A Milk Yield Drop in a Ten-Buffalo Dairy
A farmer keeps 10 Murrah buffaloes, six of them in milk, averaging 7.2 L/day at 6.8% fat. Over 10 days two buffaloes fall from about 7.0 L to 4.0 and 3.5 L/day. The ration is unchanged: berseem ad libitum, 4 kg wheat straw, and 1 kg concentrate (18% CP, 70% TDN) for every 2.5 L of milk, plus 1 kg for maintenance. Both affected animals show flakes in foremilk; one has a hot, swollen left hind quarter. The cooperative's bulk sample tests 850,000 somatic cells/mL and chloride 0.18%. The local veterinarian has left 100 mL of oxytetracycline injection and advises treating all six buffaloes 'to be safe'. Milk price is Rs 38/L; a 500 mg intramuscular dose costs Rs 120; the cooperative rejects milk with antibiotic residues and pays a Rs 2/L quality premium.
1. Diagnose the likely cause of the drop and decide whether all six buffaloes should be treated. Give the evidence and the immediate actions.
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Diagnosis
Only two of six milking animals are affected, and the ration has not changed. The combination of a sudden drop in two animals, flakes in foremilk, a hot swollen quarter, bulk SCC of 850,000 cells/mL and chloride of 0.18% points to mastitis, not a herd-level feed problem. Chloride above about 0.14% supports increased permeability of the udder. A feed cause would usually affect more animals and would not produce unilateral heat and swelling.
Decision on treatment
Treating all six is not justified. It exposes four apparently healthy buffaloes to antibiotics, increases residue risk, and costs money without evidence. The correct immediate actions are:
- Examine each buffalo with a California Mastitis Test and strip each quarter onto a strip cup.
- Collect an aseptic milk sample from the affected quarters before any antibiotic, and request culture and sensitivity.
- Start treatment only for the clinical case, following the veterinarian's prescription and label withdrawal period. Oxytetracycline is not a substitute for sensitivity testing.
- Milk affected animals last, use separate udder cloths, and post-milking teat-dip.
- Check the milking machine vacuum and liners; poor machine function can spread infection.
Economic point
A blanket course for six animals costs six times the drug cost and may cause the cooperative to reject the whole bulk tank. The farmer's quality premium of Rs 2/L is worth more than the apparent saving from 'insurance' treatment.
2. The farmer wants to stop feeding concentrate to the two affected buffaloes until they recover. Evaluate this proposal and calculate the approximate daily concentrate saving or loss.
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Evaluation
Stopping concentrate in early lactation is a false economy. Mastitis increases maintenance demand and reduces feed intake, so the affected buffaloes are already at risk of negative energy balance. Withholding concentrate will lower milk further, delay recovery, and reduce fertility.
Concentrate calculation
Using the farmer's rule of 1 kg concentrate per 2.5 L plus 1 kg maintenance:
- A 4.0 L buffalo needs 4.0/2.5 + 1 = 2.6 kg/day.
- A 3.5 L buffalo needs 3.5/2.5 + 1 = 2.4 kg/day.
If concentrate costs about Rs 30/kg, stopping it saves roughly Rs 78 and Rs 72/day, or about Rs 150/day for the two animals. But the milk lost at Rs 38/L is much larger: even 2 L/day per animal is Rs 152/day for the two, before accounting for body-condition loss and delayed conception. If the milk is discarded because of antibiotic residues, the feed saving is still not a reason to withdraw concentrate; the animal needs nutrients to mount an immune response and return to production.
Recommendation
Keep the concentrate at the calculated level, split into two feeds, and ensure clean water. Do not change the whole ration abruptly. Reassess after the withdrawal period and after milk yield stabilises.
3. Design a 30-day plan to bring the bulk tank SCC down and protect the quality premium. Include records and a culling decision.
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30-day plan
Days 1–3: identify and separate
- Test every quarter of every milking buffalo with CMT and record results.
- Collect individual milk samples for SCC or culture from high-CMT animals.
- Milk clinical and high-SCC animals last; use separate cloths and disinfect clusters between animals.
Days 4–14: treat and correct hygiene
- Treat only confirmed clinical cases under veterinary direction; observe withdrawal periods strictly.
- Check machine vacuum, pulsation rate and liner condition; replace cracked liners.
- Use pre-dip, dry wipe, full-hand milking and post-milking teat dip. Keep bedding dry and replace wet bedding.
- Record daily milk yield, CMT weekly and bulk SCC at each pickup.
Days 15–30: review and decide
- Re-test treated animals after withdrawal. If the quarter remains blind or the animal has repeated high SCC across lactations with low yield, cull. Do not cull both animals immediately on one high SCC result.
- Compare the value of keeping an animal with its replacement cost and the quality premium at stake. The premium is Rs 2/L on about 43 L/day = Rs 86/day; a chronic high-SCC cow can cost more than that through rejected milk and treatment.
- Continue monthly bulk SCC monitoring for at least three months after the tank falls below the cooperative threshold.
Record-keeping
Keep a simple herd register with date, quarter, CMT score, treatment, withdrawal end date and yield. That record is the basis for both the culling decision and proof of residue compliance.