Animal Nutrition, Feeds and Feeding Practices
Feed classification
- Roughages (over 18% crude fibre): green - berseem, lucerne, oat, maize, jowar, bajra; dry - hay, straw, kadbi.
- Concentrates: energy - maize, barley, wheat bran, rice bran, molasses; protein - mustard cake, groundnut cake, soybean meal, linseed cake, cottonseed cake (gossypol risk).
- Additives: mineral mixture, common salt, vitamins, bypass protein, buffers.
Rules worth memorising
- Balance the ration for DCP (protein) and TDN (energy) plus minerals and water; cheap but unbalanced feed is not a balanced ration.
- Colostrum within 30–60 minutes of birth; antibodies and vitamin A are absorbed only in the first hours.
- Urea treatment of straw: 4 kg urea per 100 kg straw, moistened and sealed about 3 weeks. Never feed urea to pigs or poultry.
- Green fodder alone is bulky and energy-poor; extra concentrate is needed for production.
- Allow roughly 3–5 litres of clean water per litre of milk.
Worked example (Pearson square)
Target 18% CP from maize (9%) and mustard cake (32%).
- Maize parts = 32 − 18 = 14; cake parts = 18 − 9 = 9; total 23.
- Maize = 14/23 = 60.9%; cake = 9/23 = 39.1%.
- Check: 0.609 × 9 + 0.391 × 32 = 5.5 + 12.5 ≈ 18%. Always back-calculate.
Traps
DCP is protein and TDN is energy - never swap them; the Pearson square uses only two feeds, so fix one component before starting; urea is toxic to monogastrics; colostrum given after a day is largely wasted.