Chapter 19: Animal and Aquatic Production

Livestock production

Dairy cattle. Productivity depends on breed (for example Jersey and Friesian crosses are common in Sri Lanka), feeding, housing, health, and management. Cows need roughage (fresh grass, hay, silage), concentrates (energy and protein feed), clean water, and minerals. Housing should be well ventilated, with a dry floor and shade. Breeding uses natural service or artificial insemination; calf rearing needs colostrum in the first hours. Milk hygiene: healthy animals, clean udders, clean utensils, prompt cooling.

Poultry. Broilers are raised for meat for about six weeks; layers for eggs. Key practices: quality chicks, brooding temperature control, balanced feed, clean water, ventilation, litter management, vaccination and biosecurity (limiting visitors, disinfection, all-in/all-out systems). The feed conversion ratio (FCR) is ; if a flock eats 4.2 kg of feed per bird to gain 2.0 kg, the FCR is 2.1 (lower is better).

Goats, pigs, and other livestock suit smallholders; local goat breeds are hardy, and manure is valuable for crops.

Animal health and welfare

Healthy animals need good nutrition, clean housing, vaccination, deworming, early recognition of disease, and veterinary care. Biosecurity prevents the introduction and spread of disease. Animal welfare is guided by the Five Freedoms: freedom from hunger and thirst, from discomfort, from pain, injury, and disease, to express normal behaviour, and from fear and distress. Responsible use of antibiotics is vital to prevent resistance. Safe disposal of dead animals, manure, and waste protects people and the environment.

Aquaculture and fisheries

Aquaculture farms fish, prawns, and other aquatic organisms in ponds, tanks, and cages; common species include tilapia, carp, and shrimp, and Sri Lanka also has a significant ornamental-fish industry. Pond management: site selection (water supply, soil that holds water), pond preparation (drying, liming, fertilizing), stocking at the correct density, feeding, water-quality management, health monitoring, harvest, and handling.

Water quality is the key to success. Important parameters include dissolved oxygen (generally above about 5 mg/L), pH (about 6.5–8.5), temperature, ammonia and nitrite (toxic), alkalinity, and transparency (Boyd, 2015). Low oxygen at dawn, overfeeding, and overcrowding are common causes of fish deaths. Fish are cold-blooded, so temperature affects their feeding and growth.

Capture fisheries (marine and inland) must be managed sustainably to avoid overfishing: controls on mesh sizes, fishing seasons, and protection of breeding grounds, mangroves, and coral reefs. Post-harvest handling of fish (icing quickly, hygienic landing, cold chain) determines quality and safety.

Integrated and sustainable farming

Livestock, fish, and crops can be combined: manure feeds crops or digesters, crop residues feed animals, and pond water irrigates crops. Biogas from manure provides cooking fuel and fertilizer (Chapter 20). Such systems recycle nutrients, improve income, and reduce waste.

Common mistakes

Overstocking animals or ponds.

Neglecting biosecurity and vaccination.

Using antibiotics without veterinary advice.

Practice questions

Find the FCR if 3.6 kg of feed gives a 1.8 kg gain. [2.0]

List four water-quality parameters that matter in a fish pond.

State the Five Freedoms of animal welfare.