Ketosis in cows

Ketosis is the most common metabolic disorder on modern dairy farms. It arises from negative energy balance during intensive lactation after calving, and is especially common in its subclinical form.

Causes

Lack of energy

Milk synthesis needs large amounts of glucose: about 50 g of glucose for 1 litre of milk with 4.8 % lactose and 4 % fat. When dietary carbohydrates fall short, the cow draws on body fat and muscle.

Stage of lactation

Most cases occur in the first third of lactation. Negative energy balance peaks around days 7–14 after calving; some NEB in the first 4–8 weeks is inevitable.

Body condition

High-yielding cows with high body condition scores are at high risk — the fatter a cow at calving, the more weight she tends to lose. Cows rarely develop ketosis at a BCS of 3–3.5 at calving.

Feeding

Unbalanced rations lacking carbohydrates and poor-quality feed are typical causes. Starch-rich dry-period diets can shrink rumen capacity to 50–80 litres at calving, compared with the 100+ litres needed. More chopped straw, well mixed with silage or grass, is recommended in the dry period.

Genetics

Ketosis usually affects cows with high genetic potential for milk yield, whose energy needs are hardest to meet.

Symptoms

• Acetone odour, reduced feed intake, lower milk yield and changed milk.
• Licking of the skin, sudden weight loss, sluggishness, a slightly arched back.
• In advanced cases, nervous signs: circling, crossed legs, head pressing, temporary blindness, salivation.

What it costs

20–30 % of subclinical cases may progress to clinical ketosis. Subclinical ketosis harms fertility (often more than three inseminations), contributes to early culling and indirectly to mastitis and lameness.

How to detect it

Blood tests

Blood β-hydroxybutyrate (BHB) above 1.2 mmol/l is the diagnostic standard — clinical with symptoms, subclinical without. Laboratory testing is accurate but needs qualified staff, careful sampling and shipping, and stresses the animals.

Rapid tests

Milk ketone strips and handheld meters are quick and cheap, but impractical for large herds where many cows must be tested.

With Brolis HerdLine

HerdLine measures fat, protein and lactose and tracks each cow's milk spectrum at every milking. A rising fat-to-protein ratio flags cows at risk, so they can be treated before clinical signs. How HerdLine detects NEB.

Treatment

A veterinarian prescribes treatment based on severity and cause. High-fibre, well-prepared roughage stimulates the rumen; glucoplastic substances (sodium propionate, propylene glycol, glycerol, monensin) help restore energy faster.

Prevention

• Keep body condition optimal — BCS 3.0–3.5 at calving.
• Add small amounts of higher-energy concentrate a couple of weeks before calving; change diets gradually after calving.
• Watch cows closely in the first month after calving; milk fever, metritis and retained placenta raise the risk.
• Keep fresh cows in a separate group and minimise stress.
• Monitor milk with HerdLine, especially in early lactation.