Evaluation of stress status using the stress map for guide dog candidates in the training stage using variations in the serum cortisol with nerve growth factor and magnesium ions

Fur Cortisol in French Bulldogs with Different Manifestations of Brachycephalic Obstructive Airway Syndrome

In the present study, 33 French bulldogs with varying degrees of brachycephalic obstructive airway syndrome (BOAS) were evaluated for various parameters to provide evidence of chronic stress in the dogs. For this purpose, an owner interview, a clinical examination, and cortisol concentrations in the fur of the dogs were collected. The median cortisol concentration in the fur of the dogs suffering from BOAS (n = 19) was 0.99 pg/mg (range 0.63-66.18), while that of the control group (n = 14) was 1.13 pg/mg (range 0.3-43.45). However, the statistical analysis did not reveal a statistically significant difference; therefore, it is not possible to distinguish between dogs clinically affected with BOAS and those without clinically relevant signs of the disease. There was no statistically significant difference between the age of the animals and the fur cortisol. None of the owners in the examination and control groups indicated that their dog was suffering from chronic stress which shows that the disease is easily underestimated and remains common. Thus, a thorough clinical examination by an experienced veterinarian remains the gold standard in order to diagnose BOAS.

Salivary Cortisol in Guide Dogs

Guide dogs work for extended periods and are exposed to multiple environmental stimuli that could lead to higher stress compared with companion dogs. Cortisol is the main hormone associated with stress in most mammals. This study included seven guide dogs and seven same-breed dogs that were trained as guide dogs but became companion dogs to compare their salivary cortisol levels before, during, and after a period of social isolation and exposure to a 110-decibel gunshot sound. Each dog was left alone in an empty room for 60 min. After 15 min, the dogs were exposed to the sound. We collected four saliva samples from each dog. The first one was taken 5 min before starting the social isolation period, and the following ones at 15, 30, and 45 min after the test started. A two-way ANOVA was used to compare the group effect and the time effect during isolation and noise exposure. The results showed higher levels of cortisol in the guide dogs compared with the companion dogs throughout the test. No differences were found in time or in the interaction between time and group. This suggests that being a guide dog increases levels of basal cortisol when compared with dogs that live as companion animals and family members.

Serum nerve growth factor in horses with osteoarthritis-associated lameness

BACKGROUND

Nerve growth factor (NGF) is a neurotrophin that is increased in osteoarthritic joints of horses. In humans, NGF has been associated with pain, and both synovial and serum NGF concentrations are increased in osteoarthritic patients. Studies in humans also have shown that serum NGF concentration can increase with stress. Serum NGF concentration should be evaluated in horses with osteoarthritis-associated lameness.

OBJECTIVES

Quantify and compare serum NGF concentration in horses with osteoarthritis-associated lameness and sound horses. Additionally, the impact of short-term stress on serum NGF concentration was investigated.

ANIMALS

Lame horses with radiographic evidence of osteoarthritis (n = 20), lame horses without radiographic changes in the affected joint (n = 20) and sound horses (n = 20). In addition, horses with acute fractures (n = 9) were sampled. To determine the effect of stress, serum from horses subjected to a stressful event (transportation, n = 5; stress confirmed by increased serum cortisol concentration) was analyzed.

METHODS

Cross-sectional clinical study (lame, sound, and fracture cohorts) and experimental longitudinal study (stress cohort). Serum NGF concentration was determined using a quantitative sandwich ELISA.

RESULTS

Serum NGF concentration was increased in lame horses with radiographic evidence of osteoarthritis (P < .0001; median, 238 pg/mL; interquartile range [IQR], 63-945 pg/mL) and in lame horses without radiographic evidence of osteoarthritis in the painful joint (P < .05; median, 31 pg/mL; IQR, 31-95 pg/mL) compared with sound horses (median, 31 pg/mL; IQR, 31-46 pg/mL). Serum NGF concentration did not increase with short-term stress and was low in horses with fracture-associated pain.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum NGF concentration was high in the cohort with advanced osteoarthritis and should be investigated as a marker for osteoarthritis-associated pain.