Week 3

Protein Sources

Nonprotein Nitrogen (NPN) Compounds

Text Transcript

Follow along with the audio...

• Introduction
• Nitrogen in form other than peptides or proteins
• Classified
• Organic compound
  • Urea, amides, amines, amino acids, and peptides
• Figure 7.7 – Chemical structure of urea

• Inorganic compounds
• Inorganic salts such as ammonium chloride, phosphate, and sulfate
• Feeding
• NPN fed exclusively to mature ruminants
• NPN not fed to poultry, swine, or horses
• Exception: amino acids fed to all species
• Metabolism of NPN compounds
• Rumen microorganisms
• Metabolize NPN compounds to ammonia
• Combine ammonia with carbon chains to form amino acids
• Incorporate amino acids into microbial protein
• Microbial protein
• Digested in abomasum and small intestine
• Absorbed in small intestine
• Metabolized in ruminant tissues
• Factors influencing metabolism efficiency
• Type and number of microorganisms
• Presence of substrates
• Nitrogen source – ammonia
• Energy source - readily available carbohydrates
• Minerals
• Vitamins
• Synchronization of amount and availability
• Urea
• Introduction
• Primary NPN compound
• Figure 7.8 – Feed urea



• CP 281%
• Discussion will focus on urea; may also apply to other NPN compounds
• Optimize use of urea
• Feed only to ruminants
• Supply adequate carbohydrates
• Energy and carbon skeleton
• Provide balanced diet
• Mix feed well
• Do not feed excessive levels
• Limit to 1/3 of total protein in ration
• Feed additional protein sources to young and high producing animals
• Feed small amounts frequently
• Provide transition period
• Provide adequate water
• Methods of delivery
• Mixed in concentrate feeds
• Added to liquid supplement
• Added to salt block
• Combined with silage
• Added to dry roughages
• Slow-release product
• Maximize CP synthesis
• Reduce opportunity for toxicity
• Factors influencing method of delivery
• Protein requirements of animal
• Availability of urea
• Opportunity for toxicity
• Cost
• Availability of energy
• Other protein sources in ration
• Urea toxicity
• Technically, ammonia toxicity
• Typically, over-consumption in short period of time
• Etiology
• Ammonia in rumen exceeds amount able to be metabolized by microbes
• Excess ammonia absorbed
• Ammonia at liver exceeds liver’s capacity to convert ammonia to urea
• Excess ammonia enters blood stream
• Toxic to animal
• Signs
• Apparent as soon as 30 minutes post-consumption
• Include nervousness, staggering, also kicking at flank
• May also include labored breathing, incoordination, tetany, slobbering, and bloating
• Treatment
• Early stages
• Acidification of rumen
• Reducing pH, reduces absorption of ammonia
• Outcomes
• Death or survival with few effects
• Fatal dose
• Factors influencing amount of fatal dose
• Animal adapted to urea
• Consumption of other feeds
• Type of diet animal adapted to
• 40-50 g/100 kg of BW in 30 minutes
• Prevention
• Feeding management
• Methods to improve urea utilization
• NPN as silage additives
• Increases CP of forage
• Cost-effective
• More information in Module IX
• Extruded grain-urea mixtures
• Starea and GoldenPro
• Energy and slow-release NPN
• Various others on page 106 of text
• Note: data indicate rate of release not primary factor influencing utilization
• Biuret
• Figure 7.9 – Chemical structure of biuret



• Compared to urea
• More expensive
• Less available
• Less soluble
• More favorable response with low-quality forages
• More palatable
• Cannot be fed to lactating dairy cattle
• Ammoniated feeds
• Organic and inorganic salts used to effectively increase nitrogen content of feeds
• Feeds include molasses, beet and citrus pulp, cottonseed meal, rice products, and forages
• Ammoniated liquid feeds
• Ammonium lignin sulfonate
• CP 15-25%
• Fermented ammoniated condensed whey
• 69% CP (DM basis)
• Individual amino acid-based products
• Methionine hydroxyl analog, protected methionine, and protected lysine
• Source of respective amino acids
• Fed to monogastrics and high producing ruminants