Studies have shown that fattening can increase the rate of residue decline by 80 per cent. However, the capacity of the animal to fatten is important in managing cattle on OC affected land. Basically young animals are easier to deal with than older ones as they have greater ability to grow and fatten thus diluting OC residues. Capacity to fatten also depends on breed type, gender, age and condition. Animal Management Bulls Bulls are very lean animals and generally do not fatten, therefore it is difficult to reduce OC residues.
Bulls are prone to digging up paddocks and are subject to contamination by ingestion of soil.
Castration has been used to decrease masculine behaviour and assist animals to fatten and dilute the level of OC residues but the best option is to keep them away from contaminated areas entirely. Production of bull beef on contaminated land is not re-commended. There is no easy method of decontaminating bulls, so they must be managed to prevent contamination. Breeding Cows Cows with suckling calves rapidly decline in pesticide residue level on clean feed. Lactation lowers residue levels markedly because OCs are excreted in the milk with the milk fat.