The effect of diet type and residual feed intake on the blood and performance parameters in Kermani male lambs

The aim of this research was to study the effect of diet type and residual feed intake on the blood and performance parameters in Kermani male lambs. The first experiment was performed in a completely randomized design it involved two diet types: High-concentrated and High forage on the 40 lambs with average 3.5 months of age and body weight 16±1.5 kg for 42 days. Feed intake and body weight was measured and residual feed intake was calculated on based this data. The lambs consuming each of the diet types based on RFI value were considered in two groups RFI: low and high RFI. The effect of diet type and RFI on the blood and performance parameters in Kermani male lambs were studied in the form of factorial (2×2). According to the results, High-concentrated diet reduced dry matter intake, improved final weight, daily weight gain and feed conversion ratio (p < 0.01). The high percentage of concentrate in the diet caused increase in glucose, triglyceride, insulin, ghrelin and insulin_like factor in lamb’s blood plasma but in urea blood, concentration decrease (p < 0.01). The Low RFI groups had less feed intake and improved feed conversion ratio (p < 0.01). The concentration of glucose, urea, ghrelin, and insulin_like growth factor was lower in the blood plasma of low efficiency group than high efficiency animal (p < 0.01). Overall, the results of this study showed that RFI factor can be effective in selection of livestock with lower feed intake and better feed conversion ratio in Kermani lambs.