Metabolic disorders in early postpartum cows are fostered by management practices that are aimed at greater production, related to dry cow (transition cow) management and related to early postpartum period.  Metabolic disorders can invariably be prevented by ensuring the best possible dietary balance and particularly careful management of cows at drying off, during the dry period and in early lactation.

Disorder	Deaths	Culls	Lost milk (kg)	Avg. cost per case
Displaced abomasum	2.0%	8.0%	399 – 577	£202
Milk fever	4.0%	5.0%	130	£117
Ketosis	0.5%	5.0%	230	£98

Acidosis

Incorrect diets or feeding can lead to overly-rapid fermentation in the rumen, reducing the pH below the level at which the microbes are most active.  This slows down forage digestion and reduces both feed intake and cud chewing which makes the problem worse by limiting the buffering effect of salivation.  Low milk fat percentages are a common symptom of acidosis which, in severe cases, causes cows to go off their feed completely and milk yields to plummet. Cows may suffer reduced ruminal efficiency, liver and lung abscesses, and laminitis.

Acidosis can be effectively prevented by good diet formulation and feeding practice.

To prevent acidosis:

• Spread concentrate feeds over the day, use TMR or out-of-parlour feeders rather than feeding all concentrates through the parlour.
• Provide starchy feeds little and often.
• Limit parlour concentrate feeds to 4 – 4.5 kg/milking.
• Ensure separately-fed forage is of a good quality and available ad-lib.
• Do not force cows to clear up poor quality or spoiled forage.
• Encourage maximum saliva production with salt or salt licks and adequate water.
• Sodium bicarbonate (150-200 g/cow/day) can help overcome acidosis but needs to be fed with care, particularly on introduction.
• Ensure the fibre is the correct length (3 – 5cm).
• Ensure the cows aren’t sorting the feed, picking out concentrates.  Techniques to minimize sorting, including frequent feed push-ups, the addition of water or a low dry matter by-product, and appropriate forage processing.
• Maximize feed intake by making sure all cows have sufficient feed space (including heifers).
• In addition, overhauling the dry cow regime to diminish abrupt changes onto the energy dense early lactation diet.
• Try to use starchy feeds that have been processed less and will be released more slowly, e.g. bruised cereals rather than rather than heavy roller.

Displaced abomasum (DA)

The major risk period for DA is 2 weeks before calving through to 2 to 4 weeks postpartum.  Cows with displaced abomasums are typically dull, show a marked drop in feed intake (especially of concentrates) and reduction in milk yield, and reduced faeces. The loss of around 50kg of calf and associated fluids from the body at calving leaves a lot of space for displacement. Fat cows will get DA more often due to low intakes prior to calving.

To help prevent displaced abomasums (DAs):

• Encourage high intake and thus gut fill to reach a maximum within 10 days of calving (see acidosis section); Adjust dry cow feeding to maximize intake in early lactation.  As a high proportion of DA’s are secondary – something else stopped the cow eating first.
• Avoid short-chopped forages.
• Step-up parlour concentrate feeding levels gradually to minimise acidosis.
• Minimise stress by keeping cows in established groups, and parlour and cubicle training heifers before calving.
• Excessive amounts of concentrate during the precalving period increase the risk of DA.
• Minimal intake of concentrate during the prepartum period may increase the risk of left DA through failure to prepare the rumen for the subsequent lactation.
• Ensure cows have access to exercise so that muscle tone is maintained.

Ketosis

The mobilisation of large amounts of body fat in the liver in an attempt to bridge this shortfall can lead to toxic levels of ketones accumulating in the blood, milk and urine. This results in loss of appetite and a marked fall in milk yield.

Over-fat cows with reduced appetites are more prone to ketosis than fit animals.  Ketosis is often associated with fatty liver and displaced abomasums.

The main cause of ketosis is the under-feeding of energy; poor quality forage or a shortage of silage in the winter being major underlying factors.

To help prevent ketosis:

• Aim to have cows fit but not fat at both drying-off and calving.
• Introduce the main production forage during the dry period.
• Introduce other ingredients of the production ration three weeks ahead of calving.
• Formulate production rations carefully to meet balanced energy and protein needs to reduce the extent of negative energy balance.
• Ensure sugar and starch levels do not exceed recommended levels.
• Avoid acidosis by limiting individual concentrate feeds to no more than 4kg at a time.
• Monitor forage quality and ensure good access to forage at all times.
• Avoid sudden changes in the diet.
• When a group of cows is considered to be at particular risk, individuals may be drenched with 0.5 litres of propylene glycol at calving to provide an immediate sugar source that reduces fat mobilisation in the liver.
• Feeding 0.5 litres/head/day of propylene glycol to dry cows in the 10 days prior to calving and as far into lactation as practical – up to 6 weeks – may also be valuable.  Feeding 1 kg/day of ground maize can have a similar effect since it resists rumen breakdown and is absorbed directly as glucose.

Hypocalcemia (milk fever)

Milk fever is primarily a problem of a delay in adjusting from a relatively low demand for calcium to a high demand.  With careful management the incidence of milk fever should be kept within acceptable levels (less than 9% per year).

To help prevent milk fever:

The diet can be manipulated to increase efficiency and absorption of calcium post-calving: –

• Use diets that are low in calcium during the dry period.
• Formulate for high-magnesium diets in the dry period.
• Injections of vitamin D, this isn’t always effective as it has to be done several days before calving.
• The use of minerals acids or acid salts (magnesium sulphate, ammonium sulphate, calcium chloride) for dry cows increases the efficiency of calcium absorption.

Reducing the amount of calcium required in early lactation by partially milking out, care should be taken with this approach due to the risk of mastitis.

Supplying large amounts of dietary calcium: –

• Oral drenching
• Sub-cutaneous infusion of minerals