Impacts of Chromium and Selenium-E on Cortisol Levels, Reproductive and productive Efficiency of Baladi Female Goats under Subtropical Conditions.

Abstract

The present study was conducted during estrous cycle and pregnancy period in Baladi female goats to study the effect of chromium and selenium with vitamin E on blood serum cortisol concentration. Seventy-two of mature Baladi does with age ranged from 2 to 3 years old and the mean body weight was 25.1±1.5 kg was used under two conditions of winter and summer seasons (36 animals/season). The animals were randomly divided into three groups, the 1st group was kept as control and the 2nd group was supplemented by chromium (chromium chloridetrivalent), 0.8 mg/head/day. The 3rd group was intramuscularly injected twice a week with 2ml viteselen®, contained 0.5 mg selenium and 10.7 IU vitamin E (Se-E). Serum cortisol levels were assessed in the three experimental goats during the estrous and pregnancy periods. The results demonstrated that Goats supplementation with Cr or Se-E significantly decreased (P<0.05) serum cortisol concentrations than control during estrous cycle. In addition, Cr mostly lowered (P<0.05) cortisol than control, but Se-E thoroughly increased it during pregnancy. However, under mild season at pro-estrus phase Cr treatment increased cortisol significantly (P<0.05) than control. Also, during pregnancy period Cr decreased cortisol at Mid-Pregnancy and Late-Pregnancy periods; however, Se-E increased cortisol at the Late-Pregnancy period than the control group. Under hot season, Cr treatment decreased (P<0.05) cortisol during estrous cycle, pregnancy period. However, injection of Se-E decreased cortisol during estrous cycle and showed a contrary effect during pregnancy period. On the other side, Reproductive traits of female goats showed that, under mild season conditions Cr or Se-E supplementations did not have any effect on goat’s reproductive traits, in terms of conception rate, kidding rate, fertility rate, prolificacy and fecundity compared to control group. Under hot season conditions, Cr and Se-E improved both of fertility and conception rate, as well as, increased fecundity percentage more than control. Cr group had lowest prolificacy, however; Se-E had the highest one compared to control. Chromium group had significantly (P<0.05) higher birth weight of kids than control and Se-E either at mild or hot season. However, injection of Se-E did not affect litter birth weight under mild and hot conditions.So,It can be concluded that Cr and Se-E supplementation can enhanced the reproductive and productive traits of female Baladi goats under hot season.