1. Environmental Nutrition to Reduce Nutrient Excretion and Air Emissions

2. 10-2 Nutrient excretion Nutrients excreted = Nutrient ingested - Nutrients digested Therefore, excretions represent an inefficiency

3. 10-3 Nutrient excretion dependent on: Quantity of endogenous losses (function of maintenance) Amount of dietary nutrient consumed relative to nutrient needs (excesses) Efficiency of nutrient utilization and retention Interrelationships of nutrients

4. 10-4 Precision nutrition Meeting nutrient needs while minimizing nutrient excesses

5. 10-5 Challenges to precision feeding Determining nutrient needs –Stage of growth –Genetic-specific –Management-dependent Estimation of nutrient digestibility/bioavailability Variation in feed ingredient composition

6. 10-6 Nutrients available for growth Feed provided Feed waste Intestinal secretions (enzymes, cells) Nutrients absorbed Feed consumed Nutrients used for growth Inefficiencies Growth Mismatch Waste The key: understanding inefficiencies in nutrient utilization Many steps are involved in the utilization of nutrients. –Each step has inefficiencies associated with it. The key to reducing waste is to understand where utilization can be influenced. Maintenance Undigested feed and secretions

7. 10-7 Feed Waste: an expensive waste of nutrients Feed waste: –Adherence: pigs take 1.5 g feed away from feeder 60 times per day (~ 4% of “intake”)  Portion may be returned –Spillage: pigs push feed out of feeder (in practice, range 1.5% to 20%) Feed provided Feed waste Waste -Rooting: Dairy cows pick through their feed; refusing as much as 10% of what is offered

8. 10-8 Feeder management Traditional guidelines: –Proper feeder care and adjustment can reduce feed waste drastically  Bottom of feeder should be 50% covered with FRESH feed  Pig needs to exert effort to eat  Feeders should be inspected at least weekly  Clean and adjust where necessary

9. 10-9 Present feed in most palatable form Feed should be pelleted –Reduces feed waste ~5% Dry feed is not very palatable –Pigs move back and forth from feeder to waterer while eating  Augments feed waste

10. 10-10 Present feed in most palatable form (continued) Wet-dry or liquid feeders –Back and forth motion is prevented  Reduces feed waste  Increases feed intake  Increases gain

11. 10-11 Enzymes required for digestive process contribute to waste through catabolism Upon consumption, the animal excretes proteins and enzymes, e.g., during chewing –Equals to ~30% of protein intake Feed provided Feed waste Waste Intestinal secretions (enzymes, cells) Feed consumed Inefficiencies

12. 10-12 Enzymes required for digestive process contribute to waste through catabolism (continued) –During synthesis, inefficiencies occur  Protein is catabolized  N is excreted (mainly in urine) As much as 10% of dietary N may be excreted

13. Enzymes required for digestive process contribute to waste and not all are reabsorbed Approximately 25% of the enzymes secreted are not reabsorbed in the small intestines –Are fermented in large intestines  Contribute to odor –Remains are excreted  Contribute to waste Feed provided Feed waste Waste Intestinal secretions (enzymes, cells) Inefficiencies Undigested feed and secretions

14. 10-14 Feed quality affects enzyme production and thus catabolism Factors augmenting enzyme secretions: –Anti-nutritional factors such as trypsin inhibitor  Found in (underprocessed) soybean meal –Protein content of the diet –Overprocessed ingredients?

15. 10-15 Enzymes open opportunities Fiber-degrading enzymes –Wheat/barley/rye as major ingredients:  Xylanase/beta-glucanase improve digestibility 2% to 9% –Corn-soy diets:  Alpha-galactosidase, proteases, etc. may prove effective

16. 10-16 Phytase has a major effect on P availability Plants contain a large portion of P in the form of phytate –Pigs cannot digest phytate  Most plant phosphorus is thus unavailable Phytase can break down phytate, releasing the P –The availability of P increases from 30% to 50% in typical diet  30% reduction in P excretion

17. 10-17 Phytase to reduce P excretion Some research has demonstrated added performance with phytase Potential to increase critical amino acid digestibility May increase zinc and other trace mineral absorption Diet costs are typically not increased

18. 10-18 Nutrient Digestibility Available nutrients = absorbed - “expenses ” Ileal digestible nutrients –Estimate of availability Available nutrients are destined for: –Maintenance –Growth Feed provided Feed waste Waste Undigested feed and secretions Intestinal secretions (enzymes, cells) Nutrients absorbed Feed consumed Inefficiencies

19. 10-19 Nutrient Digestibility For a typical diet, 8% of protein and 70% of phosphorus is not digested –Indigestible proteins are fermented in large intestines  Contributes to odor –Remains are excreted  Contributes to waste Feed provided Feed waste Waste Intestinal secretions (enzymes, cells) Inefficiencies Undigested feed and secretions

20. 10-20 Reduce the indigestible fraction by selecting highly digestible ingredients

21. 10-21

22. 10-22 New crops offer solutions as well De-germed, de-hulled corn

23. 10-23 Processing can improve nutrient digestibility Grinding: –Grind feed to uniform particle size of ~ 600 microns. Pelleting: –Improves protein digestibility 3.7%. Expanding/extruding: –Improves pellet quality. –Effects on digestibility very diet-dependent.  Effects can be negative! Flaking/rolling/cracking: –Improves digestibility by >10%

24. 10-24 Mineral bioavailability 30% improvement in bioavailability of organic mineral sources (chelates) compared to inorganic sources (Leeson et al., 2003)

25. 10-25

26. 10-26 Maintenance, although essential, results in waste Feed provided Feed waste Intestinal secretions (enzymes, cells) Nutrients absorbed Feed consumed Inefficiencies Waste Undigested feed and secretions Maintenance Maintenance is obligatory –Basic function of life Nutrients used for “maintenance” are ultimately catabolized (broken down) –Maintenance requirement depends on size of animal

27. 10-27 Maintenance, although essential, results in waste (continued) –Five-lb pig:  Lysine: 2.6% of requirement  Threonine: 6.1% of requirement –250-lb pig:  Lysine: 8.8% of requirement  Threonine: 19.4% of requirement

28. 10-28 Maintenance-linked waste cannot be reduced By improving daily lean gain, maintenance waste becomes relatively less important –Optimize production  Optimize management  Optimize animal health  Optimize nutrition, etc.

29. Absorbed nutrients can be used for maintenance, followed by growth, presuming the profile matches Feed provided Intestinal secretions (enzymes, cells) Nutrients available for growth Feed consumed Nutrients absorbed Undigested feed and secretions Feed waste Inefficiencies Mismatch Waste Maintenance Nutrients are required in specific ratio for growth –The most limiting nutrients sets the upper limit for growth –Excesses for other nutrients are catabolized and/or excreted For a typical diet, –30%-35% is “mismatched”

30. 10-30 Ideal protein concept

31. 10-31

32. 10-32 All excess protein above requirements have no value Excess protein is absorbed at the small intestine – Protein is deaminated in the liver – Urea is subsequently excreted in urine at the kidney Protein requirements Theory for lowering protein

33. 10-33 Urea is rapidly converted to ammonia following deposition Therefore, – feeding less protein leads to less urea excretion – reduced urea excretion should decrease ammonia Protein requirements (Continued) A 1% point reduction in dietary protein results in a 10% decrease in N excretion and ammonia emission

34. 10-34

35. The more ingredients used, the better the match! Major portion of nutrients in feed is wasted because diet is not ideal Contributors to this problem: –Small number of ingredients  Limits flexibility in matching animal-specific profile

36. 10-36 +3.50-1.400Change diet costs, $/ton 4122---Reduction N excreted, % 243241N excreted, total, g/d 172534N excreted urine, g/d 26 N retained, g/d 777N excreted feces, g/d 435160N absorbed, g/d 505867N intake, g/d 10% CP + lysine +threonine + typtophan 12% CP + lysine 14% CPDiet Concentration N Balance Theoretical Reduced N Excretion

37. 10-37 Diets should be optimally matched to the animal’s requirement Nutritional requirements change with: –Maintenance requirement (affected by sex, age, and weight). –Gain and composition of gain. –Product yield and composition. –Health status, environmental conditions, and activity.

38. 10-38 – Temperature outside of thermo-neutral zone.  Energy used for thermo-regulation.  Increase energy-to-protein ratio. Diets should be optimally matched to the animal’s requirement (continued)

39. Phase feeding reduces waste Nutritional requirements change continuously –Protein to energy ratio of feed decreases with age  Diet should be adjusted to match this decrease  Phase feeding

40. 10-40 Examples of nutritional strategies –Grouping for production, stage of growth, or weight range –Split-sex feeding  Barrows require more energy for maintenance than gilts  Increase energy to protein ratio of the feed for barrows Diets should be optimally matched to the animal’s requirement (continued)

41. 10-41 Inefficiencies occur when the diet provides more nutrients than the animal needs: More phases/groups = less waste

42. 10-42 Phase-feeding diets are also cheaper, but the extra hassle may outweigh the benefits More phases/groups = less waste and cheaper diets –But also = more hassle –Compromise between number of phases/groups and benefits achievable In-line mixers/liquid feeding systems allow for continuously changing the diet composition without increasing hassle

43. 10-43 Precision nutrition is further hindered by feed manufacturing problems Feed manufacturing problems –Variation in ingredient quality  Somewhat compensated for by over formulating (= more waste) –Weighing errors –Mixing problems

44. 10-44 Inefficiencies are linked to tissue accretion Inefficiencies occur in the production of tissues –A portion of the nutrients is broken down –Remnants are excreted  N Mainly in urine Responsible for excretion of 10% of dietary N Feed provided Feed waste Undigested feed and secretions Intestinal secretions (enzymes, cells) Nutrients absorbed Maintenance Nutrients available for growth Feed consumed Nutrients used for growth Inefficiencies Growth Mismatch Waste

45. 10-45 Improving the efficiency of tissue accretion requires pharmacological interventions Difficult to improve through nutritional means Compounds such as the beta-agonists (Ractopamine), improve the efficiency of nutrient utilization –Offer great potential for reducing nutrient waste

46. 10-46 Potential reduction Examples

47. 10-47 P Intake, Retention and Excretion 12.2 g 26 g 13.8 g 12.2g 6.38 lb bird 1.93 feed to gain 49 days of age RA0109 exp results 36.2g P 17.1g P Agristats, 1999 (control) Industry+Phy 30.8g P 13.8 g P 19.3 % 17.0g P

48. 10-48 P Intake, Retention and Excretion 12.2 g 26 g 13.8 g 12.2g 6.38 lb bird 1.93 feed to gain 49 days of age RA0109 exp results 36.2g P 17.1g P Agristats, 1999 (control) UMD Rcmd 31.7g P 14.8 g P 22.5 % 16.9g P

49. 10-49 P Intake, Retention and Excretion 12.2 g 26 g 13.8 g 12.2g 6.38 lb bird 1.93 feed to gain 49 days of age RA0109 exp results 36.2g P 17.1g P Agristats, 1999 (control) UMD Rcmd+Phy 28.8g P 11.9 g P 30.5 % 16.9g P

50. 10-50 P Intake, Retention and Excretion 12.2 g 26 g 13.8 g 12.2g 6.38 lb bird 1.93 feed to gain 49 days of age RA0109 exp results 36.2g P 17.1g P Agristats, 1999 (control) UMD Rcmd+Phy+25OHD3 26.8g P 10.0 g P 41.5 % 16.8g P

51. 10-51

52. 10-52 P<0.0001 -33% -22% -48% Powers et al., 2004 (unpublished)

53. Where does all of the waste end up? Feces contain the remnants of the digestive process – Undigested feed – Endogenous losses  Odor – But also excess zinc and copper  Excreted through bile and excreted as feces – Uptake of calcium and phosphorus is regulated  Excess is excreted as feces Feed waste Inefficiencies * enzyme prod. * tissue accretion Mismatch Undigested feed and secretions Maintenance } Feces Urine Manure pit

54. 10-54 Urine contains the remnants of metabolism –Urea from protein breakdown  Some diverted to feces –Excess potassium, sodium, and chlorine Where does all of the waste end up? (continued)

55. 10-55 Odor compounds: fermentation products of remnants of the digestive process Undigested feed + endogenous losses –Subject to fermentation in the large intestines  Fiber and carbohydrates:  Volatile fatty acids (e.g., butyric acid)

56. 10-56 Odor compounds: fermentation products of remnants of digestive process (continued)  Proteins:  Volatile fatty acids  Phenolics (para-cresol, skatole)  Mercaptans (hydrogen sulfide, methyl mercaptan)  Amines (putrescine, cadaverine)  Sulfur:  Mercaptans

57. 10-57 Diets can be formulated to yield less odor Odor emission is difficult to study –Data on effects of feed digestibility on odor are circumstantial  But theoretically effect should be strong Low-protein diets proven to reduce odor Low-sulfur diet proven to reduce odor

58. 10-58 Sulfur converts to mercaptans Methionine, cysteine, and taurine are sulfur-containing “amino acids” –Upon catabolism, they can contribute to sulfur odor. Many minerals are fed as sulfur salts –High bio-availability with relatively low cost  Impact on odor has been ignored

59. Urea in urine: major source of ammonia Urea, the form in which nitrogen is excreted, is not stable –Urease (of bacterial origin) converts urea to ammonia  Ammonia is volatilized from urine/manure based on  Surface area  Temperature  Air flow across manure surface  pH  Ammonia concentration