Feeds and Feeding Exam 3

What is the most important factor that determines the productivity of a lactating diary cow?

feeding

Feed represents what % of the total costs of milk production?

50%

More variation exists in _____ content than ____ among various forages and concentrates

protein; energy

What should be used to balance dairy cow rations?

NEl, CP, and fiber content

T/F A producing dairy cow can not eat enough forage to meet her nutrient needs during lactation

TRUE

What are the best ways to maximize forage consumption in diary cows?

by feeding several times a day and provide a variety of forage

What do concentrate mixtures include?

grains, milk feeds, protein supplements and minerals

What does the mixture fed to dairy cows will depend on?

the forage being fed, availability, and costs

What does the amount of concentrate fed depend on?

amount of forage consumed, amount of milk produced, and composition of milk produced

To what % should concentrate be limited to regardless of comparative costs?

65%

When there is more than 65% concentrate, it causes a change in VFA production, which causes what?

Decreases milk fat

What is the intake of concentrates affected by?

palatability and the time available to consume feed

T/F Requirements vary with phase of lactation and gestation

TRUE

When does milk production peak?

6-8 weeks (45-60 days)

To keep up with milk production, you should increase grain intake to meet energy requirements, but never over __%

65%

What can be fed to allow for more efficient use of body fat for milk production since cows are usually losing BW?

extra protein

During early lactation, what should urea be limited to?

.4-.5 lbs/day

How long into lactation is maximum intake reached?

12-14 weeks

What is the goal when feeding dairy cows?

keeping a cow at peak milk production as long as possible

During peak lactation, grain intake may reach ___% BW, and forage intake should be at least ___% BW to maintain rumen function

2.5%; 1-1.25%

What is another important feeding practice during peak lactation?

feed several times a day

During mid to late lactation, what is important factors to consider?

cow is pregnant, and milk production is reducing

What is important to aviod during mid to late lactation?

over conditioning

Why is it important to match grain intake to milk production?

to avoid wasting grain

When is forage more important: during the dry period or during lactation?

during lactation

During the dry period DM intake should be ___% of BW

2%

How many weeks before calving should grain intake be increased to prevent ketosis?

2 weeks

What should be done to prevent milk fever during the Dry period?

feed low Ca ration

How long is the dry period (depending on age and physical condition)?

4-8 weeks

What are symptoms of ketosis?

high blood and urine ketone levels, low blood sugar, depleted glycogen reserve, lack of appetite

Why are you unable to give a ruminant glucose to treat ketosis?

microbes eat first

What is best for treating ketosis?

propylene glycol (steroids)

What cows are most likely to get ketosis?

high producing cows

When a high-producing cow begins using body fat, what is produced?

acetoacetic acid 

A build-up of what two compounds cause ketosis?

beta-hydroxybutyrate and acetone

What can be done to prevent ketosis in cattle that are prone?

feed high-quality feed before calving and increase with lactation

What is milk fever correlated with?

number of lactations

The chance of milk fever of ___x greater in cows with more than __ lactations compared to those in the first latation

50; 6

___% of milk fever cases occurs at or within 24 hours of parturition

75%

What are symptoms of milk fever?

drowsy, head turns into flank

What are treatments for milk fever?

IV Ca

What are preventative mesures for milk fever?

low Ca diet 2-3 weeks before calving, vit D before calving, and decrease DCAD

Dairy concentrate should contain:

energy, protein, .5-1% trance mineral, 1-2% Ca-P supplement, no more than 6% molasses, no more than 1% ure

What is rumen un-degrated intake protein (UIP)?

by-pass or escape protein`

What are the advatanges for usind DIP/UIP?

decrease overall CP in diet and reduce cost of ration

What does the urea fermentation potential measure?

the usefullness of urea is a ration

What does urea fermentation estimate?

the g urea/kg of DM that can be converted to microbial protein

What is the urea fermentation potential dependent on?

energy in the diet 

What does a negative urea fermentation potential value mean?

that no protein would be synthesized with the addition of urea in the diet because of the energy available

What is bovine somatotropin (BST)?

a natural product produced in the pituitary (GH)

How is BST administered?

subQ every 14 days

At what time of lactation is BST approved for use?

after 9th week of lactation

Injection of BST results in:

immediate (2-3 day) increased milk production, nutrients directed to the mammary gland, and increased intake

When injecting BST, DM intake increases how long after injection?

3-6 weeks

How much does DM intake increase after injecting BST?

3-5 lbs/day

What does injecting BST usually result in?

decreased body condition

How does BST effect reproduction?

increased open days, reduced pregnancy rate, increased twinning, increased lameness, and increased mastitis 

What are the three things needed for to produce microbial protein?

ammonia, carbon skeleton, and energy

What are the two sources of protein?

true protein and non-protein nitrogen

What is the goal when formulating a sheep ration?

Provide optimal production, be efficient, be economical, decrease nutritional disorders

What is the most limiting nutrient for sheep?

energy

What can an energy deficiency in sheep cause?

cessation of growth, weight loss, reproduction failure, decreased survival, and decreased resistance to parasites

When is protein most important in sheep?

when they are young and growing

Why is selenium important to manage in sheep?

It has the narrowest range between being deficient and being toxic

What does a deficiency in selenium cause in sheep?

Stiff lamb disease and white muscle disease

When does stiff lamb disease occur?

Before 2 weeks of age

When does white muscle disease occur?

between 2-8 weeks of age

Se supplementation should not proceed what ppm in sheep?

0.1 ppm

What amount of selenium must be consumed for it to be toxic in sheep?

2 ppm

Meat from a sheep over 1 year old

mutton

Meat from a sheep under 1 year

lamb

What are the three critical periods (nutritionally) in sheep?

flushing, the last 6 weeks of gestation, and the first 8 weeks of lactation  

How long before breeding should feed be increased for flushing in sheep?

3 weeks

Why is nutrition important during the last 6 weeks of gestation in sheep?

full abdominal cavity, developing fetus, at risk for pregnancy toxemia

When are these critical periods even more important for sheep?

When farms use accelerated lambing programs (3 lambing/ 2 years)

When is creep feeding beneficial for lambs? 

early weaned lambs (<60 days), Fall and winder born lambs (out of seasons), twin lambs, late lambs, drought

What are important things to remember when formulating creep feeds for lambs?

Ratio should be very palatable, less than 15% CP, started as soon as possible, and pellets are preferred

What are considerations for finishing lambs?

level of performance, kind of lamb, grain source, and costs

In lamb rations, wheat should not make up more than what %?

50%

What is the most expensive up-front cost of farming?

land

Why raise sheep?

less land, less investment, and they can be grazed complementary with other livestock

What causes entertoxima?

High CHO intake, which causes a change in pH, which triggers clotridium perfingens type D to produce toxins

What can be done to prevent enterotoxmia in sheep?

vaccine

Where does polioencephalomalacia occur most often in sheep?

feedlots

What causes polioencephalomalacia?

thiamine deficiency

What initiates the thiamine deficiency associated with polioencephalomalacia?

Rumen-produced thiaminases which occur with a pH decreases in the rumen

What are the symptoms of polioencephalomalacia?

disoriented, circling, progressive blindness, head pressing, and death