Agricultural Science III: Animal Husbandry, Food and Nutrition, Sustainable Agriculture, and Economics

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Importance: milk, meat, eggs, draught power, manure, and income; the potential for livestock development in Sri Lanka.
Cattle and buffalo: breeds for milk (for example Friesian, Jersey, Ayrshire, and the zebu type Sahiwal) and local breeds; buffalo breeds (such as Murrah). Management: housing, feeding (roughage and concentrates), breeding (artificial insemination, estrus detection), calf care, milking hygiene, and record keeping. Milk composition and products.
Poultry: layers and broilers; housing, feeding, lighting; vaccination programmes (for example against Newcastle disease); biosecurity; egg and meat quality.
Goats, pigs, and other livestock: breeds and management.
Animal health: common diseases (foot-and-mouth disease, mastitis, parasites), prevention (vaccination, hygiene, quarantine), and the responsible use of antibiotics. Zoonoses (such as rabies, leptospirosis, and brucellosis) link animal and human health, the principle of One Health.
Animal welfare: the five freedoms (freedom from hunger and thirst, discomfort, pain and disease, fear and distress, and freedom to express normal behaviour).
Feed and nutrition: proteins, energy, minerals, and vitamins; feed formulation.

Nutrients: carbohydrates, proteins, lipids, vitamins, minerals, water, and dietary fibre; balanced diet; energy requirements; nutritional disorders (undernutrition, micronutrient deficiencies, obesity, and non-communicable diseases).
Food quality and safety: contamination, additives, adulteration, labelling, hygiene, HACCP principles, and regulation.
Food security has four dimensions: availability, access, utilization, and stability.

Problems of conventional systems: soil degradation, overuse of agrochemicals, water pollution, loss of biodiversity, and greenhouse gas emissions.
Approaches: organic farming, integrated nutrient and pest management, conservation agriculture (minimum tillage, cover, rotation), agroforestry, permaculture, good agricultural practices (GAP), water-saving irrigation, renewable energy, and waste recycling (Gliessman, 2015).
Climate-smart agriculture: adapting to climate change, increasing productivity, and reducing emissions.
Balance: any change in farming systems should be gradual and evidence-based, supported by research, training, and markets, so that farmers' livelihoods and national food supply are protected.

Basic concepts: scarcity, choice, opportunity cost; demand and supply, equilibrium price, elasticity; agricultural products usually have inelastic demand and variable supply, so prices fluctuate.
Farm management: gross margin = total revenue − variable costs; net farm income = revenue − all costs; break-even analysis; benefit-cost ratio; cost of production; record keeping; farm planning.
Marketing: marketing channels, middlemen, value chains, grading and standardization, price information, and exports.
Institutions and policy: farmer organizations and cooperatives, credit and insurance, input subsidies, price support, extension services, land tenure, and food and trade policy.
Example: a farmer sells 3000 kg of paddy at 100 rupees per kg (revenue 300 000) with variable costs of 180 000; the gross margin is 120 000 rupees. Use figures given in the question; prices change.

CHAPTER 24