Genome-wide association and functional genomic analyses for various hoof health traits in North American Holstein cattle.

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.

[Morphological investigations of deep sole ulcers in cattle. Part 1: The complicated Rusterholz ulcer]. / Morphologische Untersuchungen tiefreichender Klauenerkrankungen beim Rind. Teil 1: Das komplizierte Rusterholz'sche Sohlengeschwür.

OBJECTIVE: In the context of a larger study on morphological changes of deep sole ulcers, claws with Rusterholz ulcer (RU) were investigated to describe the varied pathological changes of the RU. MATERIAL AND METHODS: Hind limbs of 55 cows displaying external signs of complicated sole ulcers were examined externally and internally. To examine the samples internally, a sagittal section was performed. Furthermore, the material was examined histologically and after bone maceration. A total of 59 claws of 112 digits with 120 deep sole ulcers displayed a complicated RU. RESULTS: The most frequent findings were: fibrosis of the heel cushion, partly in conjunction with cartilaginous/osseous areas; osteomyelitis of the tuberculum flexorium, resulting in osteolysis of the macerated bones, often together with peripheral periosteal exostoses; avulsion fracture of the tuberculum flexorium in severely deformed claws; arthritis in the distal joint, frequently in conjunction with subchondral osteomyelitis, with the macerated bone showing osteolyses near the fossae synoviales and in the periphery of the joint surface as well as periosteal exostoses on the insertion point of the joint capsule. Changes in the bursa podotrochlearis, the common digital flexor tendon sheath and the pastern joint occurred less frequently. CONCLUSIONS AND CLINICAL RELEVANCE: Fibrosis and ossification of the heel cushion were classified as metaplasia, because these processes were considered an adaption to non-physiological strain of the heel. As the infection of the RU spreads, the tuberculum flexorium may play a central role. In advanced cases, an inflammation-related weakening of the bone tissue can lead to a pathological fracture with avulsion of the deep digital flexor tendon. Secondary infection of the distal joint may occur subsequent to any avulsion of the tendon in combination with opening of the joint cavity. More frequently, the infection is likely to have expanded from the insertion point of the joint capsule to the subchondral bone to ultimately infest the joint cavity. Changes in the bursa podotrochlearis, the common digital flexor tendon sheath and the pastern joint are assumed to develop as a consequence of arthritis in the distal joint.

Surgery of the Distal Limb.

Diseases of the bovine digit remain the major cause of painful lameness in cattle and commonly constitute a diagnostic and therapeutic challenge for clinicians. Prompt surgical wound revision is critical in acute injuries. Deep infections may be treated with debridement, resection of tendons, synovioscopy, joint lavage, arthrotomy and facilitated joint ankylosis. Postoperative care is more involved, lameness persists longer, and cost of treatment is higher after salvage techniques than after amputation of the digit. Luxations and fractures of the digits often are amenable to conservative treatment but may be treated surgically if indicated.

A simple surgical treatment for bovine digital dermatitis-associated white line lesions and sole ulcers.

Non-healing white line disease (nhWLD) and sole ulcers (nhSU) are seen increasingly in herds endemically affected with bovine digital dermatitis (BDD). In 35 cows with 42 nhWLD or nhSU lesions, the healing process was monitored for up to 28 or 38 days following extensive debridement of loose horn and infected corium under regional anaesthesia, and topical application of tetracycline spray with bandaging. By 28 days, 27/42 (64%) nhWLD and nhSU were completely covered by a new horn layer and this increased to 30/42 (71%) that had healed by 38 days. Lesion sizes on day 0 correlated with clinical healing within the study period. In view of this satisfying therapeutic result, the terms nhWLD and nhSU are proposed for BDD-associated white line disease (BDD-WLD) and BDD-associated sole ulcers (BDD-SU), respectively.

Analysis of foot health records from 17 confinement dairies.

Foot health records are useful in monitoring the degree of lameness within dairy herds and, perhaps more importantly, providing insight into the underlying factors causing lameness. A database containing the incidence of foot lesions on large confinement dairy operations is largely unavailable but could prove useful to demonstrate the importance of collecting and analyzing foot lesion data to reduce lameness. Our objective was to merge foot lesion records from several dairy herds and establish a database to demonstrate how to use such data to better understand when and why foot lesions occur as an important means to manage lameness in dairy herds. The database consisted of 12 mo of records from 17 dairies (14 freestall, 1 combination dirt lot and freestall, 2 dirt lot) representing 58,155 cows from herds ranging in size from 631 to 9,355 animals in 9 states from the United States and 2 herds located in the Southern Hemisphere. Data were partitioned and analyzed as 2 separate data sets: (1) herds recording only lame events (cows lame when examined; n=8), and (2) herds recording both lame and routine trim events (n=9). Data were analyzed using PROC FREQ (SAS Institute Inc., Cary, NC) and significance was determined using Chi-square. White line disease, sole ulcer, toe ulcer, digital dermatitis, and foot rot comprised 93 and 40% (excluding routine trim with no lesion, 55%) of lesions for herds recording only lame events and those recording lame and trim events, respectively. Ratio of infectious to noninfectious lesions decreased with increasing lactation number in both data sets. Digital dermatitis and foot rot were greatest in the first 60 d in milk and differed across lactation number. Noninfectious lesions were greatest following summer heat stress, whereas infectious lesions were greatest during the coolest quarter of the year. In conclusion, analysis of the foot health data from these dairies demonstrates that (1) infectious lesions of the foot skin and soft tissues predominate in early lactation and during cooler months of the year, and (2) noninfectious lesions predominate during the 3 mo following summer heat stress and their distribution follows a typical lactation curve.

Sire predicted transmitting ability for conformation and yield traits and previous lactation incidence of foot lesions as risk factors for the incidence of foot lesions in Holstein cows.

The aims of the present study were (1) to investigate the repeatability of foot lesions [sole ulcers (SU), white line disease (WLD), and digital dermatitis (DD)] across multiple lactations, (2) to evaluate the effect of foot lesions on cow survivability and milk production across multiple lactations, and (3) to investigate the role of sire predicted transmitting ability (PTA) for conformation and production traits as risk factors for the incidence of SU, WLD, and DD. Data were collected from a dairy farm located in Cayuga County, New York. A total of 11,442 cows having first calved during the period from May 13, 2001, to March 26, 2012, were enrolled in the study. Data regarding sire genetic evaluations were obtained from DairyBulls.com (http://www.DairyBulls.com). Lameness was detected and treated and lesions were recorded into a dairy record database (DairyCOMP 305; Valley Agricultural Software, Tulare, CA) by trained farm employees. All demographic, production, and foot lesion data were extracted from DairyCOMP 305 and merged with the sires' PTA information to form a unique database. Mixed logistic regression, general linear mixed, and multivariable Cox proportional hazards models were used to analyze the data. Sole ulcers, WLD, and DD incidence was significantly higher for cows affected with SU, WLD, or DD in previous lactations. Cows affected with WLD or DD during the first lactation had significantly higher WLD or DD incidence during the second and the third lactations. Cows affected with SU or WLD during their first lactation had significantly lower milk production during the second lactation and cows diagnosed with SU, WLD, or DD during their second lactation had higher second-lactation mature-equivalent 305-d milk yield. Sire PTA for milk and protein yield were significantly associated with the incidence of SU, WLD, and DD and incidence of SU and WLD, respectively. Sire PTA for several conformation traits were found to be associated with SU, WLD, and DD incidence. Cows that were affected with SU or WLD during their first lactation were at 1.18 or 1.43 higher hazard of culling than unaffected cows, respectively. In summary, we conclude that SU, WLD, and DD are highly repeatable across lactations and that high genetic merit for milk and protein production as well as milk production (phenotype) were significantly associated with higher risk of SU, WLD, and DD. Additionally, sire PTA for several conformation traits were significantly associated with their daughters' foot lesion incidence.

Effects of trimming on dairy cattle hoof weight bearing surfaces and pressure distributions

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.

An epidemiological study of interdigital cysts in a research Beagle colony.

Interdigital cysts are chronic inflammatory lesions that can be found in dogs. In order to better understand their etiology, we completed a retrospective analysis of epidemiologic factors by using the clinical records from 743 research Beagles at our research site. Factors examined included age, gender, weight, body condition score, location of the cyst, and type of cage flooring. Statistical analysis revealed that age, body condition score, and type of flooring were all significant factors in the occurrence of interdigital cysts. The epidemiological evidence supports the hypothesis that interdigital dermatitis is the inciting cause of interdigital cysts.

Effects of caging type and animal source on the development of foot lesions in Sprague Dawley rats (Rattus norvegicus).

Retrospective analysis of data from a chronic (2-year) rat (Rattus norvegicus) carcinogenicity study was performed to compare the incidence of foot lesion development relative to cage type and animal supplier. Groups of rats from two different suppliers were housed in wire-bottom or polycarbonate cages. Clinical observations and body weights were collected. Data were analyzed to determine foot lesion occurrence, time to onset of foot lesions, and body weight change over time. Noteworthy abnormalities of the plantar surface of the hind foot (i.e., ulcers or nodular swellings) were more common in heavier rats than in lighter animals of the same sex (but different source), and abnormalities were more common in rats housed in wire cages than polycarbonate cages. However, despite differences in weight, cage type, and supplier, lesions were not found until the rats had been housed for more than 1 year.