A study based on records taken at time of hoof trimming reveals a strong association between the IQ motif-containing GTPase-activating protein 1 (IQGAP1) gene and sole hemorrhage in Holstein cattle.

Feet and leg problems have a major effect on the well-being and lifespan of the dairy cow and thus are economically important to the dairy farmer. Apart from approaches using genetic selection for classical traits from conformation scoring, attempts for genetic improvement can be based either on records of individual disease cases or on records of disorder status at time of hoof trimming. In this study, 1,962 first-lactation cows were subjected to hoof trimming with an assessment of disorder status for sole hemorrhage as a binary trait. Cows were from 7 large commercial herds in Mecklenburg-Western Pomerania (northeastern Germany) that had similar housing with cubicles, slatted flooring, little use of straw for bedding, and total mixed ration feeding. Cows were trimmed and assessed once, focusing on cows in the first half of the lactation. Herds were visited at intervals to enable recording of cohorts at a similar stage of lactation. Each cohort or herd-visit included between 31 and 165 cows. Additional measurements included body weight, back fat thickness, and body condition at time of trimming. Further data on dairy production, conformation scores, and reproductive performance were merged after collection of records had finished. The DNA extracted from blood of 1,183 cows was used for analysis with a custom-made array of 384 single nucleotide polymorphisms (SNP). The SNP were selected according to results from the literature for effects in classical conformation traits, from biochemical pathway analysis, and from comparative analysis of putative candidate genes in cattle, pigs, and sheep. Selection of cohorts of cows for SNP chip analysis was such that cohorts with extreme frequencies of disorders and cohorts with slightly deviating housing systems were excluded in this first step. The results from a mixed threshold model analysis with genotype included as a fixed effect and accounting for relationships among animals revealed that the intronic SNP rs29017173 (A/G) within the IQ motif-containing GTPase-activating protein 1 (IQGAP1, Bos taurus autosome 21) was significantly associated with disorder status. Back-transformed means of disorder status for the 3 genotypes were 0.37 (AA), 0.52 (AG), and 0.56 (GG). Using the full data set of 1,962 cows, including the less-suitable cohorts, gave back-transformed means of 0.51 (AA), 0.58 (AG), and 0.62 (GG). As SNP rs29017173 is included on the Illumina BovineSNP50 DNA Analysis BeadChip (Illumina Inc., San Diego, CA), a sample of 2,394 artificial insemination sires from the German calibration sample for genomic selection from birth years 1998 to 2003 was studied for possible correlated effects. The A/G polymorphism of SNP rs29017173 studied here was also associated with substantial effects for feet and leg traits from the classical conformation score system. Selection using this polymorphism will be facilitated by the fact that the same allele is favored for all traits with substantial effects.

Relationships between bovine hoof disorders, body condition traits, and test-day yields.

A designed field study was conducted on 1,962 first-lactation Holstein cows kept on 7 large-scale dairy farms in Germany, in loose-housing systems on standard slatted flooring. Records of hoof disorders at trimming composed of subclinical as well as clinical cases were combined with body measurements and body condition scores, test-day records, and further individual cow data. The 6 most frequent disorders were laminitis, also known as sole hemorrhage (57.3% of all cows), dermatitis digitalis (17.0%), dermatitis interdigitalis (7.9%), white line disease (12.6%), sole ulcer (7.1%), and interdigital hyperplasia (5.5%). The most important environmental effects were herd-visit date and stage of lactation. Heifers between 50 and 99 d in milk had the highest frequencies for laminitis. Lighter cows were less susceptible to laminitis and white line disease, but had a higher prevalence of interdigital hyperplasia. Relationships between stature and white line disease as well as relationships between body condition score and dermatitis digitalis were nonlinear, resulting in an improved disorder status of cows with an intermediate condition score and average stature. Increased biomechanical stress caused by different factors (weight, social rank, standing time) is a presumed effect that leads to an increased susceptibility for hoof diseases. From a management perspective, under- and overconditioning should be avoided. Milk production traits differed between cows with and without laminitis-related claw horn lesions. Fat percentage and fat-to-protein ratio in the first month before trimming were significantly decreased for cows with a positive laminitis status. Hence, this finding points to metabolic disorders being associated with a higher risk for hoof diseases. Estimates of heritabilities for laminitis, dermatitis digitalis, dermatitis interdigitalis, white line disease, and sole ulcer were 0.09, 0.14, 0.10, 0.11, and 0.06 when applying a threshold model with a probit link function.

Reduction of infarct size by intravenous injection of uncultured adipose derived stromal cells in a rat model is dependent on the time point of application.

Stem cell therapy is a promising tool to improve outcome after acute myocardial infarction (AMI), but needs to be optimized since results from clinical applications remain ambiguous. A potent source of stem cells is the stromal vascular fraction of adipose tissue (SVF), which contains high numbers of adipose derived stem cells (ASC). We hypothesized that: 1) intravenous injection can be used to apply stem cells to the heart. 2) Uncultured SVF cells are easier and safer when cultured ASCs. 3) Transplantation after the acute inflammation period of AMI is favorable over early injection. For this, AMI was induced in rats by 40min of coronary occlusion. One or seven days after AMI, rats were intravenously injected with vehicle, 5×10(6) uncultured rat SVF cells or 1×10(6) rat ASCs. Rats were analyzed 35 days after AMI. Intravenous delivery of both fresh SVF cells and cultured ASCs 7 days after AMI significantly reduced infarct size compared to vehicle. Similar numbers of stem cells were found in the heart, after treatment with fresh SVF cells and cultured ASCs. Importantly, no adverse effects were found after injection of SVF cells. Using cultured ASCs, however, 3 animals had shortness of breath, and one animal died during injection. In contrast to application at 7 days post AMI, injection of SVF cells 1 day post AMI resulted in a small but non-significant infarct reduction (p=0.35). Taken together, intravenous injection of uncultured SVF cells subsequent to the acute inflammation period, is a promising stem cell therapy for AMI.