Lecture 19: Dairy Nutrition 3 (Exam 2) Flashcards
Which amino acids are limiting in most feeds
- Lysine & methionine
What are ways to provide extra lysine & methionine
- Soybean meal
- Dried brewers grain
- Blood/fish meal
- Rumen protected AA may be fed
As dietary protein intake increases what happens to Nitrogen
Nitrogen excretion as urea in urine increases
What should be added for protein fermentation to max N utilization by bacteria
To match the carbs to the protein fermentation
Describe protein levels in dairy rations
- 16 - 18% high quality protein
- Need to look @ AA profile & bypass protein
What are the consequences of overfeeding protein
- Infertility (any access ammonia or urea can delay maturation of the oocyte or of any dev embryos)
- Lameness (if there is excess protein it can lead to bacterial fermentation products that impact foot health)
Why is the balance btw RDP/NPN & energy levels in the rumen important
- B/c microbes need energy from the diet to use nitrogen from the diet & avoid ammonia accumulation
- Increasing ammonia in the rumen leads to an increase of ammonia in the blood
What can happen in the liver due to wrong CHO (energy): RDP/NPN
- Can limit the livers ability to convert ammonia to urea
- Leads to increase BUN
How does high potassium in forages affect Ca
- Negatively
- Affects calcium homeostasis in transition & early lactation cows which can increase incidences of milk fever
How does high potassium in forages affect Mg
- Negatively affects ava of Mg in forages
- High potassium in soils causes decrease in Mg uptake by plants which increases incidence of hypomagnesemic tetany (grass tetany)
T/F: Ca: P ratio is more important than meeting reqs for Ca & P
False; the ratio is not as important as meeting reqs for Ca & P
What are the reasons we would have to supplement phosphorus
- Ca > P in leaves & stems of plants
- More common Than a Ca deficiency
- P deficient soils are more common
- P levels in plants drop faster than Ca as plants mature
What happens to excess Phosphorus
Excreted via milk & feces
What is the recommended amount of phosphorus in the diet
- .35%
- Going above .45% is unnecessary
How much water should cows intake
- 2 to 4 lbs of water for every lb of DMI
- Need an additional 3 to 5 lbs of water per lb of milk
What are the guideline for providing water to cows
- Need 2 inches per cow
- Water needs to be @ least 3 inches deep
- Height of the trough needs to be 24 to 32 inches
- Need one trough or watering device per 15 - 20 cows so that bullying will not occur
- Prefer room temp water
What should a dry cows ration look like
- Low energy ration w/ adequate protein, vitamins, & minerals (little to no grain)
- Increase their energy starting3 Ws before calving (transition period
- Want to have a BCS of 3 to 4
What are the two approaches for feeding dry cows
- Adapt rumen to grain diet
- Level/consistent NDF feeding
What is the adapt rumen to grain diet
Adapt the rumen to a high grain diet before calving
What is the level/consistent NDF feeding
- Need to maintain rumen’s ability to digest fiber
- Feed very low energy high fiber ration through to calving & then add grain
Why is it important to maintain DMI in close up dry cows
Need to maintain DMI in close up dry cows b/c we need to have adeq energy reserves for 6 to 8 weeks after calving
