Evaluation of coagulation and fibrinolysis in horses with atrial fibrillation

OBJECTIVE To evaluate horses with atrial fibrillation for hypercoagulability; plasma D-dimer concentrations, as a marker of a procoagulant state; and a relationship between coagulation profile results and duration of atrial fibrillation or presence of structural heart disease. DESIGN Case-control study. ANIMALS Plasma samples from 42 horses (25 with atrial fibrillation and 17 without cardiovascular or systemic disease [control group]). PROCEDURES Results of hematologic tests (ie, plasma fibrinogen and D-dimer concentrations, prothrombin and activated partial thromboplastin times, and antithrombin activity) in horses were recorded to assess coagulation and fibrinolysis. Historical and clinical variables, as associated with a hypercoagulable state in other species, were also recorded. RESULTS Horses with atrial fibrillation and control horses lacked clinical signs of hypercoagulation or thromboembolism. Compared with control horses, horses with atrial fibrillation had significantly lower antithrombin activity. No significant differences in plasma fibrinogen and D-dimer concentrations and prothrombin and activated partial thromboplastin times existed between horse groups. In horses with atrial fibrillation versus control horses, a significantly larger proportion had an abnormal plasma D-dimer concentration (10/25 vs 2/17), test results indicative of subclinical activated coagulation (18/25 vs 6/17), or abnormal coagulation test results (25/121 vs 7/85), respectively. CONCLUSIONS AND CLINICAL RELEVANCE Horses with atrial fibrillation did not have clinical evidence of a hypercoagulable state, but a higher proportion of horses with atrial fibrillation, compared with control horses, did have subclinical activated coagulation on the basis of standard coagulation test results.

Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens

With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15) using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5). Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch) and would require more exaggerated correctional movements.We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask), with and without space limitations (obstacles) and combinations thereof. Video recordings (600 Hz) and a three-axis accelerometer/gyroscope (100 Hz) were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both health categories, environmental challenges required more intense and variable movement corrections. Collectively, these results provide novel empirical support for the effectiveness of training, and highlight that overcrowding, visual constraints, and poor physical health all reduce perching performance.