Effect of age and sex of animal on the antibiotic residues in tissues of some slaughtered animals

A total of 200 carcasses representing 600 samples (200 muscles, 200 livers and 200 kidneys) were obtained randomly from bovine carcasses (cattle and buffaloe) at Mansoura abattoir in Dakahlia Province, Egypt and were examined for the presence of antibiotiPositive carcasses distributed according to species into 5 (3.57%) cattle and 5 (8.33%) buffaloes, while according to sex they distributed into 5 (2.77%) males and 5 (25%) females, also they distributed according to age into 4 (5%) young animals with temphad detectable levels of oxytetracycline residues, from which 5 (0.83%) had oxytetracycline residues at violative levels above the maximum residue limits (MRLs) while the other 3 (0.5%) had levels below (MRLs).Experimental study indicated the withdrawal time of oxytetracycline in broilers as follow: 6 days in breast and thigh muscles- 8 days in liver- 9 days in kidney after intramuscular injection of drug in the thigh muscle in a dose of 20 mg/kg B. W for