dairy operations with hard concrete flooring. In the present study, an original claw subdivision4 was slightly modified to differentiate between the anterior (typical sole lesion spot) and posterior portions of the medial sole, and to emphasize the maximum pressures applied only on the area of contact without including the total area within these regions during midstance. The results, obtained showed significance (p < 0.044) for the interaction among Group, Leg and region (G*L*R). It was observed that the rear portion of the claws (heels) on the hind limb of untrimmed cows, are more stressed than the heel region on trimmed cows (23 % versus 16.72% of total pressure applied on the claw for untrimmed and trimmed respectively). The typical sole lesion spot pressures were increased slightly on trimmed cows as compared to untrimmed (20.20% versus 15.9%). The front feet presented differences in pressure concentration on the lateral sole between both groups (29% versus 23.25% for untrimmed versus trimmed respectively). It was concluded that, although the differences were small (5%) changes in pressure concentration, untrimmed cows stress more the sole lateral as compared to trimmed on the front feet, and on the rear feet, they stress more the heel region whereas trimmed cows tend to have a slight better balance among regions. Conversely, when cows are trimmed, the typical sole lesion spot concentrates more pressure than the heel itself (20.20% versus 16.72% respectively) and may favor the occurrence of sole ulcers.(AU)

Laminite (manqueira) pode ser associado a fatores mecânicos, causados por falta de balanceamento na distribuição de pressão na sola dos cascos de vacas confinadas em instalações modernas, que utilizam pisos de concreto. No presente estudo, a subdivisão original dos cascos de vacas leiteiras foi modificada para diferenciar-se entre a porção anterior (local típico de lesão) e posterior da sola medial dos cascos, e para enfatizar as pressões máximas aplicadas somente na área de contato não levando em consideração a área total da sola. Os resultados mostraram significância estatística (p < 0.044) para a interação entre Grupo, Pata e Região (G*L*R). Foi observado que a porção posterior (calcanhar) das patas traseiras de vacas não-casqueadas foram estressadas mais intensamente que de vacas casqueadas (23 % versus 16.72% da pressão total aplicada nas patas em não-casqueadas e casqueadas respectivamente). As pressões na região do local típico de lesão aumentaram em animais casqueados comparado com não-casqueados (20.20% versus 15.9%). As patas da frente apresentaram diferenças na concentração de pressão da sola lateral (29% versus 23.25% em não-casqueadas versus casqueadas, respectivamente). Foi concluído que, apesar das diferenças serem pequenas (5%) mudanças nas concentrações de pressão, vacas não-casqueadas estressaram mais a porção da sola lateral, comparado a vacas casqueadas nas patas da frente, enquanto nas traseiras elas estressam mais a região do calcanhar, e as vacas casqueadas tendem a ter uma distribuição melhor de pressão entre as regiões. No entanto, quando as vacas são casqueads, a região típica de lesão tende a concentrar mais pressão do que o próprio calcanhar (20.20% versus 16.72% respectivamente) podendo favorecer a incidência de úlcera de sola.(AU)

Assuntos

RESUMO

Claw lameness can be associated to biomechanical factors caused by unbalanced pressure distribution under the hooves when cows are confined in modern dairy operations with hard concrete flooring. In the present study, an original claw subdivision4 was slightly modified to differentiate between the anterior (typical sole lesion spot) and posterior portions of the medial sole, and to emphasize the maximum pressures applied only on the area of contact without including the total area within these regions during midstance. The results, obtained showed significance (p < 0.044) for the interaction among Group, Leg and region (G*L*R). It was observed that the rear portion of the claws (heels) on the hind limb of untrimmed cows, are more stressed than the heel region on trimmed cows (23 % versus 16.72% of total pressure applied on the claw for untrimmed and trimmed respectively). The typical sole lesion spot pressures were increased slightly on trimmed cows as compared to untrimmed (20.20% versus 15.9%). The front feet presented differences in pressure concentration on the lateral sole between both groups (29% versus 23.25% for untrimmed versus trimmed respectively). It was concluded that, although the differences were small (5%) changes in pressure concentration, untrimmed cows stress more the sole lateral as compared to trimmed on the front feet, and on the rear feet, they stress more the heel region whereas trimmed cows tend to have a slight better balance among regions. Conversely, when cows are trimmed, the typical sole lesion spot concentrates more pressure than the heel itself (20.20% versus 16.72% respectively) and may favor the occurrence of sole ulcers.

Laminite (manqueira) pode ser associado a fatores mecânicos, causados por falta de balanceamento na distribuição de pressão na sola dos cascos de vacas confinadas em instalações modernas, que utilizam pisos de concreto. No presente estudo, a subdivisão original dos cascos de vacas leiteiras foi modificada para diferenciar-se entre a porção anterior (local típico de lesão) e posterior da sola medial dos cascos, e para enfatizar as pressões máximas aplicadas somente na área de contato não levando em consideração a área total da sola. Os resultados mostraram significância estatística (p < 0.044) para a interação entre Grupo, Pata e Região (G*L*R). Foi observado que a porção posterior (calcanhar) das patas traseiras de vacas não-casqueadas foram estressadas mais intensamente que de vacas casqueadas (23 % versus 16.72% da pressão total aplicada nas patas em não-casqueadas e casqueadas respectivamente). As pressões na região do local típico de lesão aumentaram em animais casqueados comparado com não-casqueados (20.20% versus 15.9%). As patas da frente apresentaram diferenças na concentração de pressão da sola lateral (29% versus 23.25% em não-casqueadas versus casqueadas, respectivamente). Foi concluído que, apesar das diferenças serem pequenas (5%) mudanças nas concentrações de pressão, vacas não-casqueadas estressaram mais a porção da sola lateral, comparado a vacas casqueadas nas patas da frente, enquanto nas traseiras elas estressam mais a região do calcanhar, e as vacas casqueadas tendem a ter uma distribuição melhor de pressão entre as regiões. No entanto, quando as vacas são casqueads, a região típica de lesão tende a concentrar mais pressão do que o próprio calcanhar (20.20% versus 16.72% respectivamente) podendo favorecer a incidência de úlcera de sola.

Assuntos