Health guide

Metabolic disorders

Most metabolic disorders start in the transition period, three weeks before to three weeks after calving. They are linked: one problem often leads to the next.

Milk fever (hypocalcemia)

Parturient paresis

Around calving

What is it?

A drop in blood calcium at the start of lactation, when colostrum and milk suddenly draw large amounts of calcium. The clinical form makes the cow go down; the subclinical form has no visible signs but is far more common.

When & who is at risk

First 24–72 hours after calving. Higher risk in older cows (3rd lactation and above), Jerseys, over-conditioned cows and when the close-up ration is high in potassium.

Signs

Early: restlessness, muscle tremors, cold ears. Then: the cow lies on her chest, often with her head turned to the flank, reduced rumen movement and constipation. Late: lying on her side, bloat, coma. Subclinical: no signs, but more ketosis, displaced abomasum, retained placenta and metritis.

How to check

Blood calcium in the first 48 hours after calving. In anionic close-up programs, group urine pH (about 5.5–6.0 in Holsteins) shows whether the diet works.

Prevention through nutrition & management

Negative DCAD close-up ration (about −100 to −150 mEq/kg DM for the last ~21 days) with low-potassium forages; magnesium around 0.4% of DM; avoid over-conditioned cows. High-risk cows can receive oral calcium at calving as advised by your veterinarian.

Herd target

Clinical milk fever below 1–2% of calvings.

DCAD article →DCAD calculator →

Ketosis

Acetonaemia

Early lactation

What is it?

In early lactation the cow uses more energy for milk than she eats (negative energy balance). She mobilises body fat, and when the liver cannot process it completely, ketone bodies such as BHB build up in the blood.

When & who is at risk

Mostly 5–21 days in milk. Higher risk in fat cows at calving, cows with low intake around calving and after milk fever or other fresh cow diseases.

Signs

Reduced appetite (first concentrate, then forage), falling milk yield, weight loss, firm dry manure, sometimes a sweet acetone smell on the breath. Rarely nervous signs. Most cases are subclinical.

How to check

Blood BHB with a hand-held meter in fresh cows: 1.2 mmol/L or higher = subclinical, 3.0 or higher = clinical. Milk BHB/acetone and a fat-to-protein ratio above about 1.4–1.5 in early lactation are useful herd signals.

Prevention through nutrition & management

BCS 3.0–3.5 at calving; avoid overfeeding energy in the dry period; maximise intake around calving (enough bunk space, fresh feed, few pen moves); rumen-protected choline; monensin where permitted. Treatment (e.g. propylene glycol) according to your veterinarian.

Herd target

Subclinical ketosis in fewer than 10–15% of tested fresh cows.

Transition risk check →

Fatty liver

Hepatic lipidosis

Around calving

What is it?

When more body fat reaches the liver than it can burn or export, triglycerides accumulate in liver cells. Liver function falls, which feeds ketosis and weakens immunity.

When & who is at risk

Develops in the days around calving, especially in over-conditioned cows and cows whose intake drops sharply before calving.

Signs

Often none on its own; seen as ketosis that does not respond well to treatment, poor appetite, more fresh cow diseases and poor fertility.

How to check

Liver biopsy is the definitive test (veterinary). On farm: high BHB and NEFA around calving and high BCS losses point to the problem.

Prevention through nutrition & management

Control BCS in late lactation and the dry period; avoid feed restriction and stress before calving; rumen-protected choline helps the liver export fat.

Herd target

Cows lose no more than about 0.5–0.75 BCS points after calving.

Scoring guides →

Subacute ruminal acidosis (SARA)

Rumen acidosis

Early lactation · high-starch diets

What is it?

Rumen pH stays below about 5.6 for more than 3 hours a day. Fibre digestion falls, the rumen wall is damaged and bacterial toxins can enter the blood.

When & who is at risk

Early lactation and whenever rations are high in rapidly fermentable starch and low in effective fibre; also with sorting and slug feeding.

Signs

Day-to-day swings in intake, less rumination, loose foamy manure with undigested fibre, falling milk fat; weeks later laminitis and liver abscesses.

How to check

Rumination data, manure scoring, milk fat/protein, Penn State separator checks of fresh TMR and refusals; rumenocentesis or pH boluses for confirmation.

Prevention through nutrition & management

Enough physically effective fibre, starch level matched to its fermentability, buffers, consistent mixing, feed always available, no overcrowding and gradual ration changes.

Herd target

Milk fat and rumination stable; fewer than 25% of tested cows with rumen pH ≤5.5.

Rumen acidosis article →Penn State separator →

Acute rumen acidosis (grain overload)

Lactic acidosis

Emergency

What is it?

A sudden intake of a large amount of grain or other rapidly fermentable feed. Lactic acid builds up, rumen pH falls below 5, and acid and toxins spread through the body.

When & who is at risk

Access to a grain store, feeding mistakes, sudden switch to a high-grain diet (especially in feedlot cattle and sheep).

Signs

Within hours: no appetite, bloat, diarrhoea with a sour smell, dehydration, staggering, lying down; can be fatal.

How to check

Clinical diagnosis by a veterinarian (rumen fluid pH, history). Call your veterinarian immediately.

Prevention through nutrition & management

Secure grain storage; adapt animals step by step to high-concentrate diets over 2–3 weeks; accurate weighing and mixing; ionophores where permitted in beef rations.

Herd target

No cases: every case is a management error.

Beef cattle nutrition →

Displaced abomasum

LDA / RDA

First month after calving

What is it?

The abomasum fills with gas and moves out of place, most often to the left side. Feed flow slows and the cow eats and milks less.

When & who is at risk

Mostly in the first 4 weeks after calving; risk rises with low intake before calving, hypocalcemia, ketosis, metritis and a small rumen fill.

Signs

Reduced appetite (especially for concentrate), less milk, less manure, a ‘ping’ sound on the left side when the vet taps and listens.

How to check

Diagnosis by a veterinarian (percussion and auscultation). Track DA rate per calving as a transition indicator.

Prevention through nutrition & management

Maximise intake before and after calving, keep rumen fill high with good-quality forage and enough effective fibre, prevent hypocalcemia and ketosis.

Herd target

DA in fewer than 2–3% of calvings.

Rumen fill score →

Grass tetany (hypomagnesaemia)

Low blood magnesium

Lush spring pasture

What is it?

Low blood magnesium. Magnesium is absorbed mainly from the rumen, and high potassium and nitrogen in lush grass reduce this absorption.

When & who is at risk

Grazing lush, fast-growing grass in spring or autumn, cold wet weather, older cows in early lactation, beef cows nursing calves.

Signs

Nervousness, muscle twitching, staggering, convulsions; animals can be found dead.

How to check

Blood or urine magnesium in the risk group; this is an emergency, call your veterinarian.

Prevention through nutrition & management

Supplement magnesium (e.g. magnesium oxide in the ration or mineral mix) during risk periods; offer hay or straw with pasture; avoid heavy potassium fertilisation of grazing land.

Herd target

No cases in the risk season.

Bloat

Ruminal tympany

Legume pasture · feedlot

What is it?

Gas is trapped in the rumen. In frothy bloat the gas is caught in a stable foam (lush legumes, finely ground grain); in free-gas bloat the cow cannot belch it out (for example because of a blockage in the oesophagus).

When & who is at risk

Grazing wet, lush alfalfa or clover; high-grain feedlot diets with little roughage.

Signs

Swollen left flank, discomfort, laboured breathing, animals may die quickly.

How to check

Emergency: call your veterinarian. Watch high-risk groups closely in the first hours on pasture.

Prevention through nutrition & management

Fill animals with hay before turning out to legume pasture; avoid wet legumes; grass–legume mixtures; enough coarse roughage and not too finely ground grain in feedlot diets; anti-bloat products where appropriate.

Herd target

No cases.

Milk fat depression

Low milk fat

Any stage

What is it?

Milk fat falls without a similar drop in milk yield. It is mainly caused by specific fatty acids formed in the rumen when fermentation shifts (for example trans-10, cis-12 CLA), not only by low fibre.

When & who is at risk

High-starch rations, low effective fibre, high levels of unsaturated oils (e.g. distillers grains, oilseeds), sorting, ionophores combined with risky diets.

Signs

Bulk tank fat below the herd’s normal level; more cows with a fat-to-protein ratio below 1.0–1.1.

How to check

Test-day fat and fat/protein by group; de novo fatty acids in milk if available; review ration fat sources and fibre.

Prevention through nutrition & management

Limit unsaturated fat from oils and by-products, keep enough effective fibre, match starch to fermentability, feed consistently; rumen-inert saturated fats can support milk fat.

Herd target

Stable milk fat at the herd’s breed-typical level.

This guide is educational and focuses on prevention through nutrition and management. Diagnosis and treatment of sick animals are the job of your veterinarian.

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