Agricultural science

• Types of rations


  • Maintenance ration
  • Production ration
• Maintenance ration


  The amount of food needed to prevent loss or increase in live weight of the animal. It is just sufficient to maintain the supply of energy and protein for all metabolic activities.
• Production ration


  Any mixture of foods that is supplied in excess of maintenance for meat, milk or egg production.
• Flushing-feeding production ration


  Used to increase the fertility rate of the female, e.g., sow/gilt, ewe.
• Steaming up feeding production


  Given during the late stages of pregnancy to increase the mammary tissues and blood supply
• Balanced diet


  One that contains all the food nutrients in the right proportion for growth and production.
• When dealing with the nutrients of farm animals, one must consider the following:
• Factors to consider when dealing with farm animal nutrients


  • Foods vary in their nutrients composition
  • The purpose for which the animal is kept
  • The age of the animal
  • The type of animal, ruminant vs. non-ruminant
  • The type of management system, intensive vs. extensive
• Main parts of the ruminant's stomach


  • Rumen
  • Reticulum
  • Omasum
  • Abomasum
• Rumen


  • Acts as a strong organ
  • Receives the grass and other herbage taken in by the animal
  • Cellulose-digesting bacteria break down the cellulose in the grass
• Reticulum


  • Forms semi-liquid grass into boluses/cuds
  • Pumps cuds/boluses back up to the mouth through anti-peristalsis/regurgitation
  • Acts as a strainer to remove foreign materials
  • Returns large particles of food back to the mouth
• Omasum


  • Receives the masticated cuds from the mouth
  • Squeezes liquids out of the cuds
  • Breaks down fats, to be absorbed as fatty acids and glycerol
  • Passes the remains to the duodenum
• Abomasum


  • Produces gastric juices
  • Pepsin breaks down proteins into amino acids
  • Rennin coagulates milk
• Examples of ruminant animals include: cattle, goat, sheep, deer, elk, giraffe, and camels.
• The cow swallows its food without chewing. It enters the rumen.
• Sometimes a non-ruminant animal, e.g., Pig is fed grass.
• Pigs have a simple, one-compartment stomach not designed to cope with large quantities of grass.
• Grass has a high percentage of cellulose which cannot be broken down by the digestive juices produced in the stomach of the pig.
• Disc plough


  • One unit consists of two or more rotating discs
  • Mounted on a frame called the disc standard which is attached to a cylindrical beam to which weights are added to aid in penetration of the soil
  • Has a furrow wheel at the rear which keeps in touch with the soil
  • The disc is forced into the ground by added weight and by the suction of the disc due to the angle at which it is set
• Rotary plough (Rotovator)


  • Consists of a horizontal shaft on which tyres are bolted
  • The horizontal power driven shaft usually operates at about 300 rpm
  • Considered a secondary tillage implement
  • Used on newly ploughed land to produce a fine tilth and penetrates to a depth of 10-15 cm
  • A rotary cultivator is used to prepare a seedbed in one operation, i.e., ploughing, cultivating, and harrowing, if the soil is light
• To improve his standard of living, the farmer must increase his production and productivity.
• One of the best ways is by the introduction of machinery.
• Factors to consider before introducing machinery

  • The initial cost of the equipment
  • Annual cost of operating the equipment
  • The year-round use of the equipment
  • Lifespan of the equipment
  • Running cost (or maintenance cost) of the equipment
  • Adaptability of the equipment
  • Technical efficiency of the equipment
  • Availability of spare parts for the equipment
  • Size of holding to be used in production
  • Qualified service personnel
• Tractors


  • The most versatile source of power
  • Transmits power in four ways: 3 points linkage-pull plough, Power Take Off (PT.O.) shaft, By pulleys and belts, Large tractors are fitted with hydraulic arms so that they can be linked with the hydraulic systems of other implements
• Types of tractors


  • Wheel Tractor
  • Crawler or Track Tractor
• Types of wheel tractors


  • Hand guided, two wheel tractor
  • Four wheel, two wheel driven (single axle)
  • Four wheel, four wheel driven (double axle)
• Hand guided, two wheel tractor


  • The cheapest of all tractors
  • Maintenance cost is low
• Shoot system


  Composed of erect stems on which are attached leaves, flowers, and buds
• Nodes


  Regions where leaves are attached to the stem
• Internodes


  Sections of stem between nodes
• Leaf axil


  The upper angle between the stem and the leaf at the node
• Axillary (lateral) buds


  Located in the leaf axils and give rise to vegetative branch stems or to flowers
• Terminal buds


  Present at the tips of the main stem and branches and contain the apical meristem tissues
• Shoot originates


  In the embryo at the end opposite the root
• Apical meristem


  The growing point of the shoot, surrounded by developing leaves (leaf primordia) that have in their axils bud primordia
• Buds


  Of two kinds: Vegetative (develop into leafy branches) and Reproductive (contain rudimentary reproductive tissues and will produce flowers)
• Auxins (hormones)


  Produced in the tip, ordinarily inhibit the growth of the lateral bud primordia, and they remain dormant for some time if the apical bud exerts apical dominance over the lateral buds
• Apical dominance


  If weak, axillary buds develop into branches soon after the terminal shoot elongates, resulting in a plant with many, branched stems
• Characteristics of wind pollinated flowers

  • Flowers are small and inconspicuous but are borne in large inflorescences
  • Dull coloured small petals without fragrance
  • Flowers produce enormous numbers of light, powdery and smooth pollen grains
  • Anthers are large and are loosely attached to long filaments
  • Stigmas are large and feathery and hang outside the flower
• Characteristics of insect pollinated flowers

  • Flowers are large and conspicuous
  • Flowers are brightly-coloured. In cases where the petals are pale and inconspicious, other parts are modified into large bright petal-like structures which attract insects
  • Flowers which are pollinated by nocturnal insects (e.g, moth) are strongly-scented and secrete nectar
  • Flowers have a particular shape to facilitate pollination by particular types of insects
  • Flowers produce relatively small quantities of large sticky or spiky pollen grains
  • Stigmas are flat or lobed and have sticky surfaces