CBSE Class 12 Biology Chapter 9: Strategies for Enhancement in Food Production NCERT Solutions

Solution: Animal husbandry is a vital agricultural practice that involves the scientific management and care of domestic animals like cattle, sheep, pigs, poultry, and fish. Its primary role in human welfare is to enhance the production of essential food products such as milk, meat, eggs, wool, and honey. By improving feeding practices, breeding techniques, and disease control measures, animal husbandry helps increase the yield and quality of these products. This scientific approach is crucial for meeting the growing demand for animal-derived food and materials, thereby contributing significantly to the economy and improving the livelihoods of farmers and consumers alike.

Solution: To improve both the quality and quantity of milk production on a dairy farm, several key measures would be undertaken:

1. Breed Selection: Choose high-yielding cattle breeds known for their genetic potential for milk production and disease resistance. This might involve cross-breeding or selecting breeds like Jersey or Holstein Friesian, depending on local conditions and management capabilities.
2. Proper Nutrition: Ensure a balanced and nutritious diet for the cattle. This includes providing adequate roughage (like fodder and hay), concentrates (like grains and oil cakes), and ensuring sufficient intake of proteins, vitamins, and minerals essential for milk synthesis. Water availability should also be consistent.
3. Shelter and Hygiene: Maintain clean, well-ventilated, and comfortable housing facilities that protect animals from extreme weather conditions (heat, cold, rain). Regular cleaning of the cattle and their living space is essential to prevent the spread of diseases.
4. Health Management: Implement a regular vaccination schedule and monitor animals for any signs of illness. Prompt diagnosis and treatment by a veterinary doctor are crucial. Maintaining good animal health directly impacts milk yield and quality.
5. Breeding Programs: Utilize scientific breeding techniques to improve the herd over generations, focusing on traits like high milk yield, good udder health, and disease resistance.

By systematically implementing these measures, the overall productivity and quality of milk from the dairy farm can be significantly enhanced.

Solution: A breed is defined as a group of animals within the same species that share a common set of distinct characteristics, such as general appearance, size, body shape, and other specific features. Members of the same breed are typically similar to each other and are reproductively isolated from other breeds.

The primary objectives of animal breeding are:

• Increased Yield: To enhance the production of desired products from animals, such as increasing the quantity of milk from dairy cows, meat from cattle or poultry, or wool from sheep.
• Improved Quality: To enhance the desirable qualities of the animal produce. For example, improving the protein content or fat percentage in milk, or improving the texture and flavor of meat.
• Disease Resistance: To develop varieties of animals that are more resistant to common diseases, thereby reducing losses and improving animal welfare.
• Adaptability: To breed animals that are better adapted to specific environmental conditions or management systems.

Solution: The primary methods employed in animal breeding are broadly classified into two main categories: inbreeding and outbreeding.

Inbreeding: This method involves the mating of animals that are closely related, typically within the same breed, for several generations. It helps to increase homozygosity, which can lead to the fixation of desirable traits and the elimination of undesirable ones. However, it can also lead to inbreeding depression (a reduction in vigor and fertility) if harmful recessive genes accumulate.

Outbreeding: This method involves mating animals that are less related or unrelated. It is used to overcome inbreeding depression and to introduce desirable genes from different lines or breeds. Outbreeding can be further classified into:

1. Out-crossing: Mating between animals of the same breed that have no common ancestors up to 4-5 generations. This is useful for bringing in superior animals into a herd.
2. Cross-breeding: Mating between animals of different breeds of the same species. This method aims to combine the desirable qualities of two different breeds to produce a superior hybrid offspring with enhanced traits like higher yield or better disease resistance. For example, mating a local breed with a foreign breed.
3. Interspecific Hybridization: Mating between individuals of two different species. This is a less common method and often results in infertile offspring, but can be used to combine traits from distinct species if successful.

Which method is best?

The 'best' method depends entirely on the specific goals of the breeding program. However, cross-breeding is often considered highly effective for achieving significant improvements in livestock production. This is because it allows for the combination of desirable traits from two distinct breeds, leading to hybrid vigor (heterosis) and the development of animals with superior performance in terms of yield, quality, and adaptability. For instance, crossing a local breed with a high-yielding exotic breed can result in offspring that are both well-adapted to local conditions and produce significantly more milk or meat.