Improving reproductive performance of Ossimi ewes using hormonal and enzymatic treatments

Abstract

The current experiment was conducted to evaluate the effect of dietary supplementation of melatonin, Zado (patent product contains cellulases, xylanases, protease and α amylase) and their combination on the reproductive performance of Ossimi ewes. Fifty-seven, multiparous, adult Ossimi ewes were randomly assigned to 4 groups, each group was fed ration supplemented with one of the following components: melatonin (G1; n = 14), Zado (G2; n = 14), melatonin and Zado (G3; n = 15) and ration with no additives (G4; control, n = 14). All ewes were fed maintenance ration for one month (during June) followed by flushing ration for 5 weeks (2 weeks before and 3 weeks after ram introduction). Melatonin (3mg/h/d) and Zado (15g/h/d) started to be added with maintenance and flushing rations, respectively. Fertile rams were introduced to ewes for 2 successive estrous cycles. General Linear Model (GLM) procedure of SAS, ANOVA and Duncan’s multiple range test were used for statistical analysis. Percentage of ewes expressed estrus was signifcantly different (P < 0.05) among the treated groups. All ewes expressed estrus in G1, while the lowest percentage (71%) was detected in G4. The interval from ram introduction to the onset of estrus differed (P < 0.01) among the treated groups. Ewes received melatonin in G1 and G3 expressed estrus earlier than ewes didn’t receive melatonin in G2 and G4. Neither body weight nor body condition score was different at the first estrus following ram introduction, while average daily gain was slightly promoted by treatments particularly with melatonin. Melatonin treated groups (G1 and G3) had significantly higher (P < 0.01) progesterone concentration than that in G2 and G4. Lambed ewes as percentage of total ewes were similar in G3 and G4 (50%), while they increased in G1 and G2 (57 and 67%, respectively). Prolificacy was greater in G1 and G3 than that in G2 and G4. Maximum prolificacy was detected in G3 while the minimum was observed in G4 (P < 0.01). Fecundity was lower (P < 0.01) in G4 (control group) than all the treated groups (G1, G2 and G3).Results of the present study indicated that melatonin could increase the estrus expression of ewes and decrease the interval to estrus after ram introduction. Thus, treatment with melatonin alone, or in combination with Zado, may provide a viable means to improve the fecundity and prolificacy of Ossimi ewes.