Ruminant Mineral and vitamin metabolism Flashcards
(39 cards)
What is the other name for pregnancy toxaemia?
Twin lamb disease
when does twin lamb disease happen
last 4 weeks of gestation
what is the causes of twin lamb disease
- poor rationing during late pregnancy
- outdoor sheep in poor weather conditions
- ketosis
what is poor rationing during late pregnancy often related to?
Poor ME (metabolic energy) of silage given as feed
What is ketosis
when the body doesn’t have enough carbohydrates for the huge energy requirement, negative energy balance so burns fat and makes ketones- loses weight, unable to support oneself.
Signs of Twin lamb disease
Disinclined to move- often seen as stupidity, anorexia, depression, sternal recumbency ketone bodies disturbed vision constipated Recumbency and death
Treatment of twin lamb disease
(similar to ketosis treatment)
- dextrose (bolus IV admin, 500ml 50% dextrose
- propylene glycol and glycerol drench
- glucocorticoids
Prevention of twin lamb disease
ensure good quality nutrition in the last 8 weeks of pregnancy
supplement rations with hay/ silage or concentrate
which animals are predisposed to this disease?
If they have a BCS of below 2 or above 4, carrying more than one foetus
What is hypomagnesaemia?
Grass staggers/ tetany
magnesium deficiency
What causes grass staggers?
- fresh lush pastures, low in magnesium- we generate lush basil etc for nitrogen uptake, but this may be low in fibre content. This means the rumen passage is faster, and the Mg uptake and other mineral uptake are compromised.
What causes grass staggers (2)?
- Fertiliser (N or K) can reduce the uptake of Mg into pasture- K locks Mg in soil. The plants have lower Mg, therefore disturbance in mg uptake by animals
- first cut silage can be low in Mg
- usually during first lactation, there is a high requirement for mg in milk
What are the signs of grass staggers?
- subclinically= <0.8mmol/L in blood of Mg
- hyper-excitable frothing at the mouth
- muscle twitching and teeth grinding
- dead stock at pasture
Treatment of grass staggers.
animals should not be stimulated
Mg sulfate can be given subcutaneously
hay treated with 60g of Mg oxide daily
What solution of Mg sulfate should be given subcutaneously?
200ml of a 50% solution/cow
Prevention of grass staggers
- General requirements met: 2.5g/kg DM of Mg for lactating cows at pasture
- Know your swards
- Herbage must be dusted with powdered Mg oxide (500g/cow) or sprayed with a 2% solution of Mg sulphate
- mineral licks or slow release boluses on known trouble swards
what should the farmer do to ‘know his swards’?
soil assessment regarding K and Mg levels- since potassium directly effects the absorption of magnesium
minimum calcined magnesite= 1.25t/Ha
What is Cerebrocortical necrosis (CCN)
Also known as Polioencephalomalacia (PEM) Vitamine B1 (thiamine) deficiency
cause of CCN (1)
Rapid change in plane of nutrition, poor to high quality, which leads to subclinical lactic acidosis and hence an alteration in ruminal microflora
reducing production of B1
cause of CCN (2)
destruction of B1 within the rumen and gastrointestinal tract
excess Sulfur in diet
where can you get thiaminase from?
Bracken fern or produced by gut bacteria
Signs of CCN
- nervous disease resulting in necrosis of brain tissue
- circle, blindness, convulsions, collapse, leg-kicking and death
Treatment of CCN
Early Administration of thiamine may cure this, but if the lesions are more advances then the animal is likely to remain partially blind or mentally dull
How to prevent CCN
- Diet formulation to ensure no SARA, regulate amount of roughage in diet
- prophylactic administration of vitamins
- check bracken fern levels in field
- check possible fonts of S excess
