The transition period is defined as the four weeks before and after calving, and is characterised by a greatly increased risk of disease. Cows are typically at greater risk of disease as they adapt to the demands of late term pregnancy and milk production.

 

The Importance of the Transition Period

Improved transition cow management has resulted in some of the most significant advances in dairy nutrition and production world-wide over the past 20 years; providing a major opportunity to improve cow health, milk production and reproductive performance. The transition period is defined as the four weeks before and after calving, and is characterised by a greatly increased risk of disease. Cows are typically at greater risk of disease as they adapt to the demands of late term pregnancy and milk production. When the cow fails to adapt adequately from a non-milking to a milking animal, diseases may result.

 

Transition cow diseases include:

• Milk fever (low calcium) and downer cows;
• Grass staggers (low magnesium)
• Ketosis and fatty liver
• Udder oedema
• Abomasal displacement
• Retained foetal membranes (RFM)/metritis
• Poor fertility and poor production. 

Transition Feeding

In recent years it has been discovered that all metabolic dysfunctions such as milk fever, grass staggers and ketosis are linked. As a result of this increased understanding, the concept of transition feeding has evolved from one focused only on control of milk fever to an integrated nutritional approach that optimises:

• rumen function
• calcium and bone metabolism
• energy metabolism
• protein metabolism
• immune function.

Nutritional deficiencies during the transition period will likely affect lactation, animal health and reproductive performance. The transition period is a brief but critically important period in a cow’s life where careful manipulation of the diet can impact substantially on subsequent health and productivity.

In light of this knowledge, it seems logical to split your ‘high risk’ springer and colostrum cows from the rest of the herd. Typically, springer cows will struggle to consume their ration in the time that other cows, in earlier stages of pregnancy, are able to. This means that if they are mixed with the herd, they may be at risk of nutritional deficits, right at the time when you want to protect them from disease. Forming a separate springer mob allows these animals access to the best nutrition to consume at their leisure! It is also necessary to avoid calcium supplementation to cows in the last 3-4 weeks of gestation as they need to mobilise their own calcium stores pre-calving. In contrast, colostrum cows may require calcium supplementation to meet the demands of early lactation. This is just one example of how the nutritional demands of the springer cows and colostrum cows differ. If you would like any advice on how to best manage the transition period in your cows, have a chat with your Anexa veterinarian who can help you develop the best plan for your farm.

 

Milk Fever

Milk fever (or hypcalcaemia) is the result of a reduction of blood calcium usually seen in the early stages of lactation. This is due to the cow having a sudden, dramatically increased demand for calcium to produce milk. It is during this transition period that cows are prone to classical milk fever. Cows that are further into their lactation are better able to cope with the shortfall of calcium by absorbing it from their bones and also the mechanisms by which calcium is absorbed from the diet are working much more efficiently.

Subclinical;  Retained foetal membranes (RFM’s), reduced appetite problems associated with reduced food intake. Remember cows don’t necessarily have to be recumbent to be suffering from low grade milk fever.

Clinical; Recumbency, ‘S’ shaped neck, dry faeces, cold, lack of cudding, bloating – eventually death. These are your classical cases. The cow is down and unless treated promptly can progress to death. The longer a cow is down, the more likely she will develop secondary problems such as muscle damage which can make her less likely to recover fully. Diagnosis is generally based on clinical signs. Blood samples are often taken to analyse later if there has been no improvement – however, blood samples are not much good if taken if supplemental calcium has already been given as this will give confusing results.

Treatment:  Calcium is injected subcutaneously and/or intravenously. Take care not to overdose as this can cause heart failure. Always give intravenous calcium slowly and monitor the cow carefully and stop injecting if you have any concerns. The cow will tremble and may begin cudding if treatment is successful. Not all cows will get up straight away. Be careful when giving multiple bottles of calcium under the skin and into the vein – there is a risk that this may actually raise the blood calcium to too high a level which can cause death in some cases. Discuss with your vet the best treatment protocol for you on your farm.
Prevention: The basic aim when preventing milk fever is to adequately prepare the cow for a sudden increase in requirement of calcium when she calves and begins to lactate. Feed a low calcium diet 4 weeks prior to the planned start of calving to encourage the calcium regulation mechanisms to kick start early. You are basically trying to trick the cow into believing that she is in a state of low calcium during a relatively safe period for her to be in this state (her calcium demands are low at this stage). That means no calcium supplementation at least 4 weeks prior to calving.

1. Check the magnesium status of your dry cows and supplement them appropriately. However, don’t over supplement as this can inhibit calcium absorption.

2. Monitoring of the cows with blood samples during the dry period will help highlight some potential problems.

3. Using a DCAD diet – This method slightly acidifies the rumen which in turn produces an environment which supports optimum calcium absorption from the diet. This is effective but requires careful monitoring. Discuss with your vet or nutritionist if you are thinking about trying a DCAD diet. Milk fever problems can be tricky to resolve and often require dietary changes that can take weeks to show results. It is better to prevent a problem if at all possible.

 

Grass Staggers

Cause:  Grass Staggers or hypomagnesaemia occurs when the intake of magnesium is not enough to sustain the cow’s daily requirements for milk production and muscle activity. The clinical signs can occur very quickly because the cow does not store magnesium, and is thus reliant on its daily dietary intake. Hypomagnesaemia is most commonly a disease of lactating cows at grass, because grass can be very low in magnesium and the output in milk is high. Like most nutritional diseases, the animals showing clinical signs are just the tip of the iceberg, for every cow with obvious disease many more will be affected sub-clinically. The increase in disease in spring occurs because rapidly growing grasses, particularly ryegrasses, are very low in magnesium. Putting potash onto pastures in the Autumn can also exacerbate the problem. Low magnesium levels not only cause grass staggers but can also cause milk fever since magnesium is necessary for calcium homeostasis.

Symptoms:  Restlessness, staggers, over-alert appearance, excitable, or aggressive. Animals may fall down and go into convulsions. In many cases animals may die without any prior sign of disease

Treatment:  Treatment must be prompt to be effective. Veterinary attention should be sought. It is best to inject a magnesium solution under the skin in the area behind the shoulder and over the ribs. Massage the area well after injecting the solution to spread the fluid and aid its rapid absorption into the blood stream. In some cases, repeat treatment may be needed.
Prevention Daily supplementation with magnesium should be given to the whole herd starting at least 4 weeks prior to calving and continuing until at least November. This is usually through dusting of pasture or meal daily with magnesium or drenching daily with magnesium. Discuss your farm specific strategies with your veterinarian.

 

Ketosis

Ketosis typically occurs in the first six weeks post calving. It occurs in dairy cattle when their energy demands exceed their energy intakes. This lack of energy reduces their blood glucose levels which forces the body to use energy from fat reserves. Using fat as an energy source leads to the formation of ketones in the blood and hence the term ketosis. Some typical signs of cattle with ketosis are nervousness, chewing on strange things such as concrete and rails, decreased appetite, marked weight loss, decreased milk production, acetone odor of breath, and hard, mucus covered faeces.

Treatment for ketosis in cattle is commonly done by IV administration of a dextrose solution. Oral drenching of a starter drench, molasses or monopropylene glycol (eg Ketol) may also be helpful in mild forms of the condition. Treatment often has good results in a more sustained response and you may repeat it daily as necessary. Ketosis can be prevented in your cattle by maintaining their nutritional needs. To see what your dairy cow requires to prevent ketosis, you should consult your veterinarian or nutritionist.