Age at puberty and fertility of Rahmani sheep fed on biological inoculated corn silage

Abstract

The present study aimed to investigate the effect of microbial inoculation adding to corn silage on productive and reproductive performance of sheep. The weaning male and female lambs were fed separately in four groups received a basal diet consisting of concentrate feed mixture (CFM) plus wheat straw (WS). The control group of two sex lambs (n=7 males and n=8 females) was fed R1 included CFM+WS+corn silage (CS), whereas treatment group of two sex lambs (n=7 males and 8 females) nourished R2 contained CFM+WS+ microbial inoculation corn silage (MICS). Both R1 and R2 rations were adjusted every 2weeks according feeding requirements. The measurements as body weight, body condition score, progesterone, and testosterone at puberty, semen collection at puberty. The fertility test was assayed with mature rams and ewes. The obtained results showed that the average body weight and body condition score of male and female lambs were higher (P<0.05) with R2 than R1. Both male and female lambs supplied R2 reached puberty faster and sexual hormones (testosterone and progesterone) developed earlier than lambs given R1. The ages at puberty and testosterone hormone were 32.14weeks and 3.12ng/ml for R2 lambs while 36.72weeks and 2.81ng/ml for R1 lambs, respectively. Age at puberty and progesterone concentration averaged 34.12weeks and 1.89ng/ml with female lambs presented R2, while female lambs fed R1 achieved 38.51weeks and 1.53ng/ml, respectively. Moreover, male lambs in R2 group were produced higher quality semen (P<0.05) than those in R1 group. The ram nourished R2 displayed (P<0.05) enhanced fertility 79.17% compared with R1 70.83%. The pregnancy rate and litter size with ewes received R2 were higher 91.67% and 1.30 than ewes fed R1 83.33% and 1.00, respectively. As a result, it may be concluded that addition of microbial inoculation to corm silage had positive effect on fermentation quality of silage and improved palatability and nutritive value that reflected on productive and reproductive performance of sheep.