Feeds Exam 3

Persistency

The amount of milk produced today compared to the amount of milk produced yesterday

What two things determine nutrient requirements for dairy cows

1. Maintenance

2. Lactation

What are the two components that make up lactation requirements

1. Fat content of milk

2. Amount of milk produced

Feeding lactation dairy cattle determines what?

Their productivity

Feed represents how much of a dairy’s costs?

50%

Nutrient requirements for maintenance compared to lactation

Requirements for lactation are usually several times that of maintenance

Dairy cow forage intake during lactation

They cannot eat enough forage to meet their nutrient requirements

Ways to stimulate forage intake in dairy cows

1. Feed several times a day

2. Provide a variety of forages

Why is silage used in the dairy industry

As a way to provide different/variety of forages

Concentrate mixes for dairy include what

1. Grains

2. Protein supplements

3. Minerals

4. Feeds that help milk production

The type of concentrate mix depends on

1. Forage being fed- protein content

2. Availability

3. Costs

The amount of concentrate mix fed depends on

1. Amount of forage consumed

2. Amount of milk produced

3. Composition of milk

Concentrates are limited to a max of ___. Why?

65% to avoid negative associative effects

Greater than this will alter VFA production in rumen leading to a decrease in milk fat

Intake is affected by

1. Palatability- Particle size and rustiness

2. Time available to consume

Early lactation characteristics

1. Milk production increases rapidly

2. Peaks at 6-8 weeks after calving

Early lactation feeding

1. Increase grain intake to meet energy requirements

2. Extra dietary protein

3. Limit urea to .4-.5 lbs a day

Why is protein supplied during early lactation

Allows for more efficient use of body fat for milk production

Peak lactation characteristics

1. Want to keep cows at peak for as long as possible

2. Reach max intake at 12-14 weeks

Peak lactation feeding

1. Grain intake may reach 2.5% BW

2. Forage intake should be at least 1-1.25% BW

3. Feed several times a day

Mid-late lactation characteristics

1. She is pregnant

2. Milk production starts to decline

Mid-late lactation feeding

1. Match grain intake to milk production

2. Avoid wasteful grain feeding to low producers

3. Avoid over conditioning

Dry period feeding

1. Forage quality not as critical

2. DM intake ~2% BW

3. ~2 weeks before calving increase grain feeding to decrease ketosis

4. Feed low Ca diet to prevent milk fever at calving

Dry periods should last how long

4-8 weeks

Depends on age and physical condition

Ketosis is what type of issue

Metabolic issue

Ketosis is caused by what

Not enough glucose for energy so the body starts to break down fat which forms ketone bodies

Acetoacetic acid→ beta-hydroxybutyrate and acetone → ketosis

Ketosis characteristics

1. High blood and urine ketone levels

2. Low blood sugar

3. Depleted glycogen reserves

4. Lack of appetite

How to treat ketosis

Feed glucose precursors

Propylene glycol is best

Cattle prone to ketosis can be fed how to help prevent it

Fed high quality before calving then increase substantially after parturition

What is milk fever

Hypocalcemia

Milk fever characteristics

1. Correlated with the number of lactation

2. 75% of case occur at or within 24 hrs of calving

Milk fever symptoms

1. Drowsy

2. Head turns into flank

How do you treat milk fever

With IV Ca

Ways to prevent milk fever (and potential issues with each)

1. Feed low Ca diet 2-3 weeks before calving (can be difficult to find because forages are high in Ca)

2. Give vitamin D before calving (can be toxic so need to know exact calving date)

3. Decrease DCAD- the ratio of cations to anions

When feeding young heifers for for milk production remember to also feed enough for

1. Growth

2. Maintenance

3. Milk production

Considerations when feeding for milk production

1. It is best to group cows based on production level- heifers seperate

2. More cows are underfed on energy than protein

3. Fiber requirements

4. Make-up of concentrate mix

5. Best to feed some hay with silage

6. Relationship of feed with milk flavor

Fiber requirements for milk production

1. CF ~17%

2. ADF ~21%

3. NDF ~35%

Concentrate mix should include

1. Energy

2. Protein

3. 0.5-1% trace mineralized salt

4. No more than 6% molasses

5. No more than 1% urea

Cows will consumer how much water per lb of milk produced

3-5 lbs of water per 1 lb of milk

Feeds that may effect milk flavor

1. Molasses- no more than 6% in concentrate mix

2. Wheat- remove several hours before milking

Types of protein for dairy cows

1. Rumen degraded and rumen undegraded intake protein (DIP/UIP)

2. Urea fermentation potential

Advantages of using DIP/UIP

1. Decreases overall CP in diet

1. Results in reduced cost of ration

Urea fermentation potential

1. Evaluation of the useful urea in a ration

2. Estimation of urea that can be converted to microbial protein

3. g urea/ kg diet

A negative value for urea fermentation potential indicates what

No protein would be synthesized with available energy

Bovine somatotropin

SubQ injection every 14 days starting at 9th week of lactation to increase persistency

BST is only given to what dairy cows

Only medium quality / poorer milking cows

Not given to high producing cows

BST injection results in

1. Immediate increase in milk production for 2-3 days

2. Nutrients directed from body tissues to mammary glands

3. Need for increased intake → DM intake will not increase until 3-6 weeks after injections

BST milk production increase amount

8-22%

5-15 lbs/day

BST effects on reproduction

1. Increased days open → reduced pregnancy rate

2. Increased twinning

3. Increased lameness

4. Increased mastitis

Sheep rations should

1. Provide for optimal production

2. Be efficient

3. Be economical

4. Decrease nutritional disease

What is usually the most limiting factor in sheep nutrition

Energy

Energy deficiencies in sheep

1. Cessation of growth

2. Weight loss

3. Reproductive failure

4. Decreased survival

5. Reduced resistance to parasites and disease

Protein is most important in what type of sheep?

Young and growing sheep

(T/F) NPN can be utilized by sheep

True

Selenium deficiency in sheep

1. Stiff lamb disease/muscular dystrophy

2. White muscle disease after 2-8 weeks of age (Reduced growth)

Se supplementation cannot exceed how much of the total ration

0.1 ppm

Se toxicity occurs when sheep consume how much? Symptoms?

More than 2 ppm in diet

Tetanus like symptoms

Western sheep flocks

1. Usually larger, range flocks

2. Ewe wool producers who also produce meat lambs

3. Less predation

Eastern sheep flocks

1. Smaller flocks

2. Brought in during night- more predation

3 critical periods for sheep

1. Flushing- 2-3 weeks before breeding

2. Last 6 weeks of gestation

3. First 8 weeks of lactation

Flushing in sheep

1. Increase energy prior breeding

2. Very responsive- increased ovulation rate

3. Will not necessarily increase number of lambs born

4. Sheep in good condition will probably not respond

Why are the last 6 weeks of gestation critical in sheep?

1. Developing fetus

2. Want to avoid pregnancy toxemia

What is pregnancy toxemia and what causes it?

It is ketosis caused by an enlarged uterus pressing against the rumen reducing its capacity

Usually in lambs carrying twins or triplets

Requirement during a sheep’s first 8 weeks of lactation depends on what?

The number of lambs born

Accelerated lambing programs

1. Usually 3 lambing every 2 years

2. Critical periods even more critical

Creep feeding is recommended for what lambs?

1. Early weaned (<60 d)

2. Fall and winter lambs

3. Purebred and registered

4. Twin and late lambs

5. During drought or on range

Creep feed should be

1. Very palatable

2. <15% CP

3. Started as soon after birth as possible

4. Pelleted is preferred

What is the biggest factor when deciding to creep feed lambs

If it is economical

Considerations when finishing lambs

1. Level of performance (Optimal not max)

2. King of lamb (Meat vs wool)

3. Grain source

4. Protein source

5. cost of feed

6. Costs of lambs

Wheat should not make up more than __ of a lambs total grain

50%

Will get sticky/clump together

Ways to reduce dustiness of ground wheat

1. Molasses

2. Pelleting

Why choose sheep to raise?

1. Less investment- smaller, need less land

2. Complimentary grazing with cattle- enhances productivity per land unit

Nutritional disorders in sheep

1. Enterotoxemia

2. Polioencephalomacia

Enterotoxemia in sheep

1. overeating disease or pulpy kidney disease

2. Eating high levels of readily available CHO C. perfingens type D multiplies rapidly and produces a toxin

Polioencephalomalacia occurs most in what type of sheep?

Feedlot lambs

Symptoms of polioencephalomalacia

1. Disoriented

2. Circling

3. Progressive blindness

4. Occasional head pressing

What is polioencephalomalacia

Thiamine deficiency

Rumen produced thiaminases continually breakdown thiamine that the sheep is producing so they do not have enough to utilize