Feeding Dairy Cattle

Question 1

Does milking cows 3x per day increase or decrease milk production?

Answer 1

increases

Question 2

what is the most common dry period length for dairy cattle?

Answer 2

60 days

Question 3

What are the single highest production cost on a dairy enterprise?

Answer 3

feed costs
- 30-35% total productions costs

Question 4

What are the components of dairy cow diets?

Answer 4

• 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

Question 5

What does alfalfa look like?

Answer 5

Question 6

What kind of plant?

Answer 6

pea

Question 7

We feed a lot of barley (compared to USA where they feed a lot of corn), why?

Answer 7

• Barley grows better here with the cold
• Corn also tends to need more water

Question 8

type of feed?

Answer 8

barley

Question 9

what kind of silage is this?

Answer 9

corn

Question 10

How do you make a balanced ration for dairy cows?

Answer 10

• determine the content of available feedstuffs using Near Infrared (NIR; what is in forage?) & wet chemistry (nutrient balance?)
• determine animal requirements

Question 11

Why is dry matter important?

Answer 11

it is critical for milk production

Question 12

DMI vs milk production rules of thumb?

Answer 12

6kg tax (4.5 kg for Jerseys)
- 6 kg is needed just for walking around everyday
remaining intake x2 = milk yield

Question 13

What drives dry matter intake in dairy cows?

Answer 13

• bodyweight, milk production, body condition, implants

Question 14

what limits dry matter intake in dairy cows?

Answer 14

Ration NDF (neutral detergent fiber), ration NE (net energy), forage mass/allowance, ration crude protein/total digestible nutrients (CP/TDN)

Question 15

What environmental factors affect dry matter intake in dairy cows?

Answer 15

air temperature, plant toxins, water intake & requirements

Question 16

Why are feeding systems important?

Answer 16

because they are getting the ration to the cows

Question 17

What is the 3 diets concept in dairy cows?

Answer 17

• formulated, delivered, consumed

Question 18

Why does feed intake range vary & how does this affect milk production range?

Answer 18

• 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

Question 19

What is important about component feeding systems for dairy cattle?

Answer 19

• ad-lib feeding of forage
• concentrates are fed separately (milking parlour, computer feeders, individual feeding station)

Question 20

What are the disadvantages of component feeding systems for dairy cattle?

Answer 20

• concentrates may be taken in during short timeframe
• rumen pH fluctuates
• competition leading to grain overload

Question 21

How do total mixed ration (TMR) systems work in dairy cows?

Answer 21

• all feed components are mixed
• composition of diet is tightly regulated

Question 22

How does partial mixed ration (PMR) work in dairy cows?

Answer 22

• some grain fed separately in parlour

Question 23

why is appropriate mixing critical in total mixed ration systems?

Answer 23

• inadequate mixing leads to sorting & rumen pH fluctuations
• overmixing leads to small particles which can cause grain overload &/or frothy bloat

Question 24

What is the issue with this ration?

Answer 24

• not well mixed
• clumps of forage & clumps of grain
• cows can sort through & pick what they want

Question 25

How to problem solve in dairy production?

Answer 25

- most common nutritional role of a DVM - 7 step process - rarely do them all at once

Question 26

How do you characterize low production?

Answer 26

- evaluate milk production by time & parity

Question 27

What could cause low production in heifers?

Answer 27

- 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

Question 28

What could cause low production in cows?

Answer 28

- underfeeding? - ketosis, lameness?

Question 29

How do you evaluate the average days in milk?

Answer 29

- 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

Question 30

What else could you address during herd investigation?

Answer 30

reproductive efficiency issue (like injured bull)

Question 31

How long can herd expansions decrease milk yield?

Answer 31

up to 1 year

Question 32

How big does a group of cows have to be before the social hierarchy falls apart?

Answer 32

- Dairy cows can remember 70-80 other cows (can be up to 2 groups in a herd so double this - 140-160)

Question 33

What can cause long term low production in a dairy herd?

Answer 33

- nutrition problems - health problems - increased days in milk (DIM)

Question 34

What can cause short term low production in a dairy herd?

Answer 34

- expansions - health problems - nutrition problems

Question 35

How do you evaluate herd nutritional management?

Answer 35

- 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)

Question 36

what do you evaluate when evaluating dairy cows?

Answer 36

- body condition, cud chewing, manure evaluation, lameness, sick cows

Question 37

what do you evaluate when evaluating dairy cows environment?

Answer 37

- can have a major impact - freestalls, resting surfaces, flooring, ventilation

Question 38

What is important about herd testing in dairy cows?

Answer 38

- testing alone will never solve a problem - test results must be corroborated w/ other findings

Question 39

What should you test for in a dairy cow herd?

Answer 39

- 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

Question 40

How do you diagnose & make recommendations for a dairy herd?

Answer 40

- remember that individual data can contain error - make < 3 total recommendations (ideally 1) - practical & specific - directly related to herd issues & herd goals - follow-up