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.

Effect of stress during slaughter on carcass characteristics and meat quality in tropical beef cattle.

OBJECTIVE: This study aimed to determine the effects of stress during slaughter of beef cattle on physiological parameters, carcass, and meat quality at a Federal Inspection Type slaughterhouse located in the southeast of Mexico. METHODS: A total of 448 carcasses of male Zebu×European steers with an average age of 36 months were included. Carcass assessment of presence of bruises and bruise characteristics was carried out on each half-carcass. Blood variable indicators of stress (packed cell volume, neutrophil to lymphocyte ratio, glucose, cortisol concentration) and meat quality parameters (pH, color, shear force, drip loss) were evaluated. RESULTS: Of the 448 carcasses evaluated, 81% of the carcasses showed at least one bruise; one bruise was detected in 36.6% and two bruises in 27.0% of animals. Of the 775 bruises found, 69.2% of the bruises were grade 1 in region 3. Of the 448 carcasses studied, 69.6% showed hyperglycemia (6.91 mmol/L); 44.3% and 22.7% showed high (74.7 ng/mL) and extremely high (108.8 ng/mL) cortisol levels, respectively, indicative of inadequate handling of animals during preslaughter and slaughter. Of the carcasses evaluated, 90.4% had a pH ≥5.8 with an average of pH 6.3. In both pH groups, meat samples showed L* values >37.0 (81.6%) and a shear force >54.3 N; meat pH≥5.8 group showed a drip loss of 2.5%. These findings were indicative of dark, firm, and dry (DFD) meat. According to principal component analysis, grades 1 and 2 bruises in region 3 and grade 1 bruises in region 5 were highly associated with cortisol, drip loss, and color parameters b* and h* and were negatively associated with L*, a*, and C*. CONCLUSION: The bruises probably caused by stress-inducing situations triggered DFD meat. Appropriate changes in handling routines in operating conditions should be made to minimize stress to animals during the slaughter process to improve animal welfare and meat quality.

Progesterone and estradiol profiles in different reproductive stages of captive collared peccary (Pecari tajacu) females assessed by fecal metabolites.

The study determined the fecal progesterone and estradiol profiles in different reproductive stages of captive collared peccary (Pecari tajacu) females from eastern Mexico. Fifteen adult females were included. At the start of the study the females were either pregnant (early, mid, or late pregnancy), lactating, or non-lactating of unknown pregnancy status. Feces from each female were collected once a week during nine consecutive months to determine concentrations of fecal progesterone and estradiol metabolites using ELISA. Progesterone was similar in early (2048±285ng/g), mid (2254±274ng/g), and late pregnancy (2491±374ng/g), and in early-pregnant and non-lactating females (1154±274ng/g). Progesterone in lactating females (442±255ng/g) was lower than in females at any stage of pregnancy, but was similar to non-lactating females. Overall progesterone in pregnant females (2229±173ng/g) was higher than in lactating and non-lactating females together (772±189ng/g). Estradiol was similar in early (66±8ng/g), mid (83±9ng/g), late pregnant (109±15ng/g), and non-lactating females (64±9ng/g). Estradiol in lactating females (34±8ng/g) was similar to estradiol in early-pregnant and non-lactating females, but was lower than in females in late and mid pregnancy. Overall estradiol in pregnant females (79±6ng/g) was similar to non-lactating females, but higher than in lactating females. The progesterone and estradiol profiles of captive collared peccary females at different reproductive stages were determined by assessing concentrations of fecal hormone metabolites.

Faecal cortisol concentrations as indicator of stress during intensive fattening of beef cattle in a humid tropical environment.

The study evaluated the concentrations of faecal cortisol metabolites (FCM) in intensively fattened beef cattle from a feedlot in a humid tropical environment. A total of 360 bulls weighing 271-371 kg were kept confined in pens from the start to the end of the fattening period (FP). At 24 h after arriving at the feedlot, cattle were distributed into the pens according to their live weight: 271-320 kg, 321-370 kg, and >370 kg. At the start of the FP, four pens of each weight group were randomly selected, and in each of them 10 faecal samples were obtained from 10 randomly selected bulls; this sampling was repeated in the same pens and in each weight group at the middle and end of the FP. The FCM were measured through enzyme immunoassay. The 271-320 kg group had higher FCM at the end of the FP (P < 0.05), the 321-370 kg group had similar FCM throughout the FP (P > 0.05), and the >370 kg group showed higher FCM at the start and end of the FP (P < 0.05). Higher FCM were observed at the middle of the FP in the 321-370 kg group, and at the end of the FP in the 271-320 kg and >370 kg groups (P < 0.05). Mean FCM obtained throughout the FP were within normal ranges for cattle, suggesting that appropriate management in feedlots in humid-tropical regions can provide bulls with a low-stress environment.