Balancing a Crossbred Cow's Ration on a Smallholding
A farmer in Muzaffarpur keeps one crossbred cow (HF × Sahiwal), 450 kg body weight, in her second lactation, giving 12 kg milk daily in the fourth month. The current ration is wheat straw ad libitum, 3 kg rice bran and 1 kg mustard cake per day, with no mineral mixture. The cow is losing body condition (body condition score 2.0 on a 5-point scale), milk yield has fallen from 14 to 12 kg/day in three weeks, and the milk fat is 3.5%. The farmer has wheat straw, berseem green fodder, maize grain, mustard cake, rice bran, wheat bran, common salt and a mineral mixture. He can spend about ₹80/day on concentrate and wants to know whether adding more rice bran or more mustard cake is the cheapest way to raise milk. The local milk cooperative pays ₹32/kg milk and deducts ₹2/kg for collection.
1. Estimate the cow's total dry-matter intake and the roughage-to-concentrate ratio. Is the current ration adequate?
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A 450 kg crossbred cow eats roughly 2.5–3.0% of body weight as dry matter, i.e. about 11–13.5 kg DM/day; use 12.5 kg DM as a working figure. For 12 kg milk she needs roughly 1.4–1.5 kg crude protein and 8–9 kg TDN. The current ration is low in protein: 3 kg rice bran supplies only about 0.25–0.3 kg CP and 1 kg mustard cake about 0.35 kg CP, so the concentrate provides about 0.6 kg CP; wheat straw adds little protein. The cow is therefore mobilising body reserves, which explains the falling milk and BCS 2.0. The roughage:concentrate ratio is roughly 65:35 on DM, but the roughage is almost all low-quality straw. The fix is not simply more rice bran-it is energy-rich but low in protein and high in fat-but a better-balanced concentrate plus good green fodder.
2. Formulate a cost-effective daily concentrate mix using the available feeds, and calculate how much to feed.
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Use berseem to cut concentrate cost. Offer 8–10 kg green berseem and 5–6 kg wheat straw, plus about 4–4.5 kg of a concentrate mix. A practical mix for 4 kg is: maize 1.5 kg, wheat bran 1.0 kg, mustard cake 1.2 kg, rice bran 0.3 kg, mineral mixture 50 g and salt 30 g. This gives roughly 0.7 kg CP from the concentrate, about 17–18% CP, and the berseem adds further protein. Mustard cake should not exceed about 1.5 kg/day because of glucosinolates. If ₹80/day is a hard limit, reduce maize and use more wheat bran, but do not replace mustard cake with more rice bran; rice bran is cheap per kg but poor in quality protein. Feed the concentrate in two or three equal parts after milking, and introduce the new mix over 7 days.
3. What would you tell him about mineral mixture, salt and feeding frequency, and how would you monitor the response?
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Provide mineral mixture at 50 g/day and common salt at 30 g/day; these are cheap and correct the likely calcium, phosphorus and trace-mineral gaps. Ensure clean water at all times. Divide the concentrate into 2–3 feeds rather than one large feed, and offer roughage first to maintain rumen function. Monitor milk yield, body condition score and milk fat weekly for 3–4 weeks; a rise in milk and BCS indicates the ration is working. If milk does not improve, check for mastitis, heat stress, internal parasites and water quality, and get the fodder analysed. Do not change the ration abruptly; rumen microbes need adaptation.