Week 4

Roughages

Crop Residues

Text Transcript

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• Various regions, large quantities available as feedstuffs
• Type varies by location
• Examples of residues
• Straws, stover, hulls, and standing feeds
• Decision to feed requires consideration for following factors
• Nutritional value
• Collection, storage, treatment, transportation
• Feeding
• Availability
• Economics
• Grazed, processed as dry feed, and silage
• Also used as bedding and soil amendment
• Nutritional value
• In general, low-quality roughages
• Low digestibility, low CP, low DE, high structural CHO, high lignin, low mineral content and digestibility, low vitamin content
• Table 7-38 on page 160 – Nutrient content of various low-quality roughages
• Also compares nutrient content of low-quality to few high-quality roughages
• Feeding characteristics
• Low palatability
• Low density
• Nutritional value and feeding
• Limited to mature ruminants and horses with low nutrient requirements
• Limited nutrient yield, limits use for species and classes with higher nutrient requirements
• Basis is result of structural CHO, lignin, and CP
• Digestibilities of structural CHO and lignin are low
• Decreases rate of digestion, therefore decreases passage rate, therefore decreases consumption
• Low digestibilities also decrease total nutrients derived from roughage
• Table 7-39 on page 161 of text – Effect of roughage quality on consumption, digestibility, and rumen turnover rate
• Low CP quantity and quality
• Rumen microbes require N source to digest structural CHO
• Limiting N, reduces production of energy-yielding compounds from roughages
• In general, minimum CP content is 8%
• Ruminant does have short-term mechanisms to fulfill N requirements
• Supplementation
• Generally required to effectively use low-quality roughages
• Generally, protein, energy, minerals, and vitamins
• CP
• CP or N promotes microbial activity
• Consider content, solubility, and digestibility
• True protein preferred
• Processing and treatment
• Improves digestibility, passage rate, and consumption
• Increases digestibility and nutritional value
• Physical methods
• Pelleting, chopping, grinding, and pressurized steam
• Chemical methods
• Alkaline compounds
• Dissolve lignin
• Increase digestibility
• NaOH
• Applied to dry roughages or prior to ensiling
• Disadvantages
• Generally, not economical
• Increases sodium to animal
• Sodium contamination of soil
• Concentrated, hazardous chemical
• Ammonia
• Anhydrous ammonia
• Applied to stacked, covered roughages
• Reaction requires several weeks
• Rate of reaction related to ambient temperature and moisture content of roughage
• For maximum benefit, provision of energy supplement to animal
• Do not apply to high-quality roughages
• Compared to NaOH
• Less hazardous
• More economical
• Provides source of N
• Lower increase in digestibility
• Feeding animals
• Mature ruminants and horses
• Given ration formulated to fulfill nutrient requirements
• Added in lesser amounts
• High-concentrate rations
• Cost-effective source of structural CHO