Theory question 107
Pasture and Forage Crops(a) State four ways in which rangeland is important in livestock production.
(b) If the recommended grazing area per cattle is 3m x 3m. Calculate in hectares the carrying capacity of the rangeland illustrated in the diagram below.
(c) State two benefits of each of the following management practices in animal production: (i) dipping; (ii) vaccination; (iii) artificial insemination.
Show the model answer
(a) Any four: cheap source of feed (grass and legumes); grazing space for large herds; provides water and shade; serves as source of hay and silage; reduces cost of production; allows exercise and natural mating.
(b) The field is a rectangle 250 m × 114 m with a semicircle (radius 57 m) at each end.
Rectangle = 250 × 114 = 28,500 m²; two semicircles = πr² = 3.142 × 57 × 57 ≈ 10,208 m².
Total ≈ 38,708 m² ≈ 3.87 ha.
Area per animal = 3 m × 3 m = 9 m² = 0.0009 ha.
Carrying capacity = 3.87 ha ÷ 0.0009 ha ≈ 4,300 cattle on 3.87 ha.
(c)(i) Dipping: kills external parasites (ticks, lice); prevents tick-borne diseases.
(ii) Vaccination: protects animals from specific diseases; prevents disease outbreaks and losses.
(iii) Artificial insemination: one good male serves many females; spreads improved genes; prevents spread of sexually transmitted diseases; no need to keep a bull.
In (b) remember the two half-circles at the ends.