Definition Acidosis A id i – Causes, C Prevention and Treatment Known also as grain poisoning, poisoning grain overload, engorgement Geoff Duddy Extension Officer (S&W) Industry & Investment, NSW Definition VFA Percentages as pH Falls Acetic acid Butyric acid 70 With rapid carbohydrate fermentation Propionic acid Lactic acid 60 50 – rumen acid percentages change – increasingly more lactic acid is produced – rumen and d bl blood d pH Hd drops – rumen buffering capacity is weakened – fermentation efficiency drops 40 % 30 20 10 0 7 6.5 6 5.5 5 4.5 pH 1 VFA Percentages as pH Falls Normal rumen pH range 70 60 Grain 50 % Fibre digesting bacteria 40 preferred range 30 Grain Starch digesting 20 bacteria preferred range 10 0 7 6.5 6 5.5 5 4.5 pH Causes Causes Acidosis is generally associated with – feeding grains or – pellets but may also occur when sheep consume – by-product feeds (eg potatoes) that are low in fibre, high in starch ‘Sugar’ Sugar acidosis may also occur : • on rapidly growing pastures high in sugar but low in effective fibre • when feeding high quality, short chop h acidic idi ((pH H values l <4.5) 4 5) silage il 2 Clinical Engorgement and acidosis leads to: An inability to remove gas and foam Clinical acidosis symptoms usually develop within 6-8 hours. Symptoms may include: • dehydration, • depression • scouring, • coma and death Sub-Clinical Sub-Clinical acidosis symptoms: • dehydration, d h d ti • abdominal pain, • scouring, • lameness,, • abscess’s, • pneumonia Pressure build up Asphyxiation Sub-Clinical • reduced fibre digestion • reduced d df feed d iintake t k • reduced feed conversion efficiency • reduced efficiency overall Sub-clinical acidosis is generally of greater economic importance Sheep Characteristics Sheep differ from cattle with feed passing quicker through the rumen Sheep tend to have a higher incidence of gut issues O pasture On t sheep h spend dh half lf th the ti time eating compared to cattle, but almost four times longer chewing 3 Indicators of ruminal acidosis Indicators of ruminal acidosis Chewing activity – While resting 40 to 50% of a flock should be ‘ h i cud’ ‘chewing d’ Faeces (remember the 3 “C’s”) – Colour, Consistency and Content green when g graze fresh pasture, p , • dark g • brown-olive with increasing hay intake, • yellow-olive with increasing grain intake and • grey generally indicates acidosis Solid Poor consistency consistency, gas Adequate fibre bubbles, intact grain, mucin No acidosis casts etc are signs of acidosis Feed characteristics – acidosis risk g greater when • pasture is lush, leafy and growing rapidly • feeding high quality, low pH silages • inadequate chop length (reduces chewing rumination and saliva) chewing, • feeding processed grain • high starch, low fibre by-products Indicators of ruminal acidosis Laminitis/lameness 4 Indicators of ruminal acidosis Laminitis/lameness Due to increasing blood and pressure in extremities leading to blood vessel damage and swelling Prevention of ruminal acidosis Effective fibre = formation of a ‘rumen mat’ • Adequate and ‘effective’ fibre Lam na damage (hooves), infection Lamina nfect on and increased temperature within affected feet Prevention of ruminal acidosis • Gradual adaptation to starch-rich feeds • Do not crack or grind grains for sheep Bentonite    • Include one or more of following within a ration:  Feed Additives a clay l that th t sswells lls in size si when h n in contact with rumen fluid binds acid ions and slows gut flow negative affect on protozoa which increases protein availability some palatability and digestibility concerns Bicarb of Soda     Feed Additives an n alkali lk li naturally produced by lamb when chewing (in saliva) buffers against acid production add 1-2% 1 2% on weight basis 5 Acid Buf      calcified seaweed honeycombed with large surface area that buffers for an extended period absorbs 3X more acids at pH 5 than bicarb of soda releases l calcium l i and d magnesium i within the rumen add 1-2% on weight basis Virginiamycin (Eskalin)    Feed Additives Feed Additives an antibiotic b prevents multiplication of lactic acid producing bugs require q veterinary y approval pp (S4) ( ) Limestone     a calcium l i m supplement s ppl m nt has some buffering action in small intestine may reduce intake add 1-2% 1 2% on weight basis Yeasts   Feed Additives Feed Additives may aid id in i the h binding bi di of f ‘bad’ ‘b d’ bacteria within the rumen, reducing the risk of acidosis and/or stimulate rumen bugs, increasing efficiency of digestion Feed Additives Ionophores (eg: Bovatec)      increases in s s propionic p pi ni acid id = energy n prevents coccidiosis improve feed conversion efficiencies may reduce intake i l d d att 25 included 25-70g 70 per ttonne of f feed f d Treatment of ruminal acidosis – feeding hay to stimulate saliva flow – antacids (magnesium hydroxide, hydroxide magnesium oxide or sodium bicarbonate) at 1 g/kg body weight – oral electrolyte solutions, ght vegetable oil o l may help sheep – use of llight to belch captured gases, reducing early stage losses 6 Treatment of ruminal acidosis – antibiotics may reduce liver damage – drench with a 1:8 dishwashing liquid/water solution (10 ml/kg) – treat with activated charcoal (if available) - 1-4 g/kg with 1g/50 ml water – Stale beer (rate unknown…..) unknown ) Pre-Training Lambs There are benefits associated with ‘prep training’ lambs while with their dam or experienced ewes to recognise grain and feeders prior to weaning Pre-Training Lambs Training g lambs m to recognise g grain and g feeders • improves future recognition and intakes • reduces shy feeders and • may reduce acidosis risk 7 Percentage Eating (Days 1 and 5) Pre-Training Lambs 100 90 Many store lambs may not have been imprinted and are being introduced to a feeding regime to which they are not accustomed. 80 70 % 60 50 40 30 20 Day 5 Day 1 10 0 Control No Dams With Dams This increases the risk of variable intake, engorgement and acidosis Green et al (1984) 8