The pie-chart shows the approximate composition of cows' milk - Leaving Cert Agricultural Science - Question a - 2017

Colostrum is the first milk produced by a mother mammal (including cows) right after giving birth. It is rich in antibodies and nutrients, which help protect the young and provide essential immunity.

1. Colostrum is thicker and has a higher content of antibodies and nutrients, while ordinary milk is thinner and has fewer antibodies.

2. Colostrum is produced in the first few days after birth, whereas ordinary milk is produced after this initial period.

A farmer can ensure good milk quality by:

1. Maintaining proper hygiene during milking, including keeping equipment clean and ensuring the cow is healthy.
2. Providing a balanced diet that meets the nutritional needs of the cows to promote overall health.

Milk from cows treated for mastitis is not allowed into the human food supply because it may contain antibiotics or resistant bacteria that can pose a health risk to consumers.

One reason for culling cows on a dairy farm is to remove those that are unproductive or have health issues, which helps maintain overall herd efficiency and productivity.

A dual purpose breed refers to livestock that is raised for two primary purposes, typically for both milk production and meat production.

An example of a dual purpose breed is the Jersey breed, which is known for both its milk and meat.