Feeding Dairy Cattle Flashcards
Does milking cows 3x per day increase or decrease milk production?
increases
what is the most common dry period length for dairy cattle?
60 days
What are the single highest production cost on a dairy enterprise?
feed costs
- 30-35% total productions costs
What are the components of dairy cow diets?
- symbiosis btwn cow nutrition & rumen microbial health
- fiber sources for milk fat production: Alfalfa silage, pea silage, grass silage
- grains for gluconeogenesis: barley, corn
- some feeds provide both: corn silage, barley silage
What does alfalfa look like?
What kind of plant?
pea
We feed a lot of barley (compared to USA where they feed a lot of corn), why?
- Barley grows better here with the cold
- Corn also tends to need more water
type of feed?
barley
what kind of silage is this?
corn
How do you make a balanced ration for dairy cows?
- determine the content of available feedstuffs using Near Infrared (NIR; what is in forage?) & wet chemistry (nutrient balance?)
- determine animal requirements
Why is dry matter important?
it is critical for milk production
DMI vs milk production rules of thumb?
6kg tax (4.5 kg for Jerseys)
- 6 kg is needed just for walking around everyday
remaining intake x2 = milk yield
What drives dry matter intake in dairy cows?
- bodyweight, milk production, body condition, implants
what limits dry matter intake in dairy cows?
Ration NDF (neutral detergent fiber), ration NE (net energy), forage mass/allowance, ration crude protein/total digestible nutrients (CP/TDN)
What environmental factors affect dry matter intake in dairy cows?
air temperature, plant toxins, water intake & requirements
Why are feeding systems important?
because they are getting the ration to the cows
What is the 3 diets concept in dairy cows?
- formulated, delivered, consumed
Why does feed intake range vary & how does this affect milk production range?
- increased age at first calving = decreased production
- increase in stalls/cow = increased production
- pushing up feed increases milk production
- feed refusals (when you come to feed the next time there is still feed in the feeder) means there is continuously feed available & they are going to eat more & produce more milk
What is important about component feeding systems for dairy cattle?
- ad-lib feeding of forage
- concentrates are fed separately (milking parlour, computer feeders, individual feeding station)
What are the disadvantages of component feeding systems for dairy cattle?
- concentrates may be taken in during short timeframe
- rumen pH fluctuates
- competition leading to grain overload
How do total mixed ration (TMR) systems work in dairy cows?
- all feed components are mixed
- composition of diet is tightly regulated
How does partial mixed ration (PMR) work in dairy cows?
- some grain fed separately in parlour
why is appropriate mixing critical in total mixed ration systems?
- inadequate mixing leads to sorting & rumen pH fluctuations
- overmixing leads to small particles which can cause grain overload &/or frothy bloat
What is the issue with this ration?
- not well mixed
- clumps of forage & clumps of grain
- cows can sort through & pick what they want
How to problem solve in dairy production?
- most common nutritional role of a DVM
- 7 step process
- rarely do them all at once
How do you characterize low production?
- evaluate milk production by time & parity
What could cause low production in heifers?
- overcrowding, pen moves?
- small size at calving?
- overconditioned at calving?
(smaller size & overcrowding will cause more subordinate heifers to be pushed away from the feed bunk
What could cause low production in cows?
- underfeeding?
- ketosis, lameness?
How do you evaluate the average days in milk?
- where in lactation is the “average” cow?
- indicator of reproductive efficiency (conceives later = longer lactation = average cow further in lactation)
- decreased days in milk (DIM) = decreased milk
What else could you address during herd investigation?
reproductive efficiency issue (like injured bull)
How long can herd expansions decrease milk yield?
up to 1 year
How big does a group of cows have to be before the social hierarchy falls apart?
- Dairy cows can remember 70-80 other cows (can be up to 2 groups in a herd so double this - 140-160)
What can cause long term low production in a dairy herd?
- nutrition problems
- health problems
- increased days in milk (DIM)
What can cause short term low production in a dairy herd?
- expansions
- health problems
- nutrition problems
How do you evaluate herd nutritional management?
- determine what cows are eating
- this takes time
- NEVER ASSUME!
- evaluate feed ingredients (see all feeds; understand system; analyze dry matter, forage & grain particles, ensiled feed pH)
- determine amount fed (interview feeder; determine amounts offered & refused; weigh everything)
- check mixer scales
- reconstruct diet (rebuild from scratch)
- evaluate TMR (careful sampling)
what do you evaluate when evaluating dairy cows?
- body condition, cud chewing, manure evaluation, lameness, sick cows
what do you evaluate when evaluating dairy cows environment?
- can have a major impact
- freestalls, resting surfaces, flooring, ventilation
What is important about herd testing in dairy cows?
- testing alone will never solve a problem
- test results must be corroborated w/ other findings
What should you test for in a dairy cow herd?
- rumen pH by rumenocentesis/stomach tube
- blood tests for ketosis: energy balance
- blood non-esterified fatty acids (NEFAs) on pre-fresh cows: energy balance
- urinary pH: hypocalcemia
- milk urea nitrogen (MUN): protein utilization
How do you diagnose & make recommendations for a dairy herd?
- remember that individual data can contain error
- make < 3 total recommendations (ideally 1)
- practical & specific
- directly related to herd issues & herd goals
- follow-up
