Using a table or a pie-chart, show the composition of cow’s milk - Leaving Cert Agricultural Science - Question a - 2012

1. Health (disease or age of the cow)
2. Stage of lactation
3. Diet
4. Milking interval

1. Health: Diseases such as mastitis can reduce the fat and protein levels in milk. Additionally, the cow's age can affect milk composition; older cows generally produce milk with lower butterfat and protein levels due to changes in metabolism and nutrient absorption.

2. Diet: A diet high in fiber can increase the butterfat content, while a high-protein diet (e.g., leafy grass) can enhance protein levels. This variation significantly affects the overall quality of the milk produced.

1. Antibiotics
2. Bacteria (e.g., somatic cells)
3. Excess water or sediment (soil particles)

To test the hygienic quality of milk, one can conduct the following experiment:

1. Prepare two sterile test tubes with milk samples. Label one as the control and the other for testing.
2. To the test milk sample, add 1 cm³ of Resazurin (or methylene blue).
3. Incubate both samples at 37°C for 10 to 15 minutes.
4. Observe the color change: the test sample will turn from blue to pink or white if bacteria are present, indicating contamination. In contrast, the control should remain clear if uncontaminated.