Inactivation - The destroy the activity of a substance e.g., heat treatment (56°C for 30 minutes) of serum abolishes complement activity in the serum.

Inarching - The grafting of a growing branch to a stock, without separating it from its parent stem. (Graft).

In-breeding - The mating of closely related animals (or plants), e.g., parent with offspring, brother with sister, etc., to increase the number of individuals bearing specific highly desired characteristics. The practice tends to increase the number of Homozygous gene pairs, but genetically linked undesirable characteristics arc also accumulated and progeny with such characteristics arc usually culled. (See Breed in, Cross-Breeding, Line Breeding, Out-Crossing).

Incubation - The hatching of eggs, either naturally by a hen sitting on them, or artificially by keeping them in an artificially heated Incubator. (Incubation Period).

Incubation Period - I. The period of time required for newly laid egg to develop to the stage when the young bird is ready to hatch out. For chicken eggs the period is 21 days.
2. The period between an animal becoming infected by disease-causing germs (e.g., Bacteria) and the symptoms developing, during which germ number increase dramatically.

Incubator - An apparatus used to hatch eggs by providing artificial heat, usually maintained at 37.2°C (99°P) and reduced for the last 2 days of the Incubation Period to about 36.1°C (97°P). Humidity is maintained at about 60%. Types vary from small flat ones holding 50-100 eggs, used for a small breeding flock, to large cabinet types holding up to 40,000 eggs in trays or specially designed walk-in-rooms holding up to 80,000 eggs, normally used at a Hatchery. Trays are frequently tilted to turn the eggs before they are transferred for the final 2 days of incubation to a hatching section.

Indian Game - A heavy table breed of poultry, variously coloured, including dark, white, white laced, or mottled (red, white and' black), with yellow legs, skin and flesh, and producing tinted eggs. Known for its meat quality and used in crossing. Also called Cornish.

Infectious Bovine Rhinotrachoitis - An acutely contagious viral disease affecting mainly the upper respiratory tract of cattle. Symptoms include runny eyes and nose, salivation, high temperature and loss of appetite together with a drop in milk yield in dairy cows. Fatalities are not common. The disease is more severe in store cattle.

Infectious Bronchitis - Acute, highly contagious viral disease of chicken which is characterized by respiratory symptoms like gasping and drastic reduction in egg production. It is caused by filterable virus having a particle size 0(70-106 mµ.

Infectious Disease - 'Those diseases capable of transmission from animals suffering from the disease-free animals.

Infectious Equine Encephalomyelitides - Characterized by symptoms of incoordination of movement and paraplegia. It has been caused by at least four distinct viruses which differ from each other in antigenic characters, mode of spread, verulence etc.

Infectious Laryngotrachitis - Acute, highly contagious viral disease of chickens, characterized by gasping respiration rates, sneezing and coughing which may be accompanied by expulsion of blood stained mucus from the nostrils. It has been caused by a filterable virus which can pass through a pore diameter ofO.80µ.

Infectious Necrotic Hepatitis - Acute, infectious toxaemic disease which affects affecting sheep and cattle. It is characterized by short course, blackish discolouration of the skin caused by subcutaneous uenous congestion and necrotic foci in liver. It is caused by localized bacterial infection of liver by Clostridium oedematiens.

Infectious Ovine Encephalomyelitis - Acture viral disease of sheep which is occasionally affecting horse, cattle pigs and man, characterized by fever, peculiar louping gait, convulsions and paralysis. It is caused by Russian tick born complex of the group B arbor viruses.

Infertile Soil - A soil which is deficient in plant nutrients and requires plentiful applications of fertilizer to produce good crops.

Infield - An old Scottish term for a field near the farm buildings under continuous arable cultivation and constantly manured. (Outfield).

Injurious Weeds - Certain harmful weeds (i.e., spear thistle, creeping thistle, curled dock, broad leaved dock, and ragwort) which the Ministry of Agriculture, Fisheries and Food may require an occupier to prevent from spreading, by written notice issued under the Weeds Act 1959. Also called Scheduled Weeds.

Inlay Approach Graft - Type of approach grafting to be used where the bark of the stock plant is considerably thicker than that of the scion plant.

Inoculation - Artificial introduction of micro-organisms on or into a medium, living system (e.g., animal, tissue culture). Inoculation is carried out with an aseptic technique.

Inorganic Insecticide - Insecticide of inorganic origin like arsenical or fluorine compounds; lead or calcium arsenate and paris green examples.

Insect(s) - A class of Arthropod with bodies divided into a head, thorax and abdomen, the head bearing a pair of feelers or antennae, the thorax three pairs of legs and wings. Adulthood is preceded by three stages: egg, larva and Pupa. Insects include Flies, fleas, Beetles, Aphids, Bees, etc.

Insecticide - A pesticide which kills Insects. Most of those in farm use today are synthetic organic compounds and include Chlorinated Hydrocarbons, organo-phosphorous compounds and Carbamates. They are available in granular, liquid and powder. forms and may be applied in various ways.

Inseminate - 1. To sow seed. 2. To artificially transfer Pollen to the Stigma of a plant.

Inside Bats - Poles between the Straining Poles in a Hop garden which support the Top Wire.

Insectary - Also known as insectarium. A laboratory in which insects are bred in large numbers.

Insecticide Solvent - Substances in which insecticide in the form of crystal or powder is dissolved so that it might be used as spray water commonly used; acetone, ethyl alcohol, benzene, xylene, linseed oil, groundnut oil, cotton seed oil, turpentine, kerosene, petroleum and other solvents; methylnaphthalenes superior solvents.

Intensitometer - A device which is used for determining relative x ray intensities during radiography in order to control exposure time.

Intensive Farming - A method of farming in which the aim is to produce the maximum number of crops per year, of high yield, from the amount of land available and to maintain a high Stocking Rate for livestock. (Extensive Farming).

Intensive Livestock Production - The keeping of certain livestock (e.g., beef, pigs, poultry, etc.) mainly indoors, often in relatively large numbers, with the aim of maximising efficiency by reducing per capita costs (e.g., labour, equipment, feed, etc.) and the area required. A wide variety of management system exist. Also called factory fanning. (Battery Hens, Piggeries).

Intensive Protection - Protection of crops from. pest damage to the extent that such damage is negligible and does not impede precise measurement of research parameters.

Inter Body Clearance - The diagonal distance between the bodies of a plough.

Inter-Cropping - The growing of two or more totally different species together in the same field. A common practice in developing countries which provides an insurance if one crop fails.

Inter Crops - The crops which are raised in an orchard or other widely spaced crops for increasing the income from the same piece of land by short duration crops like vegetables, pulses, papaya etc.

Interbreeding - Experimental hybridization of different species of varieties.

Inulin - Starch found in tubers and roots of artichokes, dahlias and dendelions. It is a fructosan as it is hydrolyzable to fructose. It readily dissolves in warm water and does not give any colouration with iodine.

Inverse Nitrogen - Yield Concept. According to Wilcox, the yield of a crop has been found to be inversely proportional to its nitrogen content i.e.

Where y represents the yield n represents the percentage of nitrogen in the crop and

k is a constant, the value for which was found by him to be 318b Ib/Acre.

Iodophor - An iodine containing liquid used for teat dipping to prevent the spread of Mastitis in dairy cows.

Iron Bacteria - Bacteria in the soil which secrete hydrated ferric oxide. in badly drained soils whose water contains ferrous bicarbonate in solution a condition made possible only if calcium carbonate is absent.

Irradiated Milk - Milk in which the vitamin D content is increased by irradiation by ultra violet rays.

Irradiation Breeding - Creation of mutations by subjecting the plants or seeds to radiations and their utilization for crop improvement.

Iron - (Fe). A Trace Element which, if deficient in the soil (particularly calcareous soils), can cause Deficiency Disease (Chlororis) especially in fruit crops. Also essential for Heamoglobin formation (Deficiency causes anaemia in animals) and for a variety of metabolic (Metabolism) needs in both plants and animals.

Irrigation - The application of water to soil to provide an adequate supply for crop needs, to increase crop yields or to aid their establishment. Mainly used for grass, vegetables, potatoes and sugar-beet in India. Water may be supplied by the mains, by abstraction under licence (Abstraction Licence), from a watercourse, or from on-farm reservoirs. Application is measured in inches per acre (Acre-Inch) or milimetres per hectare, the amount and frequency being related to various considerations including Soil Moisture Deficit, soil type (Light Soils contain less Readily Available Moisture than Heavy Soils), rainfall pattern and Evapotranspiration.

Irrigation Efficiency - The ratio of the amount of water used by irrigated crops to the amount actually supplied.

Irrigation Use or Water - Use of water primarily for the purpose of irrigation crops.

Irrigation Water. Water which is artificially applied in the process of irrigation. It does not include precipitation.

Isotopic Tracer - An isotope of an element, (radioactive or stable) a small amount of which may be incorporated into a sample material (the carrier) so as to follow the course of that element through a chemical, biological, or physical process, and also follow the larger sample.

Itching - Skin irritation which may occur because of chronic bowel irritation, chronic kidey diseases or a prolonged feeding of a restricted diet.