40 pounds

loss of productivity, treatment and labour costs

However, milk fever may result in uterine intertia, dystocia, uterine prolapse, reatined foetal membranes and downer cow syndrome-> 209 pounds 

fatal costs: 1,655 pounds

calcium is the most important mineral in the body. 99% stored in the skeleton, which in the adult cow, only 10g available in the Extracellular calcium pool. But a 600kg daily needs40-50g for body growth and calf growth, allowing for 70% absorption in the diet. but this will increase at the onset of lactation. 

Given that the cow is losing 20-50g calcium through the milk production, blood calcium must be maintained by Parathyroid hormone ( PTH, calcitriol, calcitonin). therefore a lactating cow, giving 40 litres of milk, required dietary intake of 80g calcium per day, there is a balance in order to maintain the normal concentration of calcium in the blood by absorption through the gut, mobilisation from the skeleton. But these processes take 2-3 days and if they fail, hypocalceamia develops. 

 [image]

Age: heifers-less milk, less ca needed, older cows respond more slowly-more prone to milk fever

Oestrogens: potent inhibitors of bone resorption

Hypomagnesaemia: low magnesium may interfere with release of PTH, ability of PTH to act on target tissues, hydroxylation of Vitamin D3 in the liver

Calcium intake during dry period: low levels stimulate PTH secretion and thus mobilisation of calcium from bone and absoprtion from the gut

Acid base status: metabolic alkalosis predisposes to milk fever

Breed: jersey- fewer PTH receptors

nutritional factors: depressed DM intake of cows at calving and digestive upsets 

occur around parturition, and are progressive over a period of 10-24 hours

intially and progression clinical signs 

loss of appetite, dullness

normal or slightly depressed rectal temperature

initial hypersensitivity, with grinding and muscle tremors, stiffness of legs, paddling of feet, reluctant to move, ataxia

recumbancy, initially in sternal with a laterl kink ( S bend) in the neck then the head resting on shoulder. increased heart rate, dilated pupils, gut stasis ( rumen bloat and constipation) , severe depression 

- Cows become comatose in lateral recumbancy, very weak-> eventual ruminal tympany and or paralysis of respiratory muscles-> death

History: most cows- recent calving, high yielding dairy cows

clinical signs: depression, dilated pupil, constipation and ruminal atony

Response to treatment: IV admin of calcium borogluconate will prodce a clinical response in minutes

Biochem: 

- blood calcium level: normal serum levels 2.2-2.6, fall below 1.5 mmol/l

- blood phosphorous levels: low levels seen, fall below 1. 

- blood magnesium levels: slight increase, but also can be low and lead to problems in calcium homeostasis. 

- majority will have had subcut( takes 3-4 hours) calcium by farmer and have not responded 

- thorough clinical exam

- blood sample for measurements

- admin 400ml of 40% calcium borogluconate by SLOW IV injection via the jugular vein using a flutter valve. will provide 12g of calcium. warm solution to body temperature

- some will admin 400ml subcut to prevent relapse

- remove calf and restriction of milking for 24 hours to prevent calcium withdrawn. 

- TLC

- if not moved in 6-8 hrs, re assess

- if blood sample shows low magnesium, treat with 400ml of 25% magnesium sulphate subcut

- forage component of the diet: 

- magnesium supplementation: low dietary magnesium may be a factor

- prophylactic admin of calcium: drenches, gels or boluses prior to calving

- Vitamin D3 injections- 250mg Vit D3( 8 days prior ) , or alfacalcidol ( 24-48hr prior)  prior to calving. 

- milk withdrawl: no precalving milking, remove calf, no milking out for 3-4 days, check cow for mastitis twice daily. 

- dry cow management

1. dietary calcium restriction during the dry period

2. manipulation of the dietary cation-anion balance

aim to limit amount of calcium in the dry cow diet in the 3-4 weeks prior to calving to less than 50g per head per day. magnesium levels in the diet should be above 40g per day. 

- hard to limit calcium on forage rations during dry period

- there are calcium binding products ( X-zelit)- can be added to the close up dry cow diet to reduce calcium absorption. 

full and partial approach 

metabolic alkalosis predisposes cows to milk fever, as the raised PH prevents PTH from acting on its receptor, thus blocking the mechanisms for absorption. lowering the ph stops this lack of response to PTH and releases of cations( ca and sodium)  from bone. Therefore the difference between the number of cation and anion particles absorbed from the diet determines the acid-base balance of the blood. 

reduce the DCAB to between -100 to -200 Eq/kg DM but increasing the cl and S and or reducing NA and K, inducing a mild metabolic acidosis. 

- anionic salts are often used- but can be potentially harmful. they need to be fed for 2-3 weeks prior to calving and calcium intakes kept high. urine ph( 5.5-6.5) is a useful measure of the success of a negative DCAB ration 

- reduce the DCAB value of the transitional dry cow diet

- use low potassium forages ( such as maize, wholecrop wheat) and increase the anions using magnesium chloride. also alot of DCAB mineral mixes that are added empirically to the diet

last 4-6wks pregnancy

- more common in older sheep

- associated with stressful situations

due to muscular paralysis and are similar to those observed in milk fever in cattle. 

rapid resp rate ( panting) with passive reflux of ruminal contents down the nose- green down the nose

70kg ewe -> 20-40mls of warm 40% calcium borogluconate by slow IV, and 50-100ml subcut injection

- feeding of diets containing adequate levels of calcium, but not excessive quantities that will suppress the homeostatic calcium mechanisms

- reccomended calcium intakes are 5-10g calcium per day for ewes in late pregnancy

- avoid stressful situations