3 – Feeding Dairy Cattle Flashcards
Feeding costs
- Single HIGHEST production cost
o AB study: 30-35% total production costs
What are the components of a dairy cow diet?
- Fiber sources: milk fat production (acetate)
o Ex. alfalfa silage, pea silage, grass silage - Grains: gluconeogenesis (propionate)
o Ex. barley, corn - *some feed provide both grain and fiber
o Ex. corn silage, barley silage
Alfalfa
- *leaves
o Margin less than ½ serrate
Pea silage
- Can be difficult to grow alfalfa in some areas
- *tend to see higher milk fat, but lower milk protein (balance each other out in the end)
Barley
- Feed more in Canada compared to the states
o Grown better here due to temperature
o requires less heat and water compared to corn
Making a balanced ration
- determine content of available feedstuffs
o near infrared (NIR) + wet chemistry - determine animal requirements
DMI vs. milk production rules of thumb
- *DMI=critical for milk production
o Diet is usually 50% DM - 6kg ‘tax’ (4.5kg for jerseys)
- Multiple the remaining intake by 2=milk yield
If Holstein eating 25kg/day what would the milk yield be?
- Take away 6kg ‘tax’=19kg for milk production
- *38kg/day
What ‘drives’ DMI?
- Bodyweight
- Milk production (producing more=need more DMI)
- Body condition
- Implants
What limits DMI?
- Ration NDF: fiber
o Too much fiber=sits longer - Ration net energy
o Will get full before having enough to produce milk - Forage mass/allowance
- Ration protein (CP/TDN)
What are the environmental factors that change DMI?
- Air temperature
- Plant toxins
- Water requirement and intake
What is the 3 diets concept?
- Formulated
- Delivered
o Loading the mixer: first input of error - Consumed
o Can’t control as well
Spanish herds all on same ration
- All herds feed the same thing
- *if ration alone was what determined milk production=would assume all the yields would be the same
What does increasing age at 1st calving do to production?
- Decreases production
o Get more adipose tissue laid in the udder=reduced ability to produce milk
What does increasing stalls/cow do to production?
- Increases production
What does pushing up feed do to milk yield?
- 3.8kg more milk
What is feed refusals?
- when you feed the next time, there is still feed in the feed bunks
- *continually having food in front of them
What does feed refusals to milk yield?
- 1.6 kg more milk
What are the 2 different feeding systems?
- Component feeding
- Total mixed ration
Component feeding
- Ad-lib feeding of forage
- Concentrates fed separately
o Milking parlour
o Computer feeders
o Individual feeding ‘station’
What are the disadvantages with component feeding system?
- Concentrates may be taken in during short timeframe
- Rumen pH fluctuations
- Competition leading to grain overload
What is partial mixed ration?
- Some grain is fed in parlor
- *most of grain is mixed with forage
Total mixed ration systems
- All feed components mixed to form TMR
- Composition of diet tightly regulated
- *appropriate mixing is critical
What happens with inadequate mixing in TMR?
- Sorting and rumen pH fluctuations
What happens with overmixing in TMR?
- Put it into a powder
- Small particles leading to grain overload and/or frothy bloat
What are the 7 steps for problem solving a dairy ration?
- Characterize low production
- Evaluate Average days in milk
- Evaluate trends in herd size
- Evaluate herd nutritional management
- Evaluate the cows
- Evaluate cow environment
- Additional testing
- *rarely do them all at once
Characterize low production (1)
- Evaluate milk by time and parity
- If low production in heifers:
o Overcrowding, pen moves?
o Small size at calving?
o Over conditioned at calving? - If low production in cows:
o Underfeeding?
o Ketosis, lameness?
Evaluate average days in milk (2)
- Where in lactation is the ‘average’ cow
- Indicator of reproductive efficiency
o If conceives later=longer lactation
o Longer lactations=average cow further in lactation (ex. 200DIM vs. 155DIM) - Increased DIM=decreased milk
Herd investigation example
- Average DIM=240 with 29kg/cow/day
- *addressed reproductive efficiency issue (ex. one bull had a hurt leg)
o New average DIM=180 with 33kg/cow/day - NO ration changes
Evaluate trends in herd size (3)
- Herd expansions decrease milk yield for up to one year
o Hierarchy is diminished at 150-200 cows (before that would have 2 hierarchy groups) - Long vs. short term LOW production
How do health problems effect herd size?
- Death loss
- Reduced herd size
- Reduced milk yield
What is happening with long term LOW production?
- Nutrition problems
- Health problems
- Increased DIM
What is happening with short term LOW production?
- Expansions
- Health problems
- Nutrition problems
Evaluate herd nutritional management (4)
- Determine which cows are eating
- This takes time
- NEVER assume
- Evaluate feed ingredients
- Determine amount fed
- Check mixer scales
- Reconstruct diet
- Evaluate TMR: CAREFUL SAMPLING
Evaluate feed ingredients
- See all feeds
- Understand system
- Analyse dry matter, forage, and grain particles, ensiled feed pH
Determine amount fed
- Interview feeder
- Determine amounts offered and refused
- Weigh everything
Evaluate the cows (5)
- Body condition
- Cud chewing
- Manure evaluation
o ‘if soap you could lather up’ - Lameness
o Increased protein can contribute - Sick cows
Evaluate cow environment (6)
- Can have a minor impact
- Free stalls
- Resting surfaces
- Flooring
- Ventilation
Additional testing (7): HERD TESTING
- Testing alone will never solve a problem
- Test results must be corroborated by other findings
- Rumen pH by rumenocentesis/stomach tube
- Blood tests for ketosis: energy balance
- Blood NEFAs on pre-fresh cows: energy balance
- Urinary pH: hypocalcemia
- Milk urea nitrogen (MUN): protein utilization
Diagnosis and make recommendations
- Individual data can contain error
- Make <3 total recommendations (ideally <1)
- Practical and specific
- Directly related to herd issues
- Related to herd’s goals
- Follow-up
