PSIII-18 - Effect of industrial hemp supplementation on the salivary melatonin levels of angus cattle at different phase of reproductive cycle

Abstract: Melatonin is an indoleamine, a neurotransmitter and neurohormone mainly produced in pineal gland but also in the ovary. It play important role in reproduction, antioxidant, immune system and circadian behavior. Industrial hemp is increasingly being included in animal feeds and it is therefore important to evaluate the effect of industrial hemp supplementation on the profiles of melatonin following different phases of reproductive cycle. Twenty (20) apparently healthy Angus heifers, aged 19 months with average body weight of 800 lb and body condition score of 6.5 were randomly divided into two groups of ten (10) heifers each in a completely randomized design. Group 1 (n=10) were supplemented with grounded industrial hemp at 20/200mg of the concentrate and group 2 (n=10) no industrial hemp supplementation. Hay and water were provided ad-libitum. The animals were acclimatized for 1 weeks after which they were synchronized using the 7-day CO-Synch protocols. Salivary samples were collected at pre-estrus, during estrus and at post estrus. Melatonin in the saliva were assayed for using competitive ELISA kit. The salivary melatonin levels were found to be significantly higher P >0.05 in the treated groups at estrus (25.29±1.48 pg/ml), pro-estrus ( 23.98±2.3 pg/ml) and post-estrus (20.31±3.0 pg/ml) compared to the untreated groups at pre-estrus (18.9±1.5), estrus (20.4±2.22 pg/ml) and post estrus (17.22±2.6 pg/ml).The profiles of the salivary melatonin were significantly higher (P >0.05) at estrus phase in the hemp treated groups compared to the proestrus and post estrus phase of the treated groups, however, numerical but non significant increase were observed in the untreated group at estrus phase compared to the pro-estrus and post estrus phases. It was concluded that industrial hemp supplementation could improve melatonin levels and hence improve reproductive, antioxidant and immune function of the cattle.