Testosterone and cortisol patterns and the effects of electro-ejaculation and copulation in Awassi rams

Abstract

Abstract. The effects of month, electro-ejaculation (EE) and copulation process on testosterone and cortisol levels were investigated in Syrian Awassi rams. Jugular blood samples were collected from 10 rams at weekly intervals for 1 year. During the breeding and non-breeding season, samples were collected 60 min before EE and copulation as well as 0 (at the time of ejaculation), 20 and 60 min after EE and copulation. Low testosterone levels were detected from October to February (4.58-5.06 nmol L −1 ), while high levels were noted from May to September (8.01-11.40 nmol L −1 ) with significant differences among months (P <0.001). In contrast, cortisol levels were low from March to October (0.63-2.27 nmol L −1 ) and the highest level was recorded in December (11.30 nmol L −1 ) with a significant month effect (P <0.001). Cortisol reached its maximum concentration in the electrically stimulated rams 20 min post electro-ejaculation with no significant difference between the two seasons at this end time point. Means of testosterone levels differed between the breeding and the non-breeding season for electro-ejaculated rams. An increase in testosterone level was observed after 60 min of copulation process in the non-breeding, while no differences were noted for this hormone over the four time periods during the breeding season. Cortisol levels rose significantly in non-breeding season at 0 and 20 min after copulation (P <0.001). In conclusion, Syrian Awassi rams displayed a clear seasonality of testosterone and cortisol. Cortisol levels indicate an acute stress response to EE treatment. Females have an effect on testosterone and cortisol levels in Syrian Awassi rams only during the non-breeding season.

Effect of feeding dried olive (Olea europaea) leaves on the reproductive parameters of Awassi rams

“…Testosterone secretion in small ruminants was driven by natural day length changes or artificial photoperiodic cycles (Langford et al 1999). However, Syrian Awassi rams displayed a clear seasonality of testosterone levels where the highest level was recorded in June, while the lowest was noted in December (Alomar et al 2016). In the present study, there were no significant differences (p>0.05) in mean serum testosterone level between the two experimental groups and the Control group being 6.96, 6.85 and 8.43 nmol L -1 for Control, G1 (30%) and G2 (60), respectively, with an overall mean reaching 7.41 ± 1.08 nmolL -1 , which is close to 9.46 nmol L -1 in Syrian Awassi rams at the age of 13 months using RIA technique (Zarkawi and Al-Daker, 2016).…”

Comparative diurnal and seasonal variations of ACTH, cortisol and aldosterone in Ouled Djellal and D’Man sheep breeds reared in arid lands

“…Other endogenous factors, including androgens, significantly affect the modulation of variations in the HPA axis activity (van Lier et al 2014). Alomar et al (2016) showed previously that seasonal changes of cortisol and testosterone were opposite in the Awassi rams. In addition, androgens can act directly on steroidogenic enzymes of the adrenal cortex to suppress cortisol production (Handa et al 2013).…”

“…Other seasonal rhythms were described as well. In Syrian Awassi rams, cortisol levels were low from March to October and highest in December (Alomar et al 2016).…”

CORTISOL AS A MARKER OF PHYSIOLOGICAL STRESS IN Bos taurus SIRES

“…Сезонность выброса кортизола после электроэякуляции наблюдали у сирийских баранов породы авасси. Кортизол достигал максимальной концентрации через 20 мин после электроэякуляции без существенной разницы между двумя сезонами (60). Обнаружено повышение уровня кортизола во время возбуждения и эякуляции, а также после электроэякуляции на анестезированных животных в рутинной практике сбора семени у мясных быков (56).…”