The effect of chop length of hay on the rumen and intake levels in - - PowerPoint PPT Presentation

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The effect of chop length of hay on the rumen and intake levels in - - PowerPoint PPT Presentation

Feb 05, 2023 649 likes •831 views

The effect of chop length of hay on the rumen and intake levels in sheep Brooke White BVSc/BVBio (Hons) Acidosis Acidosis: rumen pH falls below 5.0 and lactate producing bacteria predominate. Sub-acute rumen acidosis (SARA): rumen pH

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The effect of chop length of hay on the rumen and intake levels in sheep

Brooke White BVSc/BVBio (Hons)

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Acidosis

  • Acidosis: rumen pH falls below 5.0 and

lactate producing bacteria predominate.

  • Sub-acute rumen acidosis (SARA): rumen

pH falls to between ~6.0 and 5.0 and there is an increase of volatile fatty acids in the rumen

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Volatile Fatty Acids

  • Microbes in the rumen ferment carbohydrates into

volatile fatty acids which are absorbed through the rumen wall into the blood stream.

  • Volatile fatty acids are the main energy source for
  • ruminants. They are used primarily by the

microorganisms for reproduction and growth, with the excess production being used by the ruminant itself.

  • The three main volatile fatty acids produced in

ruminants are acetic acid, butyric acid and propionoic acid

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They CHEW! How do they counteract the acid production?

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What Do We Already Know?

  • Dairy industry – well established guidelines
  • Sheep industry – no published studies regarding chaff
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The Trial

  • 24 wethers
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  • Three treatment groups – long, medium and short.
  • .
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Samples

  • Rumen fluid pH and VFA

concentrations measured for three days.

  • Intake of chaff and grain

measured for ten days.

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What did we find?

  • No difference in pH
  • Some significant differences in VFA

concentrations.

  • Significant differences in intake at 3

hours and 24 hours after feeding.

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Rumen pH

5.60 5.80 6.00 6.20 6.40 6.60 6.80 7.00 7.20 7.40 7.60 Pre feeding Post feeding chaff only Post feeding grain day 1 Post feeding grain day 2 Post feeding grain day 3 Rumen pH Time Long Med Short

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Total VFAs

10 20 30 40 50 60 70 80 90 Pre feeding Chaff Grain day 1 Grain day 2 Grain day 3 Concentration mmol/L Sample Time Long Medium Short

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3 Hour Chaff Intakes

  • 0.05

0.05 0.1 0.15 0.2 0.25 0.3 0.35 Grain day 1 Grain day 2 Grain day 3 Chaff eaten (kg) Sample Time Long Medium Short

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Daily Chaff Intakes

0.2 0.4 0.6 0.8 1 1.2 1 2 3 4 5 6 7 8 9 10 Intake (kg) Experimental Day Long Medium Short

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So What Does This Mean? Short Eat it Good pH Good VFA levels Medium ×Eat it ×Lowest pH OK VFA levels Long Eat it Good pH Good VFA levels

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So What Do We Feed?

  • Short chaff initially: intake levels
  • Long chaff after grain adaptation: buffering

effects and long term rumen stability.

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Supervisors: Dr Michael Friend & Dr Edward Clayton NSW Department of Primary Industries Charles Sturt University Animal and Veterinary Science Students Acknowledgments: