Relationship between cortisol response to stress and behavior, immune profile, and production performance of dairy ewes

Abstract

The existence of a relationship between cortisol levels, after an acute stress, and behavioral activities, immunological profile, and production performance in sheep was studied. An initial flock of 30 Comisana ewes was involved in the experiment, and each of the 30 ewes was individually subjected to an isolation test in a novel environment. Subsequently, from the initial flock, 2 groups of 8 Comisana ewes were each retrospectively selected, and the animals were divided, according to their cortisol concentration 10 min after the isolation test, into high cortisol (HC) ewes, having a peak of cortisol concentration >90 ng/mL (average: 119.3 ng/mL +/- 11.8), and low cortisol (LC) ewes having a peak of cortisol concentration <80 ng/mL (average: 52.4+/-11.8). During the isolation test, the behavior of each animal was video-recorded and behavioral activities were registered. Blood samples were collected before the isolation test, immediately after the test (10 min), and at 60, 120, 300 min, 24 h, and 48 h after the test to evaluate percentages of T-helper (CD4(+)) and T-cytotoxic (CD8(+)) cells, CD4(+)/CD8(+) ratio, and IL-1beta and IL-6 levels. The ewes were milked for 3 d after the isolation test to determine cortisol levels and IL-1beta and IL-6 concentrations in whey. Milk yield was recorded at each milking, and milk samples were analyzed for pH, nutritional parameters, renneting properties, and somatic cell count. During the isolation test, HC ewes exhibited a shorter duration of movement and fewer bleats than LC ewes. The average plasma IL-1beta concentration was higher in HC than in LC ewes. The average whey IL-1beta and IL-6 concentrations were higher in whey from HC ewes than in LC ewes. A positive correlation emerged between plasma and whey IL-1beta concentrations. The average CD4(+)/CD8(+) ratio in blood was lower in HC than in LC ewes. Time from isolation affected the CD4(+)/CD8(+) ratio: at 120 min, the CD4(+)/CD8(+) ratio increased compared with that at 10 min after isolation and then decreased until 300 min after isolation. On average, ewes with low cortisol concentrations showed higher milk production and lower SCC than ewes with high cortisol concentrations. Results suggest that plasma cortisol concentration is connected to the behavioral response and immune competence of dairy ewes and cytokine concentrations. Both whey IL-1beta and IL-6 can be considered reliable indicators of the magnitude of hypothalamic-pituitary-adrenal axis activation. The stress-induced changes in CD4(+)/CD8(+) ratio are critical for controlling disease incidence and planning appropriate vaccination programs. High reactivity of the hypothalamic-pituitary-adrenal axis is also associated with a reduction in milk production and an increased predisposition to develop intramammary inflammatory processes.

Within-day variation and effect of acute stress on plasma and milk cortisol in lactating goats

“…Somatic cell count showed a significant increase in samples taken at 1130 h compared with 0600 h in both treatments, especially in STR, but no significant differences between treatments were observed (Figure 4). This lack of difference between treatments is in contrast to results published by Caroprese et al (2010), who observed, in an experiment in dairy ewes where animals were divided into high-cortisol and low-cortisol ewes, that SCC was higher in milk from high-cortisol ewes than in that from low-cortisol ewes. Mehdid (2009) observed that, in goats exposed to an extreme and acute stress stimulus (e.g., exposure to a dog), blood cortisol levels increased but SCC was only significantly increased in the oldest animals.…”

“…Means (±SE) of CON and STR showed small and nonsignificant differences (lactose: 4.01 ± 0.07 vs. 4.05 ± 0.07; fat: 5.14 ± 0.012 vs. 5.02 ± 0.12; caseins: 2.86 ± 0.06 vs. 2.96 ± 0.06; serum protein: 0.51 ± 0.03 vs. 0.52 ± 0.03% humid matter, respectively). The lack of effect of the interaction of sampling and treatment on these variables showed that short-term acute stress had no effect on the secretion of milk components, in agreement with the study by Caroprese et al (2010). These results, especially those obtained in the CON treatment, indicate the circadian rhythm of secretion.…”

Ovine Leukocyte Microparticles Generated by the CentriMag Ventricular Assist Device In Vitro

“…To the best of our knowledge this is the first study to describe a four color flow cytometry panel for ovine leukocytes; previous studies have used single or two-color approaches (55)(56)(57)(58). It is also the first time LMPs displaying activation markers have been shown to be generated during in vitro VAD testing, and the first time LMPs have been demonstrated in vitro using ovine blood.…”

Involução da glândula mamária durante o final da lactação e período seco de cabras Saanen: respostas de sobrevivência celular ao estresse agudo e relações com a temperatura por infravermelho

“…O estresse agudo, ou também pontual, é estabelecido quando há um pico de cortisol durante um manejo estressante de curta duração sobre o animal, e após 4 a 6 horas o cortisol retorna ao nível basal (MOEMÈDE et al, 2007;CANAES et al, 2009;. Esse tipo de estresse está relacionado à manejos rotineiros nas fazendas, como: ordenha, casqueamento, vacinação, vermifugação, transporte e entre outros (NEGRÃO, 2008;CAROPRESE et al, 2010;. Por outro lado, o estresse crônico é estabelecido pela longa exposição do animal ao meio estressante, resultando em alta concentração de cortisol e consequentemente resulta em efeitos negativos sobre a homeostasia (MOEMÈDE et al, 2007;BROWN;VOSLOO, 2017).…”

“…Consequentemente, o período de secagem é apontado como um fator estressante dentro da produção leiteira (ZOBEL et al, 2015). (CAROPRESE et al, 2010;PONCHON et al, 2017). No entanto, essas alterações parecem não serem visualizadas quando a administração de ACTH é pontual .…”