A certain species of ticks and biting flies attacks dairy cows, laying eggs and feeding on blood near matted fur around the neck and tail. This causes discomfort and reduces milk yield. To minimize this issue, farmers aim to breed cows with very short, sleek hair on both their neck and tail, which discourages these pests.
Suggest why biting flies and ticks are attracted to dairy cows.
Farmers cross different breeds of cattle to obtain offspring with desired phenotypic characteristics. The features of three cattle breeds are shown below:
| Breed of cattle | Coat characteristic |
|---|---|
| Hereford | short hair on the neck |
| Jersey | short hair on the tail |
| Dexter | short hair on the abdomen |
Describe how farmers could use selective breeding to develop cattle with both short hair on their neck and short hair on their tail.
Describe two differences between selective breeding (artificial selection) and natural selection.
Farmers sometimes spray chemical insecticides or parasiticides on cattle to control these pests. Give two ecological or biological disadvantages of using these chemical treatments.
