A thin dairy herd with poor water, no minerals and long calving intervals
Mrs Phiri keeps eight crossbred cows (Friesian × Malawi Zebu, about 50% exotic) near Mzuzu. The herd averages 6 litres per cow per day, although the same cows gave 11–12 litres in their first lactation. Body condition scores are mostly 2.0 on a 1–5 scale, and the calving interval has risen to 19 months. The last three cows were first served 130–150 days after calving and conceived only at the third or fourth service. Cows graze natural pasture for about six hours a day and receive 2 kg of maize bran each evening; no minerals or legume forage are given. Water is carried from a stream 1 km away and the trough is often empty by midday. Two cows have had retained placentas and one is lame with swelling at the coronary band. She has MK 180,000 per month to spend and can borrow up to MK 500,000 at 25% annual interest from a village savings group.
1. Rank the herd's constraints in order of importance and explain how each one links to the milk yield and the 19-month calving interval.
Read the worked answer
1. Water. A milking cow needs 40–60 litres a day and milk is about 87% water. A trough empty by midday in a six-hour grazing system caps feed intake as well as water intake, so the 2 kg of bran cannot express its value.
2. Energy and protein. Two kilograms of maize bran supplies roughly 1.6 kg dry matter, about 7 MJ metabolisable energy and 8–9% crude protein. A 450 kg cow giving 10 litres needs roughly 90–110 MJ ME and 1.4–1.7 kg CP a day. The gap is large and explains the fall from 12 to 6 litres.
3. Body condition and reproduction. A score of 2.0 shows a prolonged negative energy balance. Thin cows resume cycling late, show weak or silent heats and conceive after several services - exactly the 130–150 day first service and 3–4 services per conception reported. The calving interval is a symptom, not the primary fault.
4. Minerals. A grass-only diet with no supplement is short of calcium, phosphorus, selenium and trace elements; retained placenta is associated with selenium, iodine and energy deficits. A mineral supplement is justified but will not substitute for energy.
5. Lameness at the coronary band needs examination - it reduces grazing time and intake, and may be an infectious or traumatic cause that spreads.
2. Design a three-month plan that fits MK 180,000 per month and say what you would do first.
Read the worked answer
Spend where the physical response is largest per kwacha, not where the symptom is most visible.
Month 1 - water first (one-off about MK 120,000 plus monthly labour)
- One 1,000-litre tank or two 200-litre drums and a trough at the kraal, filled twice daily by a paid helper at MK 25,000/month. This is the cheapest gain available and needs no borrowing.
Month 1–3 - feed (about MK 55,000/month)
- Raise maize bran from 2 to 3 kg and add 0.5 kg cottonseed cake or 1 kg legume hay per cow per day. For eight cows the extra 8 kg/day is about five 50 kg bags a month.
- One mineral block or loose mineral mix, roughly MK 15,000/month.
- Sow 0.2 ha of lablab or velvet bean now (seed about MK 20,000) for dry-season forage.
Reproduction (about MK 5,000/month)
- Tail chalk or paint and structured observation for 30 minutes twice daily, with a simple record card per cow.
- Have the lame cow and the two with retained placentas examined; treat the foot, do not simply cull.
Total recurring cost is about MK 100,000/month, leaving a buffer for treatment and transport; the one-off water investment is met from savings rather than the 25% loan.
3. What would you measure at 30, 60 and 90 days to judge whether the plan is working, and what would make you change course?
Read the worked answer
Judge the plan on leading indicators, not on calving interval, which cannot change within three months.
30 days: water in the trough at mid-afternoon (should never be empty), daily milk record per cow (target +1 litre), and whether every cow has been seen standing to be mounted at least once.
60 days: milk up by 2 litres on the herd average; body condition moving from 2.0 towards 2.5; heats detected in at least half the cows that are more than 60 days calved; lame cow sound.
90 days: body condition 2.5–3.0, submission rate (cows served within 85 days of calving) above 50%, and conception confirmed at pregnancy diagnosis. Record services per conception for the next calving interval.
Change course if:
- Milk has not moved after water and an extra kilogram of concentrate - re-examine for mastitis, ticks, internal parasites or chronic disease before buying more feed.
- Heats are still not being seen while body condition is improving - the fault is detection or a genuine reproductive problem, so ask for a veterinary fertility examination rather than more feed.
- Body condition is improving but milk is not - check the protein source and whether the bran is diluting rather than supplementing the ration.
Do not judge success by the calving interval at 90 days; only the intermediate measures can still be acted on.