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 Feeds a Measuring Heat Increment b Measuring Net Energy c Calculating Heat Increment and Net Energy Values d Comparing III Evaluation of Protein a Nonruminants vs Ruminants IV Methods to Assess Protein Quality in Nonruminants a Protein Efficiency Ratio b Biological Value c Ideal Protein Concept V Protein Digestion and Metabolism in Ruminants VI Metabolizable Protein VII Undegradable Intake Protein Current Lecture Measuring Energy Loss in Feedstuffs and Feeds there are 2 sources of heat heat increment and heat from maintenance To Measure the HI of a Feedstuff 1 adapt animal to test diet 2 adapt animal to calorimeter 3 Measure HP at 2 levels of ME intake 4 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 cost Measuring HI in a Feed Level of Intake kg day High Intake 12 5 kg day Low Intake 5 0 kg day ME Intake Mcal day 25 0 10 0 Heat Production Mcal day 17 0 8 0 These 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 Change in Heat Production Mcal day 15 0 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 DM 3 Measure CH4 GDP energy losses using calorimetry to measure total CH4 produce GDP 0 4 Mcal kg DM 4 Calculate DE Mcal kg DM 4 5 2 0 2 5 5 Calculate ME Mcal kg DM 4 5 2 0 0 1 0 4 2 0 Calculating 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 DM Comparing Energy Values Energy Unit DM Corn Grain Bermuda Grass Alfalfa Hay Basis GE Mcal kg 4 45 4 35 4 50 DE Mcal kg 3 90 3 00 2 50 ME Mcal kg 3 25 2 46 2 00 NE for Growth 1 55 0 97 0 80 Mcal kg HI of ME 52 3 60 6 60 0 NE DE ratio becomes smaller as quality decreases Evaluation of Protein Nonruminants vs Ruminants Nonruminants all essential AA s must be in diet in correct amounts and proportions Ruminants evaluation of protein quality is much more complex diet must provide nitrogen for microbial synthesis and sufficient quantities of essential AA s for absorption in the small intestine need to be able to make good quality Metabolizable Protien Methods to Assess Protein Quality in Nonruminants 1 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 quality Protein Source Nonruminants Protein Efficiency Ratio Casein milk protein 2 50 Egg Protein 3 18 Soybean Meal 2 21 Corn Grain Cereal Grain 0 49 Casein Corn Grain 2 68 cereal grain deficient in a lot of essential AA s low concentration casein corn grain AA s complement each other 2 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 nitrogen is excreted in urine BV Values of Feeds for Pigs Feed Biological Value Milk protein 0 95 to 0 97 Fish Meal 0 75 to 0 90 Soybean Meal gold standard plantbase 0 65 to 0 75 Cottonseed Meal 0 60 to 0 70 Linseed Meal 0 60 to 0 70 Corn Grain 0 50 to 0 60 Barley Grain 0 50 to 0 60 3 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 specific Recommended 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 EAAs Protein Digestion and Metabolism in Ruminants 1 Rumen microbes provide a large portion of the animal s energy requirements by transforming dietary CHOs to VFAs 2 microbes need to be supplied the nutrients to grow and multiply 3 involves large scale microbial synthesis 4 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 EAA 6 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 skeletons 8 fraction of feed protein escapes rumen degradation and goes to small intestine with microbial protein to be digested 9 this is UIP or bypass protein Metabolizable Protein protein available for the animal to absorb in the small intestine 2 sources of metabolizable protein UIP and microbial protein UIP 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 productions