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

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

225 lactating cows 200 cow replacement herd

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

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

Nitrogen forms N 2 : nitrogen gas N 2 : nitrogen gas NO 3 - : nitrate NO 3 - : nitrate NO 2 - : nitrite NO 2 - : nitrite NH 3 : ammonia NH 3 : ammonia

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

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

Plant nitrogen 80% of the atmosphere composed of N 2 80% of the atmosphere composed of N 2 This N is unavailable for plant nutrition This N is unavailable for plant nutrition Ammonia (NH 3 ) is the only form of nitrogen that can be utilized by the plant Ammonia (NH 3 ) is the only form of nitrogen that can be utilized by the plant

Nitrogen fixation and oxidation Nitrogen fixation: convert N 2 to NH 3 Nitrogen fixation: convert N 2 to NH 3  Rhizobium and other types of bacteria have enzymes that fix nitrogen Nitrogen oxidation: convert N 2 to NO 3 - Nitrogen oxidation: convert N 2 to NO 3 -  Lightning oxidizes nitrogen

Nitrate converted to ammonia Plants and bacteria have enzymes that are capable of converting NO 3 - to NO 2 - Plants and bacteria have enzymes that are capable of converting NO 3 - to NO 2 - Plants and bacteria also have enzymes that are capable of converting NO 2 – to NH 3 Plants and bacteria also have enzymes that are capable of converting NO 2 – to NH 3

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

The nitrogen cycle N2N2N2N2 NO 3 - NO 2 - NH 3 amino acids, nucleotides, etc.

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

Cows are ruminants abomasum rumen omasum reticulum

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

Cows are ruminants abomasum rumen omasum reticulum

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

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

Non Protein Nitrogen and True Protein: Crude protein is made up of non-protein nitrogen (NPN) and true protein (TP) 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) 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) True protein (TP): nitrogen in the form of proteins (peptides linked together)

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

Protein in Feed

Protein Digestion ammonia

Carbohydrate digestion

Energy metabolism in humans nucleus mitochondria cell glucosePyruvic acid Acetyl CoA Citric acid cycle O2O2 CO 2 ATP H2OH2O ADP

The three VFAs used for energy: Acetate Butyrate Propionate

VFA metabolism in cows nucleus mitochondria cell Butyrate Ketone bodies Acetyl CoA Citric acid cycle O2O2 CO 2 ATP H2OH2O ADP Acetate Propionate

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

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

Environmental concerns Both NO 3 - and NH 4 + are water soluble Both NO 3 - and NH 4 + are water soluble NO 3 - is also readily leached out of the soil NO 3 - is also readily leached out of the soil NH 4 + associates with soil colloid particles and resists leaching NH 4 + associates with soil colloid particles and resists leaching

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

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

What we are doing We are growing three types of grass in 56 plots 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 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 Plots are cut several times a year and grass is allowed to dry to between 25-35% DM

The Haldrup Logster Harvester

Harvesting the plots

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

Drying oven

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

The cannulated cow barn

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

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