Final Review

Question 1

Volume of Rumen

Answer 1

• 50 gallons

Question 2

VFAs

Answer 2

• produced by microbes in rumen
• acetic, propionic, and butyric acid

Question 3

Methane Formation

Answer 3

• H2 + CO2 produced by microbes = CH4
• released thru eructation, otherwise rumen pH would decrease

Question 4

Peak Dairy Cattle Lactation

Answer 4

• day 60
• after which, lactation decreases

Question 5

Lactation, Body Weight, and Feed Intake Curve for Dairy Cattle

Answer 5

• dry matter intake increases with increase in lactation
• body weight decreases at beginning of lactation and slowly increases (has another growing calf inside her during late lactation period)

Question 6

Feed for Dairy Cattle

Answer 6

• 50% roughage, 50% concentrates
• comes from byproducts of plant production
• 20% of plant material produced in CA are given to cows (high quality nutrition)
• part of the reason why CA has so many dairy cattle

Question 7

Total Mixed Ration (TMR) for Dairy Cattle

Answer 7

• formulated diets for dairies
• depends on feed access
• differs throughout the year
• made up by nutritionist
• rare to have whole herd on same diet

Question 8

Roughage

Answer 8

• primary feed for dairy cattle
• bulky feed
• low digestibility
• high crude fiber
• low energy
• variable protein content
• store through hay and silage

Question 9

Alfalfa

Answer 9

• high in protein because of rhizobium symbiosis (nitrogen fixers –> proteins)
• very expensive
• needs lots of water
• can be made into dried hay that doesn’t rot because of low moisture content

Question 10

Silage

Answer 10

• whole plant cut into pieces, tractor drives over each layer to remove air and limit aerobic microbes
• white tarp weighed down over silage
• 4 days later, aerobic microbes have consumed all the oxygen and are replaced by lactic acid forming microbes
• lactic acid produced decreases pH of silage from 7 to 4, making conditions bad for other microbes to grow

Question 11

1 Silage in CA

Answer 11

• corn silage

Question 12

Dairy Feeding Ration

Answer 12

• 1/2 is stored in hay or silage

Question 13

Energy Concentrates

Answer 13

• cereal grains, molasses, fats/oils
• high digestibility
• low crude fiber
• moderate protein
• high energy

Question 14

Protein Concentrates

Answer 14

• animal: blood, bone, fish meal; dry milk powder
• plant: soybean/canola/cottonseed meal, sunflower/cottonseed, dried distillers grains

Question 15

Dried Distillers Grains (DDG)

Answer 15

• most often fed
• byproduct of ethanol produced for fuel by corn
• solids from ethanol become DDG

Question 16

Corn in US Destination

Answer 16

• majority to fuel
• 5-10% of gasoline is ethanol, which comes from corn
• 40% of corn produced goes to fuel
• 5% of corn produced goes to cattle

Question 17

Lipids

Answer 17

• seeds, byproducts, supplements
• energy dense (9 kcal/g compared to 4 kcal/g for carbs and proteins)
• can’t exceed 6% of dairy diet

Question 18

Dairy Cattle Vitamins

Answer 18

• need fat-soluble vitamins thru diet
• A, D, E, K
• don’t need Vitamin B from diet

Question 19

Minerals

Answer 19

• 21 essential
• macro: need large intake of
• micro: small intake
• mineral deficiencies in soil supplemented by salt licks

Question 20

Water

Answer 20

• clean, fresh, available, convenient
• one water space (2 ft of tank perimeter) for every 15-20 cows
• 2+ watering locations for larger groups

Question 21

Starter Feed For Calves

Answer 21

• high in energy
• 15-18% crude protein
• hay, hay + grain, all grain + protein pellet

Question 22

Dairy Heifers

Answer 22

• good to high quality roughage
• breed at 14-15 mo
• 1st calf at 2 yo

Question 23

How to/why accustom heifers and cows to lactating diet?

Answer 23

• add concentrates to diet in last 2-3 weeks pre-calving (5-8 lbs per cow per day)
• need to adjust microbial population to fresh cow
• reduce ketosis incidence

Question 24

Springers

Answer 24

• heifers w/in 2-3 mo of calving

Question 25

Ca in Diet of Dairy Cows

Answer 25

• reduce Ca in feed so that cow mobilizes Ca from her own body reserves after giving birth to fulfill high Ca demands
• reduction of Ca in cow diet before calving reduces milk fever

Question 26

Body Condition Score of Lactating Cows

Answer 26

• at lactation start: 3.75
• lose 1 BCS that must be restored prior to next lactation
• loss of BCS due to loss of fat
• avoid energy intake deficiency