19. Dairy Nutrition 3

1. protein utilization efficiency

2. mineral balance and interactions

3. adequate water intake

4. proper dry cow management

what are the big picture nutritional properties of dairy cows

lysin and methionine

what are the two limiting AA in most feeds

ideal AA profile

what do microbial protein help to acheive

RUP (bypass protein)

what helps to meet AA needs...primarily add soybean meal or fish meal to help

corn gluten meal

based on this chart, which form of concentrate will help meet general methionine requirements

soybean meal

based on this chart which concentrate will best help meet lysine requirements for tissues

fish meal

based on this chart, which concentrate will most closely meet the lysine requirements of bacteria and mil and also meet general methionine requirements

soybean meal, distillers grains, fish meal

what are the primary protein sources involved in dairy cow nutrition

fish meal and blood meal

which concentrate inclusions are limited due to issues with palatability

fiber digestion

high fat sources may impair what

16-18% CP

what is the CP requirement in a typical diet (remember it is higher in early lactation)

microbes require energy + nitrogen simultaneously but an imbalance can cause ammonia accumulation in the blood (from the nitrogen) and lead to urea production

why is it essential to match energy and protein supplies

mismatch will lead to wasted protein

key point with matching energy and protein supplies it that...

1. increased urinary nitrogen excretion

2. infertility and lameness risk-->delay maturation of oocytes or embryo development

3. environmental nitrogen loss

consequences of excess protein

nitrogen balance

BUN and MUN serve as indicators of...

10-20 mg/dL

acceptable BUN range

<10-12 mg/dL

acceptable MUN range

excess RDP (rumen digestible protein) or poor CHO (carb) balance

high BUN and MUN values correspond with....

can overwhelm the liver's ability to convert to non-toxic urea

what happens in the event there is excess NH4

fish meal

what concentrate can supplement lysin and methionine but is not very palatable

1. Ca, P, Mg--->often all supplemented

2. K, Cl, S

what are the major minerals in dairy cow nutrition

decrease Ca mobilization (movement from bone, GIT, kidney) causing milk fever/hypocalcemia

what does high K lead to in terms of Ca

decreased Mg absorption leading to grass tetany

what does high K lead to in terms of Mg

true availability is only about 45%

why is calcium often supplemented above its requirements of 0.62%-0.67%

increase Ca and Mg needs because insoluble soaps form between Ca and Mg and the FAs in the SI making the unavailable for absorption

how do high fat diets impact Ca and Mg needs and why

ensuring requirments for Ca and P are met

what is more important, Ca:P ratio or ensuring requirements for Ca and P are met

reduce

excess Ca can (increase/reduce) availability of a wide range of minerals

1. often deficient in soils and plants so it needs to be supplemented

2. required for milk production

what is the importance of phosphorus

excreted in feces...environmental concern

how is excess P excreted

0.3-0.4%

what is the phosphorus requirement in dairy cows

research shows increased P does NOT increase milk yield and is only excreted in feces at greater amounts

why is over supplementation (0.45%) of P considered unnecessary

magnesium

which mineral is affected and K (potassium) increases and is related to grass tetany

1. most important nutrient

2. essential for milk production

importance of water

2-4 lb water/lbs DMI

what is the water intake requirement on a DMI basis

+3-5 lb water/lbs milk

how does water intake requirement change during lactation

1. milk yield

2. DMI

3. temperature and humidity

4. water quality and availability

what are some factors that can affect water intake

1. adequate access and space...one trough per 15-20 cows

2. clean palatable water

3. most intake after feeding/milking...recognize the busy times

what are key parts of water management

nitrates, sulfates, algae

what are the risks associated with water

blue-green algae

what specific algae did we discuss that can kill a cow if in their water

reduced intake

what happens to intake when water quality is poor

1. maintain BCS of 3-4 in order to maintain adequate reserves for 6-8wks post calving

2. maintain DMI

3. avoid excess energy....little to no grain as she enters transition phase

goals of dry cow feeding

last 3 wks pre-calving and first 3 wks post calving consisting of decreased intake but an increased demand for energy...need to slowly increase energy density of ration

what is the transition period

high-risk period for metabolic disease

significance of the transition period

1. feeding strategy 1/ adapt to grain pre-calving

2. feeding strategy 2/ high fiber rations

what are the two feeding strategies for transition cows

1. introduce grain pre-calving to prepare rumen for lactation diet

2. increased energy density compensates for drop in DMI

3. goal is rumen adaptation, advantage is smooth transition

what is important to recognize about strategy 1/ adapt to grain feeding strategies for transition cow

1. maintain high NDF diet and add grain after calving

2. fiber buffers rumen pH to help avoid rumen acidosis when grain is added

3. goals is rumen stability, advantage is lower acidosis risk

what is important to recognize about strategy 2/ high fiber feeding strategies for transition cow

balanced

protein must be _____ for efficency

fertility and enviornemnt

excess nitrogen negatively affects ___ and ____

mineral interactions

___ ___ are clinically important

production

water intake directly impacts ____

next lactation

dry cow nutrition sets up ____