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Ketosis in cattle


moo moo...ketosis?


Ketosis is a fairly common disease among adult cattle, although usually it occurs in dairy cattle. Ketosis typically occurs the first six weeks of parturition.It occurs in dairy cattle because of their inability to intake enough nutrients to meet their energy needs.This can lead to hypoglycemia which is a pathologic state produced by a lower than normal level of glucose.That in turn leads to the formation of ketone bodies from the body and fat stores. Although they are only broken down for energy to used by the heart and brain in the times of low glucose levels. Ketosis is not an immediate thing like many other illnesses, it gradually occurs.


The postpartum period is a critical stage of lactation for a high producing dairy cow. This period is characterized by drastic metabolic changes, immunosuppression, negative energy balance (NEB) and elevated levels of stress, which can lead to increased incidence of diseases and decreased animal efficiency.

At the time of calving and onset of lactation, the animal's nutritive and metabolic requirements are increased about 100 percent partly because of the loss of sugar, protein, and fat in the milk and partly because of the increased metabolic work associated with the production and secretion of milk.

For every 20 pounds of milk produced, approximately 1 pound of glucose, 0.8 pound of fat, and 0.7 pound of protein are withdrawn from the animal. Those withdrawals are from the animal's available resources. If the dietary intake is adequate, the animal remains normal. If the diet is too poor to maintain approximately normal levels of blood glucose and liver glycogen, an imbalance in metabolism develops.This upset is indicated by the existing anorexia (loss of appetite), hypoglycemia, and depletion of liver glycogen. In response to these disturbances, compensatory metabolic adjustments are initiated and tend to correct the imbalance.

The high energy demand during this period of glucose shortage triggers a compensatory process of nutrient partitioning and fat mobilization. During this period of glucose shortage, fat is mobilized as an alternative source of energy. It is used as a fuel for basic cell functions in addition to providing energy to maintain milk production.


Feed intake, or lack thereof, is a critical component in the onset of ketosis. In all cows, dry matter intake begins to decline approximately one month prior to calving, although many people will not notice this decline until several days prior to calving. as feed intake declines and galactopoeisis begins, body fats are mobilized, resulting in an increase in circulationg NEFA levels. NEFAs (nonstrerified fatty acid) themselves are mild appetite suppressants, so they continue to hamper feed intake. NEFAs are also the primary substrate for the production of ketone bodies via ketogenesis. Ketones are potent appetite suppressants, so an increase in their presence also decreases intake.

Once calving occurs, milk production places significant pressure on the liver to supply large quantities of glucose which are required for lactose production in the milk synthesis process, as well as the normal glucose that is required for cellular metabolism. Part of that glucose is utilized as body fats are mobilized and converted back to a readily useable energy form by the liver. If liver function is impaired due to poor prepartum management, then ketosis may result, usually in the first several weeks of lactation. These cows often have a history consistent with adequate to excessive body condition at calving that is then lost very rapidly, often resulting in a significantly thinner cow at the time of physical examination.

Cows with elevated BCS at calving (BCS ≥ 4.0) had elevated levels of circulating ketone bodies in plasma. They were at the highest risk of developing clinical and subclinical ketosis compared to cows classified as either a moderate or thin BCS prior to calving. Ketosis is an undesirable condition with a severe impact on animal performance and consequently on the economic well being of dairies.


Conditions when ketosis is likely to occur

  • Late pregnant cows, ewes and does in the last six weeks of pregnancy grazing dry poor quality pasture (less than 1,000-1,500kg DM/ha), stubbles or green pasture (less than 800kg DM/ha).
  • Fat cows, ewes or does (ie fat score greater than 3.5-4) or light cows, ewes or does on very poor pasture.
  • Twin-bearing ewes or does.
  • Previous history of pregnancy toxaemia.
  • Cold wet windy weather.
  • Extensive grazing situations where the last third of pregnancy coincides with a late break in the season followed by cold weather leading to little pasture growth.
  • Short periods without feed (yarding).
  • Stress (due to climatic conditions, handling, being chased or management procedures).
  • Heavy worm infestation.

Symptoms
  • decreased appetite,
  • marked weight loss,
  • decreased milk production,
  • acetone odor of breath,
  • nervousness,
  • hard, mucus covered feces.

For confined cattle, usually decreased appetite is the first sign that they might have ketosis. Also if they are fed in components such as part forage, part grain, they will tend to go for the forage more than they will go for the grain.If you fed your cattle in herds, then usually you will see reduced milk production,lethargy and an somewhat "empty" appearing abdomen.When cattle are physically examined with having ketosis they may appear sightly dehydrated.


Treatment

IV administration of 500 ml of 50% dextrose solution. This treatment allows rapid recovery but the effects are often producing results beyond itself therefore relapses of ketosis are pretty common.Another treatment that can be used is the administration of glucocorticoids such as dexamethasone or isoflupredone acetate via intramuscular.


In mild cases of ketosis you may give your cow 250-400g/dose of propylene glycol orally. Propylene glycol acts a glucose precursor and therefore may be combine with other treatments and can be administered twice a day. However accidentally overdose cow with propylene glycol it will lead to central nervous system depression.



Prevention

Due to the increased energy demand required before calving, strategies to prevent metabolic diseases must focus on the nutritional management of the dry and transition cow. The goals of these diets are to provide all required nutrients and to adapt the rumen for future diet changes as cows advance through these lactation stages.

To prevent metabolic disorders, diets must be properly formulated to accomplish this goal and to minimize DMI reduction.Managing BCS towards the end of the previous lactation is an important management practice to minimize ketosis and other postpartum metabolic diseases.

Probiotics have been shown to promote a positive appetite in animals during times of stress. Feeding probiotics to cattle 2 weeks prior to freshening can help maintain DMI’s through this phase resulting in a better energy balance. This concentrate of good bacteria can help stimulate the gut and perk the animal’s appetite within a few hours.


Sources: ketosis in cattle: symptoms and treatment, helium.com, understanding and dealing with ketosis probiotic smart.com, ketosis in daity cattle, cattlenetwork.com, dairyketosis; cat.vet.upenn.edu, pregnancy toxemia;meat and livestock australia, ketosis in cattle for animal disease; Joseph A. Dye and Robert W. Doughtry

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