Butterfat slump on a Murrah buffalo unit
A Murrah buffalo unit in Kolhapur milks eight animals averaging 9 L/day. For ten days the bulk milk fat has fallen from 6.4% to 5.2%, while the owner has raised cottonseed cake from 3 kg to 6 kg per head daily to improve energy. The visible ration is wheat straw ad libitum, about 22 kg green maize, 2 kg rice bran and no mineral mixture. Two buffaloes have a body condition score of 2.75/5 and one shows depraved appetite. Water is available twice daily. Milk price is ₹38/L and the owner wants feed cost below ₹10/L. The local feed market has maize grain, wheat bran, soybean meal, cottonseed cake, mineral mixture and common salt, but no bypass fat. The veterinarian has ruled out mastitis and metritis. The owner asks whether to increase cottonseed cake further or change the ration.
1. What is the most likely nutritional explanation for the butterfat decline, and which two facts in the setup argue against simply adding more cottonseed cake?
Read the worked answer
The pattern points to rumen fermentation being pushed toward low acetate and high propionate, with a likely subacute acidosis and oil effect rather than a shortage of protein. Cottonseed cake is not a fibre source; at 6 kg it supplies a large amount of oil and gossypol, and the ration already has rice bran, another oil-rich feed. Raising it further would increase unsaturated fat in the rumen, depress fibre digestion and can lower butterfat further. The two contrary facts are: (a) the decline began while cottonseed cake was being increased, so the change is temporally associated with the problem; (b) the ration has no mineral mixture and one buffalo shows depraved appetite, suggesting a mineral imbalance or poor effective fibre, not a simple energy deficit. The low body condition in two animals also shows that total nutrient supply is inadequate, so the answer is to rebalance the ration, not add one concentrate.
2. Draft a practical daily ration for one 450 kg buffalo producing 9 L at 6.5% fat using feeds on hand, and state the feeding sequence.
Read the worked answer
A workable starting ration per head per day is: wheat straw 4 kg; green maize 20 kg; maize grain 1.5 kg; wheat bran 1.0 kg; soybean meal 0.7 kg; cottonseed cake 2.0 kg; rice bran 1.0 kg; mineral mixture 60 g; common salt 40 g; sodium bicarbonate 50 g. This reduces the oil load from cottonseed cake and rice bran, adds a safer protein source, and supplies minerals. Mix the concentrates and minerals and offer half before milking and half in the afternoon; give green maize after milking and wheat straw in the trough so that effective fibre is available through the day. Introduce the change over 5 to 7 days. Check the cost: roughly 1.5 kg maize, 1 kg bran, 0.7 kg soybean meal and 2 kg cake should keep feed cost near ₹90 to ₹110 per animal, which is about ₹10 to ₹12 per litre at 9 L. If cost exceeds the target, replace some maize grain with wheat bran rather than increasing cottonseed cake.
3. How would you monitor the response over 21 days and what would make you revise the ration?
Read the worked answer
Record daily milk yield and bulk fat, and test each buffalo separately at day 0, 7, 14 and 21 so that dilution by low-fat animals is not hidden. Score body condition and rumen fill weekly, observe cud chewing and faecal consistency, and note refusal of wheat straw. A rise of 0.4 to 0.6 percentage points in fat within two weeks, stable yield and better appetite would justify continuing. Revise if fat remains below 5.8% at day 21, if yield falls by more than 0.5 L/animal, if faeces become loose or acidic, or if feed cost exceeds ₹12/L. In that case, increase effective fibre, reduce rice bran first, and check for gossypol effects such as dullness or poor fertility. Also test the water supply and mineral premix quality, because twice-daily watering can limit intake in hot weather.