Correct Option: C. Prevents depletion of pasture Detailed Explanation: Zero-grazing, also known as zero-grazing systems, is a method of livestock management where animals are kept in a confined area and are fed with forage and other feed resources brought to them, rather than allowing them to graze freely on pasture. This system has several advantages, one of which is that it helps to prevent the depletion of pasture.

1. Understanding Pasture Depletion:
2. Pasture depletion occurs when livestock graze on grasslands or pastures continuously without allowing the vegetation time to recover. This can lead to overgrazing, which damages the grass, reduces its growth, and can ultimately lead to soil erosion and loss of biodiversity.
3. In a zero-grazing system, since animals are not allowed to graze on the pasture, the grass and other vegetation have the opportunity to grow and regenerate. This helps maintain a healthy ecosystem and ensures that the pasture can continue to provide feed for livestock in the long term.
4. Nutritional Management:
5. By controlling the feed that livestock receive, farmers can ensure that animals get a balanced diet, which can lead to better health and productivity. This is particularly important in areas where pasture quality may be poor or inconsistent.
6. Environmental Benefits:
7. Zero-grazing can also reduce the environmental impact of livestock farming. By preventing overgrazing, it helps maintain soil structure and fertility, reduces erosion, and can improve water retention in the soil.
8. Economic Considerations:
9. While zero-grazing may require initial investments in infrastructure (like feeding troughs and shelters), it can lead to long-term savings by reducing the need for pasture land and the costs associated with managing it.

Why Other Options Are Incorrect:

• A. Requires a lot of labour:
• While zero-grazing systems do require some labor for feeding and managing the livestock, this is not necessarily an advantage or disadvantage. The labor requirement can vary based on the scale of the operation and the management practices in place. Therefore, this option does not highlight a clear advantage of zero-grazing.
• B. Prevents livestock from physical exercises:
• This statement is true in that livestock in a zero-grazing system may not have the same level of physical activity as those that graze freely. However, this is not an advantage; rather, it can be seen as a disadvantage because physical exercise is important for the health and well-being of animals. Thus, this option does not represent a benefit of zero-grazing.
• D. Increases the cost of pasture management:
• Zero-grazing can actually reduce the costs associated with pasture management in the long run by preventing overgrazing and maintaining pasture health. While there may be initial costs for setting up a zero-grazing system, the overall management costs can be lower compared to traditional grazing systems that require constant monitoring and maintenance of pasture quality. Therefore, this option is misleading.

Summary for Revision:

• Zero-grazing prevents pasture depletion by keeping livestock confined and feeding them directly, allowing vegetation to recover.
• It promotes better nutritional management and can lead to healthier livestock.
• The system has environmental benefits, including reduced soil erosion and improved water retention.
• Other options either misrepresent the advantages of zero-grazing or highlight disadvantages that do not align with the benefits of this system.