Aim: The objective of an experiment was conducted to evaluate the effect 
of feeding bypass Methonine-Lysine on hematological and biochemical parameters 
on growing Jaffrabadi heifers of age from 12 to 18 month. Materials and 
Methods: Eighteen Jaffrabadi heifers were divided into three groups of equal 
number: control group (T1), cotton seed cake (CSC) (T2) and bypass Methionine-Lysine 
supplementation (T3). Blood samples were collected on the 1st and 63rd day of 
the trail. A close examination of the nutritive effects of treatment of CSC and 
bypass Methionine and Lysine (M-L) supplementation on hematological and 
biochemical values in the blood (white blood cell count (WBC), red blood cell 
count (RBC), hemoglobin (Hb), pack cell volume (PCV), mean corpuscular volume (MCV), 
mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), 
platelets count (PLT), total protein, albumin, globulin, blood urea nitrogen 
(BUN), creatinine and creatine kinase was carried out. 
              
              Results: BUN had a 
tendency to decrease in T2 and T3 (P<0.05) by the end of the trail with compare 
to control but no significant difference was observed between T2 and T3. No 
significant differences were found between treatments in other hematological and 
biochemical parameters like total protein, albumin, globulin, creatinine and 
creatine kinase. 
              
              Conclusion: Bypass Methionine and Lysine have no effect 
on hematological and biochemical parameters except blood urea nitrogen (BUN) in 
growing Jaffrabadi heifers. 
              
              Keywords: biochemical values, bypass 
methionine-lysine, hematological, jaffrabadi heifer.