ANSC 318 1st Edition Lecture 8 Outline of Last Lecture I. Feed Energy Types and Methods of Measuring Heat Increment Outline of Current Lecture II. Measuring Energy Loss in Feedstuffs and Feedsa. Measuring Heat Incrementb. Measuring Net Energyc. Calculating Heat Increment and Net Energy Valuesd. ComparingIII. Evaluation of Proteina. Nonruminants vs RuminantsIV. Methods to Assess Protein Quality in Nonruminantsa. Protein Efficiency Ratiob. Biological Valuec. Ideal Protein ConceptV. Protein Digestion and Metabolism in RuminantsVI. Metabolizable ProteinVII. Undegradable Intake ProteinCurrent LectureMeasuring Energy Loss in Feedstuffs and Feeds-there are 2 sources of heat  heat increment and heat from maintenanceTo Measure the HI of a Feedstuff:1. adapt animal to test diet2. adapt animal to calorimeter3. Measure HP at 2 levels of ME intake4. HI = change in Y / change in X (i.e. slope)-roughage has a higher HI than grain which means it also has a higher energy costMeasuring HI in a Feed:Level of Intake (kg/day) ME Intake (Mcal/day) Heat Production (Mcal/day)High Intake (12.5 kg/day) 25.0 17.0Low Intake (5.0 kg/day) 10.0 8.0These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Change in ME Intake (Mcal/day)15.0 - -Change in Heat Production (Mcal/day)- - 9.0 Measuring NE Value of Alfalfa Hay Fed to Steers:1. Measure GE using bomb calorimeter-GE = 4.5 Mcal/kg DM 2. Conduct digestion trial to measure FE and UE losses-FE = 2.0 Mcal/kg DM -UE = .1 Mcal/kg DM3. Measure CH4 (GDP) energy losses using calorimetry to measure total CH4 produce-GDP = 0.4 Mcal/kg DM4. Calculate DE (Mcal/kg DM) = 4.5 – 2.0 = 2.55. Calculate ME (Mcal/kg DM) = 4.5 – (2.0 + 0.1 + 0.4) = 2.0Calculating HI Values:-HI (%) = (9/15) * 100 = 60%-HI (Mcal/kg DM) = ME – HI% = 2.0 * (60/100) = 1.2-HI for alfalfa hay = 1.2 Mcal/kg DMComparing Energy Values:Energy Unit (DM Basis)Corn Grain Bermuda Grass Alfalfa HayGE, Mcal/kg 4.45 4.35 4.50DE, Mcal/kg 3.90 3.00 2.50ME, Mcal/kg 3.25 2.46 2.00NE for Growth, Mcal/kg1.55 0.97 0.80HI, % of ME 52.3 60.6 60.0-NE:DE ratio becomes smaller as quality decreasesEvaluation of ProteinNonruminants vs Ruminants:Nonruminants:-all essential AA’s must be in diet in correct amounts and proportionsRuminants:-evaluation of protein quality is much more complex-diet must provide nitrogen for microbial synthesis and sufficient quantities of essentialAA’s for absorption in the small intestine-need to be able to make good quality Metabolizable ProtienMethods to Assess Protein Quality in Nonruminants1. Protein Efficiency Ratio (PER)-Protein Efficiency Ratio (PER)  uses growth rate per unit of intake protein to measure protein quality-PER = weight gain (g) / protein consumed (g)-increased ratio = increased protein qualityProtein Source (Nonruminants) Protein Efficiency RatioCasein (milk protein) 2.50Egg Protein 3.18Soybean Meal 2.21Corn Grain (Cereal Grain) 0.49Casein + Corn Grain 2.68-cereal grain = deficient in a lot of essential AA’s (low concentration)-casein + corn grain = AA’s complement each other2. Biological Value:-direct measure of the proportion of feed protein that can be used by the animal for synthesis of body tissue (muscle, collagen, etc.)-indirect measure of the blend of essential AA’s in a feed-proportion of absorbed nitrogen that is retained by an animal-BV = nitrogen retained in body tissue / digestible nitrogen-BV = (N intake – fecal N – urine N) / (N intake – fecal N)-a higher concentration of nonessential AA’s causes a lower BV because more nitrogenis excreted in urineBV Values of Feeds for Pigs:Feed Biological ValueMilk protein 0.95 to 0.97Fish Meal 0.75 to 0.90Soybean Meal (gold standard plantbase) 0.65 to 0.75Cottonseed Meal 0.60 to 0.70Linseed Meal 0.60 to 0.70Corn Grain 0.50 to 0.60Barley Grain 0.50 to 0.603. Ideal Protein Concept:-ideal protein is patterned after the composition of protein in lean muscle tissue-provides the essential AA’s in the correct proportion so that tissue growth is maximized-species specificRecommended Essential AA profile in pigs:-Arginine = 3.0%-Histidine = 1.8%-Isoleucine= 3.8%-Leucine = 5.0%-Lysine = 7.0%-Methionine + Cystine = 3.4%-Phenolalanine + Tyrosine = 5.5%-Threonine = 4.0%-Tryptophan = 1.0%-Valine = 4.0%-Lysine is typically the most limiting AA -the rate limiting essential AA (EAA) is the most deficient in matching the ideal protein profile-other than lysine; methionine, threonine, and tryptophan are common rate limiting EAAsProtein Digestion and Metabolism in Ruminants1. Rumen microbes provide a large portion of the animal’s energy requirements by transforming dietary CHOs to VFAs2. microbes need to be supplied the nutrients to grow and multiply3. involves large-scale microbial synthesis4. rumen microbes (bacteria, protozoa, and fungi) contain 30-50% CP (DM basis)-concentration of AAs differ greatly between ruminants and nonruminants-to get true protein into the small intestine for AA absorption, it must be Undegradable Intake Protein (UIP), otherwise rumen microbes will convert them to VFAs 5. microbial protein is rich in EAA6. BV of microbial protein is 0.6 to 0.8 (similar to soybean meal) ***7. efficiency of microbial growth depends on availability of N and timing of availability of carbon skeletons8. fraction of feed protein escapes rumen degradation and goes to small intestine with microbialprotein to be digested9. this is UIP or bypass proteinMetabolizable Protein-protein available for the animal to absorb in the small intestine-2 sources of metabolizable protein  UIP and microbial proteinUIP Values:-Low = 20-30% (hay, corn silage, barley grain, soybean meal)-Medium = 40-60% (cottonseed meal, corn grain, alfalfa meal)-High = 65-80% (blood meal, feather meal, fish meal)-when UIP increases, so does production potential-increased protein = increased milk-increased lysine in UIP = increased milk