Concentrate overload in a freshly calved crossbred cow
Ramesh keeps six crossbred cows (Holstein-Friesian × Jersey) near Khurda and pours milk at his village Dairy Cooperative Society. Until last month each cow got paddy straw free choice plus 1 kg of a rice-bran and groundnut-cake mix at each milking, and averaged 9 litres a day. After a training session he decided to push for more milk. He raised the concentrate to 4 kg per cow per day in two feeds and bought 60 kg of cheap, damaged maize from a trader, adding 2 kg of it per cow daily. Three days later, cow No. 4 - second lactation, calved 15 days ago, milking 12 litres - refused concentrate and then refused fodder. Her left flank is distended, her dung is loose, sour-smelling and shows visible grain particles, she chews her cud only occasionally, and her rectal temperature is 39.2 °C. Two herd-mates are cudding less than usual but are still eating. Ramesh has no fodder analyser, no rumen pH meter, and a veterinary assistant 20 km away.
1. What is the most likely diagnosis, and why did the freshly calved cow go down first while the others only slowed down?
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Diagnosis: subacute to acute rumen acidosis (grain overload).
The reasoning chain:
- Concentrate is not the problem in itself; the rate of change is. Rumen papillae and the fibre-digesting microbes need 2–3 weeks to adapt to a higher starch load.
- The fresh calver is the highest-risk animal. She is 15 days calved, still in negative energy balance, and had not stabilised her intake - yet she received the same 4 kg plus 2 kg of finely broken maize as cows giving 9 litres. Her concentrate-to-milk ratio was far above the normal ceiling of about 1 kg per 2.5 litres.
- Loose, sour dung containing whole grain means starch is escaping rumen fermentation and being fermented lower down; cud chewing has fallen, so less saliva (the cow's natural bicarbonate) is swallowed. Rumen pH is almost certainly below 5.8.
- A temperature of 39.2 °C is normal-to-slightly-high for a cow. It argues against an infectious cause and fits a rumen disturbance.
- The herd pattern - two others cudding less but still eating - is the classic dose-related spread of a feeding error, not a contagious disease.
Damaged maize also carries a mould risk, but the timing and the group pattern point to fermentable carbohydrate load first.
2. Give a day-by-day corrective plan for the next 14 days, with quantities.
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Day 1: Withdraw all concentrate and maize immediately. Offer good green fodder or legume hay free choice and clean water. Drench 100 g sodium bicarbonate in 10 litres of lukewarm water, and give 10 g of live yeast. Call the veterinary assistant if she is not eating within 12–24 hours, if she becomes recumbent, or if her temperature rises. In a severe case the vet may need to pass a stomach tube and transfuse rumen fluid from a healthy cow.
Days 2–4: Same supportive care. Start 250 g of concentrate split into three small feeds.
Days 5–14: Increase concentrate by 250 g every second day, up to a ceiling of 1 kg per 2.5 litres of milk, never more than 2 kg in a single feed and never more than 4 feeds a day. Add 50–100 g mineral mixture and 30–50 g common salt daily. Always put 25–30 kg of green fodder in front of her before the concentrate.
Group rule: Feed by production group, not one mix for all. Fresh calvers need their own slowly rising ration for the first three weeks. Note in the farm diary that 4 kg was reached in three days - the mistake was speed, not the amount.
3. Which routine records or observations would have flagged the risk before she went off feed, and what should go into the written feeding calendar?
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Early warning indicators:
- Cud chewing: a healthy cow gives 55–65 chews per bolus and chews 6–8 hours a day. A drop is the earliest visible sign.
- Dung consistency score checked daily; loose, sour dung with grain particles is a red flag.
- Feed refusals - even 0.5 kg left in the manger.
- Weekly individual milk weights; a fall in one cow before any disease sign.
- Milk fat:protein ratio from the society's fat and SNF slip; fat falling below protein is a classic acidosis signal.
What the feeding calendar must state: maximum concentrate per single feed (2 kg), ceiling per litre of milk (1 kg per 2.5 L), the transition rule (250 g every second day), who checks dung and cud every morning, and the name of the person who signs the feed register. Records must be written in the farm diary at the time, not recalled later - otherwise the same error repeats at the next calving.