Toxemia of Pregnancy in Sheep - Article Example

TOPIC: PREGNANCY TOXAEMIA IN SHEEP By student’s Name: Code+ Course: Instructor’s Name: University Name: City, State: Date of submission: Abstract Pregnancy toxaemia occurs when there is a significantly low level of sugar (glucose) present in the blood. The reduction in the glucose level results in brain damage, dehydration, failure of kidney and finally may lead to demise. It mostly occurs in the final weeks of pregnancy and its usually due lack of adequate nutrition. Especially in Western Australia during autumn, ewes are vulnerable to pregnancy toxaemia since there is shortage of dry feed to meet their increasing nutrition demands. Ewes in late pregnancy are the most vulnerable as well as those carrying twin lambs or triplets (Berry 1976). Introduction In the recent past, forage has been the major and cheapest amongst sheep diets. However, farmers embark on usual natural grazing on pasture when the price of concentration ingredients rises. Practically, it’s next to impossible to attain the required metabolisable energy needs for survival and pregnancy in ewes. During pregnancy, energy requirements of ewes should be raised by 20% which cannot be purely obtained from natural pasture. Pasture grazing is associated with negative energy, feed restriction state as well as nitrogen balance in ewes during their late pregnancy even though sheep are characterized by seasonally oestrus cycle. In Australia, winter is the lambing season and it associated with decrease in food quality. Therefore, a sheep whose energy is negative and is in protein balance requires grazing on poor pasture or be fed on low quality hay and stand diverse levels pertaining to food restriction. An early embryo usually does not require so much energy from the mother but on the other hand it may greatly impact on metabolic responses of the mother regarding to nutritional requirements at various stages during the period of early pregnancy (Hawkins and Morris 1978). Pre-partum and post-partum associated problems, animals’ nutritional status assessment as well as metabolic diseases are diagnosed and predicted using metabolic profiles. For instance, blood glucose is the main metabolite used by the foetus leading to increase of energy requirements of the ewe as the foetus grows rapidly. Cause The major cause of pregnancy toxaemia is the abrupt demand for energy by rapid growing lambs usually during the last few weeks of pregnancy. However, the disease is not prevalent to ewes carrying singles but susceptible to those carrying twins. Increased demand for energy and protein is the major cause of the disease in the event where the ewe is not adequately fed. This leads to malnutrition and hence the ewe lacks necessary energy to support its maintenance and the survival of the lamb. Therefore, there is need to increase feedstuff with high volume of energy for the upkeep of the foetus. Ewes consuming huge amounts of hay require larger internal space in the rumen and this reduces the space for better growth of lambs in the uterus (Rook 2000). In case where the ewe meets the required nutritional needs for the support of the lamb, it will metabolize its fat resources in the body in order to maintain pregnancy. This hasty process of energy store breakdown produces ketones – a toxic product and the disease symptoms starts to be noticed. Maintaining ewes at medium body size rather than being too fat minimizes the chances of pregnancy toxaemia. However, it’s worth noting that feed restriction may have adverse effects on ewes carrying single lambs and may cause pregnancy toxaemia. Transmission The disease is not transmittable form one ewe to another, however, flocks experiencing the disease may have similar characteristics and it may seem to be infectious due to similar conditions of inadequate nutrition. Energy inadequacy in the diet many have similar effects on ewes carrying twins or triplets (Berry 1976). Foetuses developing in multiples may cause terrific nutritional drain during the ewe’s late pregnancy stage. Her failure to eat due to adverse weather conditions or stress may lead to fall in the level of glucose in the blood and this may accelerate plasma ketones. Symptoms Ewes affected by pregnancy toxaemia usually separate themselves from the rest of the flock. Since the ewes become blind or almost blind they are quite sensitive to sound though they seem reluctant to move. In case of any danger they may not be able to escape. They may sometimes circle, shake or quiver, bang into objects, neck twisting and raise their faces up as if they ate ‘gazing at the stars’. More often than not they are in coordinated and they may usually stumble and fall and might go into convulsions. Drowsiness is normally a common phenomenon during convulsions (Sykes, Coop and Ruston 1980). Feaces on the other hand are dry and scanty. Ewes may also be noticed grinding their teeth. Those that might not be treated may be unable to rise for about three to four days before they finally die. There may also be detectable smell of ketones which is usually sweet/ foul when the ewe is breathing. Ewes that are almost lambing may become weak, have difficulties in giving birth and there is risk of death to the lamb. However, death of the lamb may happen in the uterus reducing the glucose requirements for the ewe but this might cause relapse due to toxaemia from the already decomposing lambs. Presence of low sugar in blood, ketones increase in urine as well as in blood is notable characteristics of pregnancy toxaemia. Blood level may however, be observed to fall to 20-40 mg/dl or even lower. Treatment Treatment of pregnancy toxaemia involves eliminating nutritional drain on the ewe – Caesarean section, whenever the symptoms are detected early. Steroids are normally used to reduce excessive pain during labour. Alternatively, propylene glycol may be administered to the mother by the mouth for a number of times during a day usually three (3) or four (4). Molasses, pancake syrup or Karo Syrup may be utilized though in a pinch. Ewes that are highly valuable may be served with intravenous catheter coupled with constant therapy of glycol sugars, lactate ringers as well as sodium bicarbonate solution in order to arrest acidosis (Rook 2000). Diagnosis of this disease depends on the symptoms, history of the disease, high ketones, necropsy findings and clinical tests that shows low levels of glucose. However, if the disease is detected early glucose may be used to treat ewes usually (30-50cc of 50%) and respond positively although the glucose used may not have an impact on the negative nutritional balance. Prevention Prevention of pregnancy toxaemia may be less costly as compared to curing. As the general sheep husbandly continues to improve day in day out, there is need for the farmer to be sensitive of breeding dates. Determination of ultrasonic pregnancy will be better by far and may be the most accurate method of identifying ewes carrying multiple births to save the mother from pregnancy toxaemia in early stages of foetus development. A keen sheep farmer ought to discover twins or triplets in early stages of pregnancy in order to adopt the best feeding practice for the mother and provide her with sufficient nutrients required for the maintenance of the lamb. The farmer needs to increase the nutrition level during the last six (6) weeks of the gestation period. However he/she needs to watch out in case the ewe is carrying a single lamb. He may feed the ewe and later on it develops complications during birth to overgrown foetus. Sudden change in quantity as well as the quality of feeds may be avoided in order to prevent the disease. In cases of bad weather extra feeds may be provided to the ewe for it to generate adequate energy for its survival and the maintenance of the foetus (Sykes, Coop and Ruston 1980). Excellent pasture supplies the sheep with adequate energy and proper exercise which is important for its health. Regular exercise in sheep helps in proper blood circulation and it’s also crucial for body tone. In pregnancy toxaemia diagnosis there is production of three main ketone bodies which are later analysed for its diagnosis (Van 2000). They include; Beta- hydroxybutyrate (BHB), acetone and acetoacetate. Among the major three ketones, BHB seems to be the most stable presence in the blood and takes up to 85% of all ketones in sheep and goats experiencing the disease. Thus, ketones do receive reasonable attention in the laboratory. Laboratory tests on individual ewes may be characterized with increased urine ketones level, increased BHB levels, hyperkalaemia and hypocalcaemia which may be as a result of ketoacidosis. However, during the early stages of pregnancy toxaemia, there is easy detection of ketones bodies in the urine. Pills and strips tests are normally used to detect the anomalies; they usually contain nitroprusside that will always turn purple due to presence of acetoacetate. Also plasma as well as the serum can be tested using ketones strips or powders. This may be the case where the affected ewe is dehydrated and urine may not be available to test for ketones (Hawkins and Morris 1978).   References Berry C.I. and Dargie J.D. 1976, ‘The role of host nutrition in the pathogenesis of ovine fascioliasis’. Veterinary Parasitology, vol 2, pp: 371-332. Hawkins C.D. and Morris R.S. 1978, ‘Depression of productivity in sheep infected with Fasciola hepatica’. Veterinary Parasitology, vol 4, pp: 341-351. Rook J.S. 2000, ‘Pregnancy toxaemia of ewes, does And beef cows. The veterinary Clinics of North America.’ Food Animal Practice, vol 5, pp: 293-317. Sykes A.R., Coop R.L. and Rushton B. 1980, ‘ Chronic subclinical fascioliasis in sheep: Effects on food intake, food utilization and blood constituents.’ Research in Veterinary Sciences, vol 28, pp: 63-70. Van Saun R.J.2000, ‘Pregnancy toxaemia in a flock of sheep. Journal of American Veterinary Medical Association,’ vol 217, pp :1536-1539. Read More