Corticosteroid Levels in White Leghorn Hens as Affected by Handling, Laying-House Environment, and Genetic Stock

Abstract

Correlation coefficients between handling time and plasma corticosteroid concentration of White Leghorn hens were minimal when times varied from 43 to 161 sec (r = .17; P less than .05, df = 244), and no association was found when blood collection times exceeding 90 sec were omitted (r = -.02, df = 219). Handling times carried to specific endpoints of 30 and 60 sec indicated no difference, but times of 60, 120, 180, and 600 sec were associated with highly significant differences in corticosteroid levels that were inconsistent between genetic stocks. Strains selected for increased part-year egg mass responded less rapidly to handling than did unselected control strains. Confinement of hens for 4 to 6 hr in nests within their own pens caused increases of greater than 30% in corticosteroids as compared to samples obtained from hens caught directly from the floor. Neither floor pen vs. colony cage nor genetic stock differences were found for plasma corticosteroid levels of hens at a mean age of 55 weeks. Adrenocorticotropic hormone stimulation of 63-week-old hens caused an 8.5-fold increase in corticosteroids above basal but failed to elicit differential effects associated with environments or genetic stocks. Nevertheless, hens kept in floor pens had 10.8% higher survival in the laying house and exceeded colony-cage hens by more than 40% in hen-day egg mass for the final 10 weeks of a 40-week laying period.

Impact of housing technology on blood plasma corticosterone levels in laying hens

“…However, higher population density did not always result in a statistically significant rise in plasma corticosterone (Davami et al, 1987). The effect of population density on plasma corticosterone levels was not confirmed by some other studies, which report higher corticosterone levels in the plasma of laying hens kept on deep litter Cain, 1983, 1984;Craig and Craig, 1985). Although standard cage technology is considered a chronic stressor, whereas enriched technology is supposed to lack such negative effects, little information is available on changes in plasma corticosterone levels.…”

“…Blood sampling was performed randomly in hens kept in standard, enriched and deep litter technology. Utmost care was given to keep the time within 2 min between catch and conclusion of blood sampling because this small gap is known to have little or no effect on corticosterone secretion in layers (Craig and Craig, 1985).…”

Quail (Coturnixcoturnix japonica) welfare in two confinement systems

“…Quails in EA performed behavioral activities of high muscle activity demand, such as sand-bathing, which were not possible for quails in BC, and it is likely that behavioral repertoire in both treatments influenced glucocorticoid levels. Craig and Craig (1985) did not find significant differences in glucocorticoids when comparing confinement systems. Mcfarlane and Curtis (1989) considered leucocyte responses to stressful conditions as less variable than glucocorticoid responses.…”

“…The differences between treatments in RBC, PCV and hemoglobin were not part of the working hypotheses and warrant further investigation. The H:L ratio increases as stress increases and life quality decreases, indicating decreasing welfare status (Gross and Siegel, 1983;McFarlane and Curtis, 1989;Cravener et al, 1992). H:L ratio results showed that quails kept in BC experimented a lower welfare degree when compared to EA.…”

“…Mcfarlane and Curtis (1989) considered leucocyte responses to stressful conditions as less variable than glucocorticoid responses. Additionally, Cunningham et al (1988) and Craig and Craig (1985) reported that glucocorticoid levels might not be useful for chronic stress measurement. Our results corroborate the idea that H:L ratio as a more reliable markerof chronic welfare status than steroids, as in Maxwell (1993) and Shini (2003).…”