Feeding and Nutrition of Livestock
Feed classification
The exam tests roughage/concentrate balance, nutrient terms such as TDN and DCP, conservation methods and ration formulation. You should be able to calculate a simple concentrate allowance and spot an imbalanced ration.
Core rules and concepts
- Roughages include green fodder, dry fodder and silage; concentrates supply energy and protein in a small volume.
- TDN measures energy; DCP measures digestible crude protein. A balanced ration meets maintenance plus production needs.
- Dry-matter intake is roughly 2.5–3% of body weight; a common thumb rule is 1 kg concentrate per 2.5 L milk plus 1.5–2 kg for maintenance.
- Urea treatment raises the digestibility of straw, but urea must never be fed to young calves and must be introduced gradually.
- Silage is made from green fodder at proper moisture; hay is dried fodder. Mineral mixture and clean water are essential.
Worked example
A cow yielding 10 L/day needs maintenance concentrate of 2 kg plus production concentrate of 10÷2.5=4 kg, giving 6 kg concentrate. If the cow also gets 25 kg green fodder, the concentrate is not a substitute for roughage. The reasoning uses the yield rule and keeps roughage in the ration.
Traps that cost marks
Do not feed more concentrate as a shortcut to more milk; it can cause acidosis. Do not feed urea to calves. Do not ignore mineral mixture. Do not confuse TDN with DCP. Do not formulate a ration on cost alone without checking nutrient balance.