بررسي اثر طول دوره شيرخوارگي بر عملكرد خصوصيات پرواري بره هاي لري بختياري

Investigation of the effect weaning length on growth and feedlot characteristics of Lori-Bakhtiari male and female lambs

This study was conducted to investigate the effect of different length of lamb suckling on growth traits, feed conversion and feed efficiency of Lori-Bakhtiari male and female lambs. For this purpose, 66 Lori-Bakhtiari male and female lambs that were born at same season randomly selected. They were weaned at 60, 90 and 120 days of age and put in a 6 month feedlot period. A completely random design with factorial method (sex and weaning age) was used. Diets for male and female Iambs were isocaloric (2.51 M.EMcal/kg DM) and isonitrogenous (13.07% CP on DM basis). This diet contents 40 percent forage and 60 percent concentrate. The results had showed that there were significant differences between weights was lower for 60 days weaning age (P<0.05). The means of final weight groups were 44.64, 43.01 and 41.30, 1.09 kg. for 60, 90 and 120 days of weaning ages respectively and was significantly higher for 60 days weaning age group (P<0.05). Average daily gain was significantly higher (275.18 g) for male Iambs than female Iambs (210.74 g) (P<0.01). Interaction effects between weaning length and final weight and daily gain male and female lamb were significant (P<0.05). The mean of feed conversion and feed efficiency in differences groups were not significant, but between male and female Iambs were significant (P<0.05). It is recommended that, Lori-Bakhtiari male lambs can be weaned at 60 days and put in a 6-months feedlot period.