Lucky Bull (IMAGE) International Livestock Research Institute Caption Boran bull 3167, the progenitor of a line of cattle shown to be tolerant to disease caused by the Theileria parva parasite, transmitted by ticks. Credit Photo Liam Morrison/Roslin Institute Usage Restrictions Attribution non commercial share alike License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.