Exam 3 Review

Feed processing reasons

Improved profitability, mechanization, feed efficiency, and carcass quality/yield grade; to utilize poorly digestible feedstuffs; increase feed intake, digestibility, and average daily gain

Grinding (hammer mill), dry-rolling, reconstitution, steam-rolling, steam-flaking, and pelleting

Roughage processing methods

Pelleting

Feed is finely ground and steamed to improve digestibility; increases bulk density and nutrient density; improves the use of unpalatable, low density, and bulky feeds

Steam-flaking

Feed is steamed (15-30mins) to raise moisture, alter starch granule, and increase digestibility; rolled to produce thin flake; e.g. corn, wheat, barley, and milo

Steam-rolling

Processing method initially used to kill weed seeds; steamed (3-5mins) before rolled; no starch granule alteration

Reconstitution

Increased risk of microbial growth/spoilage; harvested dry and added water; ensiling at 25-30% moisture (oxygen limiting environment); sorghum grain (stored for > days)

Dry-rolling

Steel rollers that crack corn, wheat, and milo into fine powder and flatten barley and oats into fine powder; increases production costs

Grinding (hammer mill)

Most common feed-processing equipment; least expensive production method; disty/less uniform product; reduces feed particle size; source of microminerals (metal friction)

Ruminants; processing can be used to partially counteract the normal decline of digestibility

Feed processing is more critical to what class of animal. And why?

Cold processing

mechanical, physical, or chemical grain treatments performed without heat, including cleaning, dry milling, dehulling, air classification, cold pressing, wet processing, enzymatic treatments, and cryogenic milling

Rumen pH regulation

Acid production, acid neutralization, and acid absorption

Acidosis

caused by an excess of VFAs, excess digestibility, excessive intake of rapid fermentable carbs, inadequate ruminal buffering, and inadequate ruminal adaptation to a high fermentable diet; causes liver abscesses and lameness

Forages vs grains

Ruminants are able to consume forages (no acidosis), but not high-grain diets

21 days

The period of time it takes to adapt to a high-fiber diets

Rumen pH

5.5-7

Low rumen pH

Causes ruminitis, erosion, ulceration of the ruminal epithelium, and chronic health problems

Acidosis pH

Below 5.5 (SARA and lameness)

Particle size and residence time decreases

As surface area, digestibility, and passage rate increases

Ruminal H+

Microbes use H⁺ in methanogenesis, biohydrogenation, and redox reactions; prevents acid buildup and keeps fermentation efficient; saliva + microbes neutralize H⁺

Buffers

Neutralize H⁺ and stabilize pH; protect fiber digestion, microbial health, and animal performance