Dairy Nutrition

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Dairy Nutrition

• David Marcinkowski
• AVS346
• Dairy Cattle Technology

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Dairy Nutrition

• Most important aspect of dairy management
• Affects
• Production
• Economics
• Health
• Reproduction
• Growth
• Crops
• Labor
• Genetic expression (limit).

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Feed Costs

• Feed Costs represent 40 - 60 of total costs on a
  dairy farm
• Witter Center feed costs averages
• 1100 - 1200 per cow per year
• 3.40 - 3.75 per lactating cow per day
• About 45,000 per year for the herd

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More Production With Less Costs

• Law of diminishing returns.
• Each additional unit of feed yields less milk.
• Pushing limits of management.
• More lactational stress.
• Higher production reduces marginal costs.
• Dilution of maintenance requirement.
• Maintenance stays the same regardless of milk
  production.
• Maintenance as a percent of the total becomes
  less.
• More profit.

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Nutrition Impacts Farms Nutrient Cycles

• C, N, P, K
• The major source of NPK coming onto the farm,
  comes in on the feed truck not the fertilizer
  truck. 
• Because dairy producers in Maine buy a lot of
  grain from other sources, nutrients tend to build
  up in the soil over time. It takes 2 - 5 acres of
  land just to get rid of the nutrients from one
  cow.
• Maine dairies require 2.5 3 acres per cow for
  forage production

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Nutritional Requirements
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Questions to Consider

• What are the goals of my herd?
• Purebred herd - shoot for high production and
  components
• Commercial herd - shoot for high income over feed
  costs 
• What feeds is my farm capable of producing?
• Soils and climate can limit the crop
  possibilities 
• What feeds are available to me off farm?
• Feedstuffs purchased locally
• What are my storage options?
• Facilities and herd size

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Eating Behavior

• Herd animals
• Advantage to eating quickly and chewing later to
  avoid predators
• Eat quickly
• Cows not too choosey, eat nails, wire, twine,
  etc.
• Cows eat often
• About 11 meals per day about 4-5 lbs. of DM per
  meal
• Drink 10 times per day about 1.5 gals. per drink
• Make feed readily accessible
• The harder it is for them to eat and drink the
  less they will eat and the less milk they will
  produce!

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Rumen Microbes

• Bacteria, protozoa fungi
• They provide 40 to 100 of a dairy cow's energy
  and protein requirements
• Cow provides them with Energy, Protein, Temp. pH
• Changes in diet need to be made slow
• Over 2 week period if possible
• First goal - Keep them happy!
• What do they eat?

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Rumen Microbes
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Rumen Bacteria

• 10 - 100 billion per ml
• Populations dependent on
• Diet, pH, turnover rate
• We always want to encourage cellulolytic
  bacteria. This enables us to feed cows cheap
• Manufacture
• Water soluble vitamins, VFA's, microbial proteins
  
• 25 in liquid phase
• 70 in solid phase
• 5 attached to rumen wall

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Rumen Protozoa

• 100,000 to 1 million/ml
• 2 of microbes
• 40 of the microbial mass
• Ingest bacteria
• Many prefer higher quality substrates - sugars
  and starches
• Stabilizing factor in the rumen
• pH sensitive