Technical training session 1 The rumen and the digestive system What are you feeding? Source: Spurgeon’s Color Atlas of Large Animal Anatomy (1999) Where is the rumen? The rest of the digestive tract Source: Spurgeon’s Color Atlas of Large Animal Anatomy (1999) The Digestive tract • Mouth • Rumen & Reticulum • • • • Omasum Abomasum Small intestine Large intestine Saliva • Added in the mouth during eating and rumination • Dairy cow can produce 170 litres a day of saliva (sheep 10 l) • Contains Sodium bicarbonate & Phosphate (pH) and urea (recycling Nitrogen) Rumen • Rumen 200 litres in a Dairy cow • Occupies most of the left handside of the cow Rumen • Food is attacked by microbes, (rumen bugs) mixed generated by contractions of the reticulorumen muscle • Anaerobic fermentation vat • Function is maximise microbial fermentation Calf rumen 6 weeks old Rumination/Cudding • When not eating, approx ever minute, regurgitation happens • A large mass of rumen content from the anterior end of the rumen is pushed back to the mouth, any liquid is swallowed, • Coarser material is re-chewed. It can be chewed 40/50 times. Far more than when first eaten • This reduces particle size & mixes Rumination/Cudding • Watch cows for cudding • 50/60% of cows lying down should be cudding • Cudding rate rough 50/60 per minute • Muck Rumination • Ruminant is caused by physical stimulation of the epithelium of the anterior rumen wall • Diets with very low fibre will fail to stimulate rumination • Need Fibre (NDF) • A dairy cow will spend about 8 hours a day ruminating Rumen • Temperature ~ 40C • Anaerobic- no oxygen. Any oxygen entering will be rapidly used • pH 5.5-6.5- maintained by buffers and absorption of nutrients • Absorbed VFA, Water etc VFA absorption • 4kg per day of VFA produced Abomasum • • • • • DA The equivalent of a monogastric stomach Low pH, 1.0-2.0 by secretion of HCl Kills bacteria Enzyme secretion, particular pepsin which starts to digest proteins The rumen mat • Keeps solid at the top • Liquid at the bottom. • Critical to a healthy rumen (fibre) The rumen: what are you feeding? 120,00million, million Good Bacteria digesting the feed (Fungi, Yeasts) Bacteria • Take 2 to 3 weeks to adapt to dietary changes • Different bacteria with different diets Bacteria Need • Need consistency • Need energy and protein to grow • Need a spread of energy release through the day • Need a spread of rumen protein Bacteria don’t want • Changes in diets • Particularly changes in forage types takes 3 weeks to change to forage digestion. Dry cows • Changes in feed materials • Low pH acidosis Feeds in the Rumen – Digestion of fibre (forage) to sugars that bacteria can use. You have to use the forage on the farm for best advantage Balanced Ration Starch Let the cows tell you!!! Fibre New Forage /change of diet etc acidosis Need to ration the cows to balance the ration Perfect muck? Acidosis • Loose muck • Variable muck • Presence of feed in the muck Feeds in the rumen • Fibre slows down the rumen, increases pH fermented to acetate for butterfat and milk and growth • Starch drives the rumen bugs (feeds) produces propionate, lowers pH, good for milk protein and energy milk and growth • Sugar drives the bugs also to buyrate Summary • • • • • • Need to feed the bacteria Bacteria need consistency Cows need consistency Starch for milk yield and growth Fibre for butterfat and rumen matt and health Control rumen pH Balanced Ration Starch Let the cows tell you!!! Fibre
