Exam Notes - Section 1

Exam Notes - Section 1 - Essential elements of feeding...

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Unformatted text preview: Essential elements of feeding system management Combine feed and feed delivery resources most suitable to particular farm. Make decisions before the first cow is fed Forages - High fiber feeds- Goal GROW OR PURCHASE? Maximize dry matter yield, nutrient yield/a, palatability, digestibility, minimize risk, least cost/unit of nutrient. Supplemental feeds Supply nutrients missing in the forages at lowest cost with highest palatability. Buy what you need! Delivery System Milking herd – optimize intake of early lact. cow. Provide environment conducive to control of ration intake - Energy Many alternatives What system is best suited to forages, supplemental feed, facilities, preferences Ration formulation comments By hand? Many systems out there DAIR4 SPARTAN CPM NRC Amino Cow Dalex PCDairy Practical recommendations Ease of use. New NRC recommendations Our objective for ration formulation software - Develop practical, economical rations with nearly any system. Newer systems are more sophisticated Enable more accurate formulation Can I deliver this more accurate ration and have the cows eat it as intended? Do I have the analytical information to use these more sophisticated systems Rumen Function o Provide an environment for the microbial fermentation of complex carbohydrates o VFA – energy source for ruminant – acetic, propionic, butyric acids o Microbes – protein – amino acid source o Yield influenced by energy supply o B vitamins o Symbiotic relationship Ruminant Anatomy o Reticulum – 10 liters o Rumen - capacity 160 - 240 L o 40 – 60 gallons o Omasum – basketball size – 5 – 8 L o Abomasum - 5 - 8 L Rumen Papillae o Increase surface area o absorptive capacity is 2x VFA production o Remove products of digestion o Buildup of VFA o inhibit fermentation – why? o decrease passage rate - why? o decrease intake Products of Fermentation o VFA o Acetate o Propionate o Butyrate o Microbial protein – amino acids o B vitamins o Carbon dioxide and Methane o Ammonia and Nitrate Rumen Motility o Primary Contraction - Mixing cycle o functions to move - turnover digesta o Timing o Rest - 28 sec o Rumination - 26 sec o Eating - 23 sec o Secondary Contraction - Eructation cycle o 1:1 ratio for primary to secondary Factors Effecting Contractions o Physical form of diet o High forage - 70/hour (primary) o Low forage - 55/hour o No forage - 45/hour o Rumen pH - 6.5 to 7.0 optimal for # o pH <5.5 contractions and motility decline o pH <4.5 motility ceases o VFA concentration – chemoreceptors Benefits of Rumination o Increases feed intake o Reduces feed particle size o Adds saliva – so? o Prevent or reduce rumination slower fermentation rate o decrease passage o decrease intake Saliva o Cattle consuming a forage diet - 180 L/day o Functions o aids in mastication and swallowing of feed o buffering o An excellent buffer between pH 5.5 - 7.5 o Small particle size reduces saliva during eating and rumination Needs of the microbes o Readily available source of CHO...
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This note was uploaded on 03/30/2008 for the course DASC 3274 taught by Professor Rejames during the Fall '07 term at Virginia Tech.

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Exam Notes - Section 1 - Essential elements of feeding...

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