About myself…

1. About myself… • 3rd year Graduate Student at UBC • working towards a Master of Science Degree • Program: Ruminant nutrition • Department: Animal Science • Faculty: Agricultural Sciences

2. Where I work… -UBC Dairy Education and Research Centre -Pacific Agri-Food Research Centre (PARC) Agassiz, BC

3. The main dairy barn 225 lactating cows 200 cow replacement herd

4. In the dairy barn Free stall design 12 cow groups Parallel double 12 milking parlour

5. My Research: • Study the effects of nitrogen (N) fertilization on protein quality of forage grass

6. Nitrogen forms • N2: nitrogen gas • NO3-: nitrate • NO2-: nitrite • NH3: ammonia

7. Amino Acid H H O N-C-C An amino acid H R OH

8. Proteins • 2 amino acids together: dipeptide • 3 or more amino acids together: polypeptide • Polypeptide chain(s): protein

9. Plant nitrogen • 80% of the atmosphere composed of N2 • This N is unavailable for plant nutrition • Ammonia (NH3 ) is the only form of nitrogen that can be utilized by the plant

10. Nitrogen fixation and oxidation • Nitrogen fixation: convert N2 to NH3 • Rhizobium and other types of bacteria have enzymes that fix nitrogen • Nitrogen oxidation: convert N2 to NO3- • Lightning oxidizes nitrogen

11. Nitrate converted to ammonia • Plants and bacteria have enzymes that are capable of converting NO3- to NO2 - • Plants and bacteria also have enzymes that are capable of convertingNO2 – to NH3

12. Ammonia to amino acids, etc. • Ammonia is converted via metabolic pathways into amino acids, nucleotides, and other nitrogen containing molecules.

13. The nitrogen cycle N2 NO3- NO2 - NH3 amino acids, nucleotides, etc.

14. Nitrogen fertilizers • Ammonia, nitrates • Urea, urea formaldehyde • Urease required for breakdown • Organic wastes • Slow release

15. Cows are ruminants rumen reticulum omasum abomasum

16. Ruminants • “Four chambered stomach”: • Reticulum sorts feed • Rumen is full of microbes that ferment feed • Largest compartment (fits up to 200lbs of feed) • Omasum filters and absorbs • Abomasum is comparable to our stomach • Cows ruminate

17. Cows are ruminants rumen reticulum omasum abomasum

18. Nutrition Made Simple • Cows (like us) are a moving clump of matter • Cows need both building material and energy (to build and move) in diet • Building material comes from protein • Energy comes from carbohydrates

19. Ruminant nutrition protein terms… • Crude protein: % nitrogen in a sample x 6.25 • “Typical” protein molecule is 1/16 nitrogen • 1/16 = 0.0625 • Problem: not all nitrogen in food is in protein form

20. Non Protein Nitrogen and True Protein: • Crude protein is made up of non-protein nitrogen (NPN) and true protein (TP) • Non-protein nitrogen (NPN): nitrogen not in protein molecules (free peptides, free aa, nitrates, ammonia, etc) • True protein (TP): nitrogen in the form of proteins (peptides linked together)

21. Protein: • Rumen degradable protein (RDP): non-protein nitrogen (NPN) and true protein (TP) that is degraded into non-protein nitrogen in the rumen. • Rumen undegradable protein (RUP): true protein (TP) that is not degraded in the rumen.

22. Protein in Feed NPN RDP TP crude protein RUP

23. Protein Digestion Rumen Feed RDP rumen degradable protein Crude Protein ammonia Microbial protein built using N from RDP RUP rumen undegraded proteins Intestine Digestion of MP and RUP

24. Carbohydrate digestion Feed Rumen Carbs Sugar Used by microbes for energy Fermentation VFAs Waste product of microbes Energy Source for Cow

25. Energy metabolism in humans cell glucose Pyruvic acid Acetyl CoA ADP O2 Citric acid cycle CO2 mitochondria nucleus ATP H2O

26. The three VFAs used for energy: • Acetate • Butyrate • Propionate

27. VFA metabolism in cows Butyrate cell Acetate Ketone bodies Propionate Acetyl CoA ADP O2 Citric acid cycle CO2 mitochondria nucleus ATP H2O

28. Humans: Excess glucose used to make fat Cattle: Unable to make fat directly from glucose Excess acetate used for fat production Human vs. Cattle fat production

29. My Research: RUP from Forage Grass Problems: • Lactating dairy cows need a lot of protein in their diet • A lot of dairy cow diets have too much RDP and too little RUP

30. Environmental concerns • Both NO3- and NH4+ are water soluble • NO3- is also readily leached out of the soil • NH4+ associates with soil colloid particles and resists leaching

31. Plant Nitrogen usage nitrates, ammonia etc. converted into plant proteins nitrates, ammonia etc. taken up by plants nitrates, ammonia etc. from ground

32. Possible Solution Increase the RUP content of forages: • Reduce N fertilization • Alter harvest schedules • Identify genetics that give more RUP

33. What we are doing • We are growing three types of grass in 56 plots • Each plot is either given 0, 200, or 400 kgs of N fertilizer a year • Plots are cut several times a year and grass is allowed to dry to between 25-35% DM

34. plots of grass

35. The Haldrup Logster Harvester

36. Harvesting the plots

37. Harvest • Grass is chopped and put into mini silos • Samples are taken before and after ensiling and analyzed for CP, TP and fibre

38. hydraulic press mini silo

39. Drying oven

40. Rumen Degradabilities • Silage is incubated in the rumens of cannulated cows: • Incubated silage analyzed for CP • Know N percentage before and after • Assess RDP and RUP

41. A rumen cannulated cow cannula plug

42. The cannulated cow barn

43. Feeding the cows is a good way to distract them

44. Taking the plug out of the cannula

45. feed being digested

46. Cannula Rumen wall Mesh bag

47. Sample bags

48. Up to my armpit in a cow's rumen

49. What We Have Found: • Reducing N fertilizer levels decreases the content of non-protein nitrogen (NPN) in grass • Less non-protein nitrogen = more true protein in grass • More true protein = more rumen undegradable protein

50. Consider a Career in Agricultural Science • Agricultural community/ farm background • Education in rural setting • Good job prospects