(a) State four ways in which rangeland is important in livestock production. [4 marks] (b) If the recommended grazing area per cattle is 3m x 3m. Calculate ...

Answer Details

(a) Four ways in which rangeland is important in livestock production

1. Source of cheap natural feed: rangeland supplies natural pasture (grasses and legumes) which grazing animals feed on directly, greatly reducing the cost of buying feed.
2. Supply of water: streams, ponds and other natural water sources found within the rangeland provide drinking water for the livestock.
3. Space for exercise and free movement: the open land gives the animals room to move about and exercise, which keeps them healthy and reduces stress.
4. Shelter and shade: the scattered trees and shrubs on the rangeland provide shade and protection against harsh weather (sun, wind and rain).

(Also acceptable: habitat and breeding ground for natural mating; source of mineral licks and medicinal plants.)

(b) Carrying capacity of the rangeland

From the diagram, the rangeland is a stadium shape: a central rectangle with a semicircular end on each side.

• Length of the straight (rectangular) portion \(= 250\,\text{m}\)
• Width \(= 114\,\text{m}\), so each semicircle has diameter \(114\,\text{m}\) and radius \(r = \dfrac{114}{2} = 57\,\text{m}\)

Step 1: Area of the rectangular portion

\[A_{\text{rect}} = L \times W = 250 \times 114 = 28{,}500\,\text{m}^2\]

Step 2: Area of the two semicircular ends

The two equal semicircles together make one full circle of radius \(57\,\text{m}\). Taking \(\pi = \dfrac{22}{7}\):

\[A_{\text{circle}} = \pi r^2 = \frac{22}{7} \times 57^2 = \frac{22}{7} \times 3249 = 10{,}211.14\,\text{m}^2\]

Step 3: Total area of the rangeland

\[A_{\text{total}} = 28{,}500 + 10{,}211.14 = 38{,}711.14\,\text{m}^2\]

Step 4: Convert to hectares \((1\ \text{hectare} = 10{,}000\,\text{m}^2)\)

\[A_{\text{total}} = \frac{38{,}711.14}{10{,}000} = 3.87\,\text{hectares}\]

Step 5: Carrying capacity

Recommended grazing area per cattle \(= 3\,\text{m} \times 3\,\text{m} = 9\,\text{m}^2\).

\[\text{Carrying capacity} = \frac{\text{Total area}}{\text{Area per cattle}} = \frac{38{,}711.14}{9} = 4301.2\]

Since a fraction of an animal is not counted, the rangeland (about 3.87 hectares) can carry 4301 cattle.

(If the shape is read as a rectangle with only one semicircular end, the area \(= 28{,}500 + \tfrac{1}{2}(10{,}211.14) = 33{,}605.57\,\text{m}^2 = 3.36\ \text{ha}\), giving a carrying capacity of \(3733\) cattle.)

(c) Two benefits of each management practice

(i) Dipping

• Controls external parasites such as ticks, lice and mites on the skin and coat of the animal.
• Prevents parasite-borne diseases (for example anaplasmosis, babesiosis and heartwater) and keeps the hide healthy.

(ii) Vaccination

• Confers immunity, protecting the animal against specific infectious diseases such as anthrax, blackleg and rinderpest.
• Reduces the death rate and checks the outbreak and spread of epidemic diseases within the herd.

(iii) Artificial insemination

• Allows the use of semen from superior, proven sires so that the genetic quality and productivity of the offspring are improved.
• Prevents the transmission of breeding (venereal) diseases spread during natural mating, and lets one superior bull serve many cows even over long distances.