Ration balancing for a crossbred cow on a smallholder farm
Ramesh keeps three crossbred cows in a village near Etawah. His best cow, in third lactation and 45 days calved, weighs about 450 kg and gives 12 litres a day. She receives 5 kg wheat straw, about 8 kg limited green berseem and 2 kg of a home-made concentrate (50% maize, 30% mustard cake, 20% wheat bran) in two feeds. No mineral mixture or salt is given. Body condition has fallen from 3.0 to 2.25, milk fat is 3.1%, and she is not reaching the 15 litres she gave in the previous lactation. The farmer proposes to add another 1.5 kg mustard cake to raise milk. Wheat straw is cheap but berseem will run out in three weeks; maize and mustard cake prices have risen. There is no chaff cutter and the cows are watered twice daily.
1. What are the most likely nutritional constraints in this ration, and why is adding 1.5 kg mustard cake a poor first response? Give your reasoning.
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The first constraint is energy, not protein alone. A 450 kg cow giving 12 litres needs roughly 6.0–6.5 kg TDN and 0.9–1.0 kg DCP per day including maintenance. The present ration supplies only about 4.5–4.8 kg TDN: 5 kg wheat straw is bulky and low in digestible energy, 8 kg berseem is useful but limited, and 2 kg concentrate cannot fill the gap. The falling body condition and failure to reach the previous peak support an energy deficit.
Mustard cake is a useful protein source, but 1.5 kg extra would take total mustard cake to about 2.1 kg/day. Mustard cake contains glucosinolates and is unpalatable in excess; it can depress feed intake, cause digestive disturbance and taint milk. It would also widen the mineral imbalance, because no mineral mixture or salt is given and cereal straw diets are already poor in calcium, phosphorus and trace elements. The extra protein would be used as expensive energy rather than correcting the primary deficit.
A better response is to raise energy density with maize or barley, keep mustard cake within about 0.5–0.8 kg, add wheat bran for bulk, and provide 50–100 g mineral mixture and 30–50 g salt. Chaffing straw would improve intake and reduce wastage. The farmer should judge the change by body condition, intake, milk yield and cost per litre over 2–3 weeks, not by a single day's yield.
2. Propose a revised daily ration using locally available feeds, stating quantities and the reasoning behind each change.
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A practical starting point for the 450 kg cow giving 12 litres is:
- Wheat straw: 4–5 kg, chaffed, fed after green fodder to limit selective refusal.
- Green berseem or other green fodder: 10–12 kg while available; when berseem ends, replace part with maize fodder or limited vegetable waste, not more straw alone.
- Concentrate: about 4 kg/day, split into two or three feeds. A workable mix is maize 2.0 kg, wheat bran 1.0 kg, mustard cake 0.7 kg, and mineral mixture 50–70 g plus salt 40 g. If maize is expensive, use barley or broken rice in part.
- Water: free access at least three times daily, especially after concentrate feeding.
The concentrate increase supplies the missing energy; the moderate mustard cake level supplies protein without excessive glucosinolates; wheat bran adds bulk and phosphorus; mineral mixture corrects calcium, phosphorus and trace-element gaps. The ration should be introduced gradually over 7–10 days to avoid rumen upset. Recalculate after three weeks: if milk reaches 14–15 litres and body condition stabilises, maintain it; if the cow gains condition too fast, reduce maize slightly. Cost per litre should be checked against the local milk price before scaling the ration to the other cows.
3. What records and management checks should the farmer use to decide whether the new ration is working economically?
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The farmer should record daily milk yield, feed offered and refused, and weekly body condition score for at least three weeks. Milk fat and protein should be tested if the buyer pays on quality. Feed cost per litre should be calculated as total daily feed cost divided by daily milk yield; a ration that raises yield but costs more per litre than the milk price destroys margin.
The farmer should also watch rumen fill, dung consistency, lameness and heat signs. A gradual rise in yield with stable dung and no off-feed is a good sign. If intake falls or milk taints appear, reduce mustard cake first. Body condition should move towards 2.75–3.0 over two months, not rapidly. Finally, compare the cost of the revised concentrate with the value of the extra milk and consider whether chaffing and mineral mixture are affordable. The decision should be based on marginal return, not on yield alone.