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UBC Dairy Education and Research Centre

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					About myself…
 3rd year Graduate Student at UBC
 working towards a Master of Science
  Degree
 Program: Ruminant nutrition
 Department: Animal Science
 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
Cows are ruminants


   rumen


              omasum
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
Cows are ruminants


   rumen


              omasum
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
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
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)
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.
Protein in Feed
Protein Digestion


         ammonia
Carbohydrate digestion
 Energy metabolism in humans

                                                 cell

glucose    Pyruvic acid

O2         Acetyl CoA       ADP

                             Citric acid cycle
CO2
                          mitochondria
                 ATP                             nucleus
     H2O
The three VFAs used for energy:

 Acetate
 Butyrate
 Propionate
      VFA metabolism in cows
      Butyrate
                                                     cell

     Acetate     Ketone bodies
Propionate       Acetyl CoA      ADP
     O2
                                 Citric acid cycle
     CO2
                              mitochondria
                       ATP                           nucleus
        H2O
Human vs. Cattle fat production
   Humans:                   Cattle:

       Excess glucose          Unable to make fat
        used 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

   A lot of dairy cow diets have too much RDP
    and too little RUP
Plant Nitrogen usage



                     nitrates, ammonia etc. converted into plant
                     proteins



                     nitrates, ammonia etc. taken up by
                     plants




nitrates, ammonia etc. from ground
Possible Solution
Increase the RUP content of forages:

 Reduce N fertilization
 Alter harvest schedules
 Identify genetics that give more RUP
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
The Haldrup Logster Harvester
Harvesting the plots
Harvest
   Grass is chopped and put into mini silos

   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:
 Incubated silage analyzed for CP
 Know N percentage before and after
 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

   Less non-protein nitrogen = more true protein in
    grass

   More true protein = more rumen undegradable
    protein
Consider a Career in
Agricultural Science

   Agricultural community/ farm background

   Education in rural setting

   Good job prospects

				
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posted:11/10/2011
language:English
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