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Problems which arise as a result of impaired metabolism and nutritional in origin are called metabolic diseases. These problems occur in dairy animals mostly, around parturition. After calving, animal is stressed due to calving, physiological and hormonal changes and increasing milk production. These stress factors further aggravate situation by reducing feed intake and animal goes in -ve energy balance. Animal can't get enough energy required to fulfill its body needs. Besides these problems if animal is not managed properly, it is liable to catch disease which turns out to be a great blow on economy of farm. Once an animal contracts a disease, it becomes more prone to that disease in subsequent lactations as compared to those animals which did not encounter the disease. We can easily avoid these problems through good management. As cost of treatment is extra burden on farm economy. And their management is much easier, doesn't cost much. We can easily avoid or control these diseases by providing balanced rations along with supplements as a prophylactic measure.
These problems are interlinked and chained with each other. A disease acts as a precursor for the other; for example fatty liver disease acts as a precursor for ketosis and these both strengthen grounds for displaced abomasum. Hence, a single disease, due to sheer negligence of management, becomes a syndrome. Once a disease occurs it becomes a future threat. If an animal encounters a disease, he / she fails to give its maximum production even if treated properly, in certain cases.We can prevent occurrence of such diseases by following a golden principle"Care is better than cure". Prepare the animals for future challenge. Through management we equip them for upcoming turmoil. Some of these diseases are 100% fatal, for example milk fever, if it is not treated, it is 100% fatal. But its incidence can be easily evaded by reducing Ca intake or by providing anionic acidogenic diet (-ve DCAD) pre partum in dry period. Fatty liver disease can be prevented by maintaining body score around average 3.5.Interestingly, by taking preventive measures against one disease, other disease itself gets ruled out. Management can save an enterprise from huge losses, so follow the golden rule "care is better than cure".
Nutritional problems that show acute signs and need prompt treatment; occur mostly just before calving to peak lactation. During this time conditions become more favorable because of abrupt change in metabolism from small to large demands of production.Following are the metabolic problems:
1. Udder Edema:
Pooling up of fluid (blood) in udder as calving draws near and near, is called udder edema. It is a normal phenomenon but sometimes it becomes drastic and severe, manifests as excessive swelling around the udder, on udder and teats .It creates hindrance in normal milking and suckling and poses as a risk factor for suspensory apparatus of udder.
Major cause of this problem is impaired or decreased blood and lymph flow from lower abdomen. This decreased flow is largely because of fetal pressure. Sometimes it becomes very severe but gets itself corrected within few days unless aggravated. Other causes include heavy grain feeding and heavy sodium and potassium intake. Owing to these problems UE appears as a herd problem and most serious for first-calf -heifers. Hypoproteinemia is considered another cause for blood proteins are used to make colostrums. Some people don't agree with this idea. Rate of occurrence is different in different situations but it should be less than 3-5% in terms of severe cases that require treatment.
Prevention before calving includes provision of little exercise to animal since it enhances circulation, massage of udder for it improves blood circulation. Sometimes milking before calving is used as preventive measure for it reduces udder pressure. Some people opt for diuretics as well. After calving Prevention after calving, treatment with corticosteroids along with diuretics and sometimes only diuretics also work well. This treatment enhances excretion of fluid through urine. As fetal pressure is the main cause of the problem, induced parturition seems a logical option in very severe cases. Carefully monitor grain feeding and avoid feeding high amounts of salts in late dry period.
2. Milk Fever:
It usually occurs near or at calving.Ca level decreases in blood and muscle become weak. Sometimes may lead to death. It is most common metabolic disease and if not treated well results in other complications like uterine inertia , prolapsed, retained fetal membranes etc.Normal incidence rate is 3-8% and it may become as high as 25-30% and even higher. The rate of incidence is directly proportional to age and parity. It is rarely observed in first- calf -heifers, sporadic in 2nd calf heifers, 3rd calf heifers encounter this problem usually 1st time and up to 6th lactation incidence may be as high as 20%.Why its incidence increase with age and parity? Because as age and parity increase, milk production also increase but Ca mobilization decreases.
Decrease Ca intake in dry period .It is done to initiate Ca mobilization from bones before parturition in order to get copious amount of Ca with increasing milk production to cater the needs. But it doesn't work much as is very difficult to formulate diets with so much low Ca content.
Dietary cation-anion difference has revolutionized milk fever prevention therapy for it is not difficult to adjust cations and anions in diet. Feeding anionic diet (-ve DCAD), in late pregnancy, results in acidosis of blood which causes Ca resorption from bones and increases Ca absorption in gut. This can be done by adding anionic salts such as calcium chloride, magnesium chloride, magnesium sulfate, calcium sulfate, ammonium sulfate and ammonium chloride.
Another strategy to reduce blood pH is by lowering potassium content of diet of a cow near calving. It can be done by withholding potassium fertilizers on fields from which dry cows are being fed.Addition of anionic salts in diet of dry cow in order to counter the effect of high cation level. The target value for close up dry cow rations is +200 to +300 mEq/kg. Poor palatability is the main problem in feeding anionic diet so some palatable item such as corn silage and molasses should be added as well.
Milk fever can also be prevented to occur by administration of vit.D3 and its metabolites in dry cow.20-30 million U/day, for 5-7 days prepartum reduces the incidence. OR Single inj. Of 10 million IU of crystalline vit. D, 8 days before calving, is also effective. After calving diet high in Ca content is required. Synthetic bovine Parathyroid hormone is preferable to vit D metabolites as it causes Ca absorption in gut and Ca resorption from bones as well. But main problem lies in the availability of such products.
It usually occurs in adult cattle in early lactation (1st 6 wks).It is characterized by partial anorexia, depression, nervous dysfunction signs, abnormal gait etc. It occurs when there is excessive adipose mobilization and high glucose demand which are normally present in early lactation because of negative energy balance. In this disease animal refuses to take grains, feed intake is reduced. It is diagnosed on the basis of presence of ketone bodies in milk and urine.
Maintain body condition when cows become too fat. Ketosis can be prevented by maintaining and promoting feed intake because feed intake is reduced in last 3wks of gestation. In late gestation closely observe feed intake and adjust rations to maximize DM and energy consumption. Concentrations of NDF should be 28-30% and non-fiber carbohydrates concentration 38-41%.Supplementation of propylene glycol, calcium propionate, niacin, sodium propionate, and rumen protected choline in the feed is also helpful in prevention of ketosis
4. Downer Cow Syndrome:
In cattle condition of prolonged inability to rise is called DCS. Two days before calving to 10 days post calving are most susceptible for occurrence of this disease. Cows which do not react to Ca therapy two times are termed as downer cows. The main cause of the" downer cow" is recumbence for a longer time (beyond 4-6 hours). Most cows which don't react to milk fever treatment subsequently become downer cows. So mostly it is considered a worsened case of parturient paresis.
Postmortem exam of downer cows shows signs of injury, due to trauma, to heavy muscles and thigh & pelvis nerves. The cause of injury could be dystocia, parturient paresis etc. and it can occur before, after or during calving. Treatment generally doesn't work.40 to 60% mortality rate may be observed. Nursing care is more important than treatment. Animal should be provided enough bedding, diet to eat and clean, fresh water to drink and change the sides of cow frequently (hourly) every day to lessen the damage due to pressure.
Calving cows should be observed carefully and immediately treated when first milk fever signs appear. Calving areas should be clean, rough surfaced to avoid slipping and well bedded. Avoid occurrence of milk fever as most of the time this problem is aggravated milk fever case.
5. Grass Tetany:
It is also called hypomagnesemic tetany, and lactation tetany. It is reported to be highly fatal disease of milch dairy cows. It is characterized by low Mg level in blood coupled with hypocalcaemia in some cases. Affected animals show tonic-colonic muscular spasms and convulsions along with muscular weakness. This weakness is similar to that of milk fevers.
Lush grass with high moisture content (wheat or rye) in the springtime is major cause of this disease. This grass reduces magnesium (Mg) absorption. This problem can also occur when concentrations of Mg are low as compared to other minerals .If the loss of Mg in milk, urine, digestive secretions, and sweat is copious, hypomagnesemic tetany may occur. This is due to, more loss of Mg than its dietary intake.
Earlier signs are similar to milk fever. Other signs include, muscle twitching, grinding of teeth, excitement, convulsions, and high salivation etc.
It shows more vigorous nervous signs than milk fever because of Magnesium, being the 2nd most abundant cation in fluids present inside the cells (to K+) and the activator of many nervous system enzymes .These enzymes are likely to cause more nervous, excitable symptoms than Ca tetany.
Its response towards treatment is quick and dramatic. Milk fever and grass tetany recover both with the same treatment because most "milk fever" treatments contain Mg also.
Pastures which are heavily fertilized (wheat, sometimes called wheat pasture poisoning) have been found involved in this condition. Supplementation of Magnesium oxide can help us improve this condition. Mg should be 0.25% of total diet DM.
6. Fat Cow Syndrome:
In early lactation it increases risk of metabolic, infectious, and reproductive disorders especially parturient paresis, ketosis, and retained fetal membranes. It is recognized by the presence of very fat cows in the dry period and too much thin cows in the early lactation. Feeding practices which cause over conditioning in dry cows are the main cause. In early lactation fat accumulates in liver which is a normal phenomenon. Sometimes too much fat gets stored in liver and impairs its function and in few cases leads to liver failure. Such cases generally do not respond to treatment and end up in the death of the animal. In such cases mortality is as high as 50%.
Monitor and manage body condition of dry animal so that cows reach calving in proper body condition. After calving, try to maintain high levels of energy intake in high producing animals. Immediate treatment in early postpartum disease helps to reduce off-feed time and thus reduces the energy deficiency risk.
7. Displaced Abomasum:
It is basically of two types; left side DA and right side DA.
Left side DA:
Normal location of abomasum is on the right side of the floor of abdomen. LDA is a movement of the abomasum from its normal position to the left side of the abdomen .It gets located between the left wall of the abdomen and rumen. During 1st month of lactation its incidence is vey high and reaches up to 80%. A few cases have also been reported before calving. Mostly, animals, that produce milk in very high quantity, are the victim of the disease. Incidence is higher in older cows than in first-calf heifers.
Feeding of grain, in very high quantity near calving and in early lactation, is the main cause of this problem. Corn and corn silage are good examples that contribute to its incidence. Grains produce VFAs and decrease the movement of stomach and intestines. If the production of VFAs is very high then some unabsorbed VFAs accumulate in the abomasums and lessen its movement by acting on its smooth muscles. VFAs are also produced as a result of feeding concentrates. Feeding too much concentrates increases the flow of ingested feed to abomasum and it gets stored there. It causes gas production and inflation of abomasums which ultimately results in displacement of abomasum. Some people consider parturition the main cause of this problem.
It normally occurs within a week after calving. Cows become off feed, drop milk production and show signs of ketosis with normal temperature. Abomasun is visible from outside in very severe cases when it is distended too much. It appears as a bulge on left side under last rib.
Loud "ping" by striking over the 9-12th ribs at the same time and listening the sound with stethoscope above last rib region and flank area can be helpful in diagnosis.Treatment usually requires surgery.
Right-side displacement of the abomasum (RDA) and abomasal torsion:
Abomasum becomes dilated due to accumulation of gas and fluid. Sometimes it leads to twisting of abomasums which resultantly completely blocks the GIT. Animal feels very severe abdominal pain, becomes off feed. This complication has a very high mortality rate. It incidence is very low as compared to LDA but causes are same for both complications. Both of these are different from each other only in terms of positioning of abomasums after displacement. Their signs are similar so their differentiation is very difficult clinically. Sometimes distention of abomasum is visible on right paralumber fossa. And ping can be heard on right side percussion. Immediate surgery is option for treatment. Consequently, keeping these diseases to a minimum will aid in reducing the incidence of abomasal displacement.
Prevention of DA:
Avoid over conditioning of cows as over conditioning is a likely cause of DA. High concentrate feeding before calving can cause DA, so it should be avoided. it should be enough to maintain body condition and ration should contain more roughage. If there is less space at feeding bunk, overcrowding , difficulty in feed access and animal is uncomfortable, this can lead to less feed intake ,low rumen fill ,more chances of migration to abomasums and ultimately DA. Physical form of feed matters a lot as too small particle size can cause DA. Small particle size leads to less chewing which results in less rumen fill and more GIT motility, and more VFAs production and ultimately DA. Properly manage other calving-related disorders ultimately reduce risk of DA. Sudden dietary changes should be avoided as it lead to low feed intake.
8. Retained placenta:
It is defined as failure to expel fetal membranes, after parturition, because fetal villi can't detach from the caruncles of mother. Its incidence rate is 10%.It is reported in literature that cows which give birth to male calf retain placenta for longer time. Premature birth and certain diseases are considered as contributing factors of retained placenta. Other causes are Vit A and Selinium deficiency, Cu and Iodine deficiency. Its recurrence rate is 20%.Its treatment is done by infusion of intrauterine antibiotics and sulfonamides. Sometimes warm water is also infused intrauterine as it causes the release of prostaglandin and relaxin and release afterbirth. Pre partum injection of Selinium at low doses reduces incidence. Supplementation of Selinium and Vit E in deficient areas. Don't cause Vit A and fiber deficiency. Avoid over conditioning.
Management not the treatment is the ultimate solution of metabolic disorders. Dry period management is the critical one in this regard. Efforts should be made to prepare animal to face critical period after parturition. As feed intake is reduced to almost 30%, so try to maximize feed intake in early lactation. In other words increase DM intake. Adopt preventive and prophylactic measures to avoid incidence of any metabolic disorder. Give glucose precursors to prevent from ketosis. Combat -ve energy balance period and try to bring the animal in +ve energy balance. Provide -ve DCAD diet to avoid milk fever. Monitor and maintain body score around 3.5.Avoid feeding too fine particle size diet as it may lead to decreased GIT motility and displaced abomasum. Don't feed heavy grains and concentrates in dry period. Provide balanced rations for protein and energy both. Avoid abrupt dietary changes without proper rumen preparation.