Even a small amount of lead can kill cattle. Cattle will readily drink crankcase oil, lick grease from machinery and chew on lead plumbing and batteries. Other frequent causes of poisoning include flaking high lead paint, ash from fires in which lead materials were burnt, lead shot from shooting.
life cycle. 1  The series of changes in the growth and development of an organism from its beginning as an independent life form to its mature state in which offspring are produced. 2  The sequence of events between the start of one generation and the start of the next.
In organisms that reproduce sexually, the life cycle may be thought of as beginning with the fusion of reproductive cells to form a new organism. The cycle ends when that organism produces its own reproductive cells, which then begin the cycle again by undergoing fusion with other reproductive cells.