coursera week 3 DAIRY PRODUCTION AND MANAGEMENT

β-glucans: Soluble fiber found in barley grain By-product: Animal feed, usually a waste product from the food industries Colony-forming units: A measure of the number of viable bacteria

β-glucans: Soluble fiber found in barley grain

By-product: Animal feed, usually a waste product from the food industries

Colony-forming units: A measure of the number of viable bacteria

Ergot: Fungus growing on rye

Ergotamine: Toxin produced by ergot

Extruder: A screw-press used to extract oil from oilseeds and to produce oilseed meal for

animal feed

Flaking of grain: Grain processing involving heat and steam that leads to starch gelatinization

Gelatinization: A process of breaking down the intermolecular bonds of starch molecules in the

presence of water and heat

Ionophoric antibiotic: An antibiotic selectively inhibiting certain microbial species in the

rumen

Mailard reaction: Chemical reaction between amino acids and reducing sugars at high

temperature that gives feeds brown color and flavor (and also decreases protein availability)

Non-protein nitrogen: Nitrogen from mineral source, such as urea

pH: A measure of acidity or basicity of solutions

Rumen-protected: Feed additive that is coated or in some other way protected from attacks by

the rumen microbes

Silage inoculant: A microbial additive used in ensiling to stimulate fermentation (usually lactic

acid) and improve silage quality

Yeast: In animal nutrition, live yeast or yeast culture used as animal feed

Conversion Matrix

1 inch = 2.5 cm

1 kg = 2.2 lbs.

Temperature conversion = Temperature (T) in degrees Fahrenheit (°F) is equal to the

temperature (T) in degrees Celsius (°C) × 9/5 + 32

Hello, my name is Alex Hristov and

I'm a Professor of Dairy Nutrition at Penn State University

The next few lectures we'll discuss specific feeds discussed in dairy rations

First, I will remind you that we classify dairy feeds into two major categories,

forages and concentrate feeds

Forages can be very diverse and with large variation in chemical composition and nutritive value

For example, as plants mature, forages deposit more in digestible material,

such as legume and their nutritive value decreases

Concentrate feeds include grains, oilseeds, by-products and

minerals and vitamin supplements

In addition, in dairy nutrition, we use a long list of feed additives

Examples of feed additives include synthetic amino acids, non-protein

nitrogen, additives such as urea, yeast products, rumen buffers and others

So first, we'll start with foragers, please also remember to listen to Dr

Roth's lectures on dairy forages from an agronomic standpoint

Forages are by far, the most important feeds in a dairy ration

Their quality determines the quality and nutritive value of the entire diet

They are also the most variable in composition components of the diet

Typical forages in dairy ration in countries with temperate climate and

good silage, alfalfa, rice in cool season, warm season grass is for

grazing or silage making [INAUDIBLE] grass and others

In North America, the main formation to the Russian is corn silage

Corn silage will typically have a content of around 33 to 35%

Neutral Detergent Fiber around 45%, crude protein,

8 to 9% and starch can be anywhere from 24 to 38, 40%

Corn silage is usually processed with corn process of during harvest,

the advantages being better in silo fermentation,

low silage losses and increased digestibility

Corn silage is fed to cows as a source of digestible energy from both fiber and

starch

Its protein content, however is low and the true protein is deficient in lysine,

which is a key amino acid in farm animal nutrition

Optimal stage for harvest for corn silage is three-quarters to

one-third milk line in the kernel and about 33 to 35% dry matter

Digestibility of both the stover, which is the fibrous part of the plant and

grain may be higher in early maturity

For example, early dent and 30% dry matter, but total harvest of digestible

organic matter per acre will be lower due to the lower starch content

Silage harvested to high maturity black layer of the kernels and above 37% dry

matter will have decreased starch in total organic matter digestibility

Corn silage can be fed as the sole forage to lactating dairy cows

High quality corn silage is a recipe for successful dairy farming

Main point to remember is that stage of harvest is critically important for

silage quality

Another critical factor for corn silage quality is the process of insiling,

which we'll discuss in a following lecture

The second most important forage in North American dairy diets is alfalfa hay or haylage, which is a forage kind of restricted 40 up to 60% dry matter

It should be pointed out here that there is little to no difference in milk

production between well-preserved silage or haylage and

hay made from the same forage

However, the feeding value of both silage and hay can dramatically decrease

if in silage practices are compromised or field losses are high due to rainfall Recommended silage and

hay making practices will be covered in a separate lecture

Alfalfa is referred to as the queen of forages and

is an extremely valuable crop for dairy cows

Typically, alfalfa haylage will be around 40% dry matter will

have around 18 to 20, 21% crude protein

43 to 45% Neutral Detergent Fiber and will have high levels of calcium and other minerals, considerably more than co-signage

We feed alfalfa as hay or haylage today cows,

because of it´s high digestible protein content

Digestible fiber, calcium and

also digestible non fiber carbohydrates such as pectins

Compared with corn silage, fiber in alfalfa is more rapidly digestible, but

total digestibility will be lower, because of higher content

The high protein count of alfalfa,

particularly haylage is a blessing can curse at the same time

This is because alfalfa protein is highly digestible and converted to a great extent into non-protein nitrogen in the silo, all the rumen and large portion of it

is eventually lost with urine and can not be efficiently utilized by the dairy cow Optimum maturity for harvesting alfalfa is mid to late-bud and

maximum take 10% bloom

Yield per acre will increase with more mature plants, but as with corn silage, the digestibility of the harvested forage will decrease

Other legumes, such as various types of clovers, sainfoin, soybean and

pea forages can also be fed to dairy cows as silage or grass legume pastures Grasses as pasture of silages alone or in combination with legumes

are an excellent source of digestible fiber and energy for dairy cows

In climates without foliage crops such as corn, for example, may not grow well Grasses are the primary foliage for dairy cows

Some reasons to grow grasses include greater seeding year yields,

wider harvest window and second and later cuttings, faster dying time and

as a source of digestible fiber in diets that are high in corn silage and starch Production systems in dairy power houses,

such as New Zealand and Ireland are almost entirely based on grass silage Typical grass silage will have around 40% dry matter,

55 to 60% Neutral Detergent Fiber and 16 to 18% crude protein

Fiber in grass silage is digested at a lower rate, but

to a greater extent than fiber from legumes

This means that grass silage could serve as a source of digestible fiber

in the ration

Species can vary, but in the US most common grasses include perennial and Italian ryegrasses, tall fescue, orchardgrass, thimothy,

bromegrass and others

Recommended stage of harvest is late-buds to early head

In the pasture-based systems of New Zealand, the main forage for

dairy cows is a perennial rye grass/white clover mix

Small grain silages such as barley, wheat, triticale and oats are grown in Northern and temperate climates as forage crops, often as cover crops on dairy farms Typically, this forage is used to make silage that contains around 35% dry

matter, 58 to 60% Neutral Detergent Fiber and 12 to 14% crude protein

These plants are very sensitive to the stage of harvest and their quality and

digestibility

Rapidly declines as the plant matures

These forages are harvested at flat leaf stage, for example,

wheat or early to mid-dough and even early to mid stage barley, and oats

Yields will increase as the plant mature, but

digestibility will dramatically decrease

A number of other forage crops can also find place on a dairy farm for

various reasons, including favorable ergonomic characteristics

For example, drought resistance, early to late harvest,

specific desirable nutrient or nutrients

For example, high sugar grasses species or environmental advantages,

such as high nitrogen and uptake from heavily fertilized soils

In our next lectures, we'll discuss energy and protein feeds, by-product feeds and feed supplements

Hello and welcome back

We'll continue our lectures on feeds for dairy cows

Next we'll discuss concentrate feeds and we'll start with cereal grains

In the U.S and other countries, corn is the main energy grain fed to dairy cows

Of all crops, corn yields the most digestive organic matter per acre

It is highly energetic feed because of its high starch content

It's relatively low protein, around 9%, and about 4 to 5% oil

The oil is high in unsaturated fatty acids

Corn has to be cracked or ground before being fed and

its nutritive value would depend on the method and

extent of processing, which we'll cover in a separate lecture

A similar extent of processing,

degradability of corn starch is lower than most other cereal grains

Which is advantageous in their nutrition, because higher rates of starch

degradability can cause room in lactosis and decreased milk fat test

Corn grain can be safely fed to dairy cows and

can make up the entire concentrate portion of the ration

As all cereal grains, corn is low in calcium and high in phosphorus

Yellow corn is high in beta carotenes, which is a vitamin A precursor

And corn grain can be harvested moist at around 22 to 28% moisture and in salt This is called high-moisture corn and has higher rate and

extent of starch digestibility and energetic value compared with dry corn

Another important grain for dairy cows is barley

Barley is high in protein, around 12 to 13% and

neutral detergent fiber around 20% because of its fibrous hull, than corn

And has compounds that are indigestible for pigs and poultry such as beta-glucans These compounds however are not a problem for ruminants

Because of its higher fiber content, barley has low energy value than corn

Barley starch is considerably more degradable in the rumen and

may cause digestive disturbances if fed at higher levels, and

the animal has not gradually adapted to the diet

In many countries wheat grain is also regularly fed to dairy cows

Wheat is palatable and has higher protein content than corn and

even barley, around 14%

But it's starch is highly degradable in the rumen and

is depletion usually avoided in diets for dairy cows

When fed, it should make up no more than half of the grain in the ration

Many wheat by products are also used as dairy feeds

Some other cereal grains, such as oats, rye,

or triticale may also be fed to dairy cows as an energy source

Rye and triticale, which is a hybrid of wheat and rye,

are high in protein around 15% but may be susceptible to a fungus,

ergot, which produces a toxin called ergotamine

Oats are palatable feeds with high fiber content,

around 30% nitrogen fiber, and with a low energy value than other grains

Oats can be safely fed to dairy cows when they're available

Last but not least, sorghum grains can be fed today to cows in the US, and

they are also important dairy feed in other countries

There are many sorghum varieties, and

an average chemical composition may be misleading

Sorghum has more protein, around 11 to 12%, but less oil than corn

Darker varieties have higher tannin content which may decrease protein

digestibility

Sorghum has around 90-95% of the energy value or corn grain

It has to be processed because of the small kernels or

otherwise a portion of it will partially digest into feces

Another category of feeds for the cows is protein concentrate feeds

Protein feeds are valued because of ruminal undegradability,

amino acid composition

And last but not least price

Cost of protein feeds should be converted to my unit of protein base and

then the feeding value of the protein should be evaluated based on concentration

of key digestive limiting amino acids such methionine, lysine, and histidine

The most important feed in this category is, soybean meal, which is also the most important protein feed for other farm animals including bison

Soybean meal is essentially a byproduct of soybean processing industry

It's valuing animal nutrition however such that it counts for

50 to 75% of the value of the soybean processing industry

Soybean meal is high protein, typically around 50% crude protein feeds

That can be savory fat to dairy cows as the major protein supplements in the diet Soybean meal protein is of high quality bean almost entirely too protein

There are two types of soybean meals, solvent-extracted and

expellar, named after the processes used to extract the oil from the beans

Solvent-extracted meal has little oil left, around 1 to 2%,

while expellar soybean meal can have up to 8 or 10% residual oil

Extracting oil by expellar creates high temperature which

partially protects the soy bean protein from microbial degradation in the lumen, thus increasing the feeding value of the soybean meal for ruminum animals

In addition to having more valuable protein axpeler,

or extruded soybean meal, has energy value,

down solvent extracted soybean meal because of its high oil content

During the extrusion process the heat creates browning combine with reactions which give specific reddish cower to the excluded meal

Overheating is not desirable because protein digestibility may decrease

There are number or commercial products essentially heat dated soybean meals that are designed to deliver amino acids to the cow post rumen

Similar to cereal grains, oil seeds have lower calcium but higher phosphorus

concentration compared to a typical dairy forages except corn silage

Whole soybeans, raw or heat treated are also commonly fed to dairy cows in the US Oil in raw soybeans may deteriorate over time

because the seed contains lipase enzymes that may hydrolyse the oil and

release free fatty acids that will cause the beans to become rancid

All soy beans can be roasted to 310,

320 degrees farenheit, which is 150, 160 degrees celsius, and

then for the process half to a quarter, but not ground, before being fed

The advantage of roasting soy beans is that the high temperature increases

The lumen bypass protein which is more valuable to the cow

than the rumen degraded protein which soybeans have plenty of

All soybeans also have high energy value because of the oil in them which is 18 to 19% Thus, whole roasted soybeans are an excellent

source of digestible energy and rumen bypass protein for dairy cows

Because of their high unsaturated oil content, whole soybeans should not be fed

to more than 20% of the concentrate portion of the ration

We'll continue discussing protein feeds in our next lecture

>> Hello and welcome back

In this lecture we'll continue our conversation on protein and

byproduct feeds and feed supplements for dairy cows

Canola rapeseed meal is another popular protein feed for dairy cows

Canola is rapeseed that has been bred to be erucic acid and glucosinolates free Canola meal is higher in fiber, around 29, 30% Neutral Detergent Fiber

Low in protein which is around 38%

And is usually slightly higher in oil than soy and extracted soybean meal

An advantage of canola or

rapeseed meal is it's higher methionine content compared with soybean meal

As already discussed, methionine is a key limiting amino acid in dairy diets

Most recent data has shown that dairy cows produce more milk when with fed canola versus soybean meal

Sunflower meal is a byproduct from the sunflower oil industry and

can also be fed to dairy cows

It has higher fiber, 40% Neutral Detergent Fiber depending on the method

of processing, and lower protein around 28% content

And thus, its feeding value is lower than soybean and canola meals

Its protein has higher concentration of methionine but

it is also more degradable in the ruminant

Where available whole cottonseeds or

cottonseed meal can be a valuable protein supplement for dairy cows

Whole cottonseed is also high in digestible fiber,

around 50% Neutral Detergent Fiber, and energy due to its high oil content,

around 90%, and can be fed up to 10% of the ration dry material

The meal, following the oil extraction has around 45% good protein,

but unless it's a gossypol-free variety, may have high levels of gossypol,

which is toxic to farm animals

Meals from other oil seeds or oil plants,

for example flax, safflower, peanuts, coconut, which is a copper meal, or

legume seeds such as peas and beans, can be in the ration of dairy cows

In all cases it is important that we know the chemical and

mineral acid composition, ruminal degradability and presence of any toxic or

anti-nutritional factors in these feeds

Where our regulations do not specifically prohibit it,

animal proteins can be included as a source of amino acids in dairy diets

Typical animal protein feeds are blood, meat, bone, and meat meals,

poultry byproduct meals, feather meal, pork meal, and others

Blood meal can be extremely variable in its quality and attention should be paid

to the source, processing, and nutritional specifications provided by the supplier

If overheated during processing, intestinal digestibility of the amino

acids in blood meal will be drastically decreased

Fish and shrimp meals can also be fed to dairy cows depending on quality,

availability and price

These meals are good sources of amino acids but are usually expensive,

have a short shelf life, are not very palatable, and

in some cases may alter the flavor of milk

Other byproduct feeds include distillers grains from the ethanol industry and

brewer's grains from the brewing industry

Both sources of rumen bypass protein

Various corn and wheat milling byproducts, bakery byproducts, soy,

cotton seed, and almond hulls which are all sources of digestible fiber

Beet and citrus pulp, again, sources of digestible fiber

Sugar beet or cane molasses, palm kernel meal, potato and

rice b-products, animal fat and others

Cows particularly like sweets, and inclusion of molasses in the diet may

have a beneficial effect on feed intake and milk production

Our lecture will not be complete if we don't discuss briefly the most common feed additives used in dairy diets

There is a long list of feed additives on the dairy market

They are all designed to more or less successfully increase milk production,

improve milk composition, for example, increase milk fat and

protein concentration, and/or enhance animal health

An incomplete list of feed additives will include yeast cultures and

probiotics of various kinds

They are designed to enhance rumen fermentation or targeting gut health

Anionic salts for transition cow diets

Various vitamin and vitamin-precursor supplements such as biotin,

beta-carotenes, niacin, non-protein nitrogen sources including

slow-release urea nitrogen products, enzymes

Usually designed to increase digestibility of feed fiber

Antibiotics including ionophores such as monensin and lasalocid,

which are both designed to modify rument fermentation

Propylene glycol, calcium-propionate, rumen-protected choline,

rumen protected amino acids

We should remember that unprotected amino acids will

be destroyed by the bacteria in the rumen

Buffers to stabilize rumen pH such as sodium bicarbonate, magnesium oxide, and others

Essential oils and plant derived bioactive compounds such as saponins and tannins Perhaps the most commonly used feed additive in the dairy industry

are yeast cultures

Yeast are grown in commercial fermenters, processed, and

then included in the diet of dairy cows

Beneficial effects include more stable rumen fermentation, increased feed intake, and increased milk production

Rumen-protected amino acids such as lysine and methionine

are used to provide digestible limiting amino acids to high-producing dairy cows, particularly when the total protein content of the diet is relatively low,

which is about 16 or less percent

Ionophoric antibiotics have a long history of used in the beef industry and

have relatively recently been approved for

use in the dairy industry in the United States

Their main mode of action is to modify rumen fermentation,

making it more efficient, which usually results in increased feed efficiency of

the animal, which means producing more milk with similar or lower feed intake With this variety of feed additives, dairy farmers and

professional nutritionists are often confused how to interpret the benefits,

particularly cost benefits, of using additives in their ration

One thing we have to make clear, no feed additive cannot substitute for

good understanding of animal needs, feed, particularly forage quality,

and basic diet formulation

We have have to mention non-protein nitrogen products,

which are use in ruminal diets as a source of nitrogen for

the rumen bacteria to produce microbial protein

This protein is in turn used by the cow as a source of amino acids

The most common non-protein nitrogen source in cattle diets is urea

Urea is broken down to ammonia in the rumen and the microbe use it,

provided they have sufficient energy for synthesis of their microbial protein

Ammonia, however,

is toxic, and too much urea ingested too quickly can kill the animal

Inclusion levels of urea in dairy diets usually does not exceed 1 to 1.2% of

dietary dry matter

We have to remember, however,

that non-protein nitrogen cannot be a substitute for

high quality rumen degradable protein, such as from soybean or canola meals This is because rumen bacteria grow better on plant protein, amino acids, and peptides than on non protein nitrogen

In our next lecture we will discuss how to make high quality hay and silage

ello, my name is Alex Hristov and

I am professor of Dairy Nutrition at Penn State University

In this lecture we will talk about Hay and Silage-Making

Please also check Dr Roth's lectures on dairy forages from an economic standpoint Before we begin this lecture, I must re-emphasize

the critical importance of forage quality for successful dairy operation

There is nothing more important, from a nutritional viewpoint, for

a successful and profitable dairy farm than the quality of the forages

In many production systems this quality can be controlled by preserving forages

or silage

In pasture based or grazing systems, the quality of the pasture has to be

constantly monitored and managed, for example by rotational grazing,

to use maximum digestible organic matter per acre

Farmers have preserved forages for their cattle for thousands of years

The simple reason for doing this is to provide feed during seasons of the year when fresh forages are not available

Also, as mentioned in our previous lectures, the quality and

nutritive value of forages deteriorates as they mature, therefore,

an all important goal of preserving forages is to harvest them in their

optimal growth stage when they are the most nutritious

How do you preserve forages?

The technology is simple and millenia old

Open your pantry or the refrigerator in your kitchen, and

you are likely to see silage

Well, not exactly the kind of silage we feed to diary cows

But full preserved using the same process we use to make silage

The two main process to preserve forages or dairy and

beef cattle, are hay silage-making

When making hay, we are drying the material, usually in the field,

to a moisture level of about 12 to 18%

First a malt at optimal maturity

The wider the swath, the faster the hay will dry

Then, as the hay starts drying in the sun, and reaches about 40 to 50% moisture,

It is tadded or raked to speed up the drying or curing process

This has to be done at the right time and moisture to speed up curing and

minimize leaf losses as much as possible

Particularly if the forage is alfalfa

Alfalfa leaves have greater concentration of protein and

are more nutritious than the stems, so we don't want to loose too many of them Rain is enemy number one of good quality hay

A rain event while the hay is on the ground

could cause up to 40% loss of plant nutrients

Therefore, farmers are trying to time mowing and curing

of the hay with dry weather and then harvest the dry hay as soon as possible Plant cells continue to respire or burn energy in the form of sugars after mowing

So, if the curing process is prolonged,

losses of valuable nutrients will increase

Harvesting and storage are the last steps in hay making

Hay is usually baled in small or large rectangular or round bales

And could be stored under a shed or

wrapped in plastic for better preservation

Moisture of baling is critical

Usually target moisture is around 12 to 18% which will depend on the type and density of the bales

If the hay is too dry, field losses will be high

If it's too wet, it will spoil upon storage

To avoid this, start baling early in the morning when the dew is on the hay and quit when moisture drops below 11, 12% particularly with alfalfa

Another point that some farmers start considering is the fact that

plants photosynthesize and accumulate non-fiber carbohydrates,

usually sugars, during the day and then burn them at night

Thus hay harvested in the afternoon has higher sugar content and

has been shown to be more palatable to animals than hay harvested in the morning This however has to be reconciled within increased leaf washes

if hay is harvested in the afternoon

Once bailed, hay motion quality need to be monitored so

it can be efficiently included in rations for various categories of dairy cattle

Now let's talk about silage

In many intensive production systems, silage is the most important feed for dairy cows

Just like hay, the idea of making silage is to harvest the forage in its optimal growth stage, preserve its quality as much as possible, or actually even increase it And have feed with relatively constant quality available throughout the year The salt process relies on bacteria producing enough lactic acid to bring

silage acidity, or pH down to levels usually below 5

Which will depend on the type of silage

Once this acidity is achieved, fermentation slows down and

eventually stops and the silage is preserved

There are several important points to remember when making high quality silage First, where are the bacteria producing lactic acid in the silage coming from? Usually they're already on the plant

So, how much beneficial versus harmful bacteria are coming into the silage with the harvesting the forage can determine the type of silage fermentation and

eventually silage quality

The beneficial bacteria are the lactic acid producing ones

These are the same kind of bacteria that ferment sauerkraut, yogurt, or cheese The undesirable bacteria are of various kinds but

some of the most harmful belong to a group called Clostridia

These bacteria are commonly found in soil and

some produce deadly compounds such as tetanus and bodily toxins

To promote beneficial fermentation farmers often use products that contain

lactic acid bacteria and our called silage inoculants

These products are designed to speed up lactic acid accumulation and

some also help preserving silage quality when the silo is open

We'll discuss innocuousy now in next lecture

Another important factor is the type of forage to be ensiled

Some forages are more difficult to ensile than others

The main factors here are the buffering capacity of the plant

Which is the capacity to buffer the lactic acid for used by microbes and

the plants sugar content

Plants with high protein contents such as legumes,

who have high buffer in capacity and are more difficult to ensile than, for

example, grasses or corn and small grain silages

Sugars are needed for the silage material to thrive and convert it into lactic acid This is the end of today's lesson

We'll continue discussing silage quality in our next lecture

Hello and welcome back

We'll continue discussing the factors important for making high quality silage Apart from plant my crops and the type of forage we are [INAUDIBLE],

maturity at harvest, and forage [INAUDIBLE] or

moisture at the [INAUDIBLE] are also very important for silage quality

The more mature the plant at the time of harvest the lower the digestibility and energetic value of the silage

Also more mature plants tend to have lower sugar content

which may slow down silage fermentation and prolong the time to reach optimal pH Dry matter of the forage in siling is perhaps the most important factor in

silage making

The wetter the forage, the higher the fermentation rate, but

also fermentation losses

Silage should not be made from forage that has 25% or less of dry matter

When dry matter is between 30 and 25% or

lower, the use of silage preservatives such as organic acid is advisable

Forages with dry method in siling around 40% can

be preserved well without any preservatives

The higher the dry matter, however,

the more difficult packing the silage becomes, and losses may also increase

For most silages,

the dry matter siling of around 32% to 40% will produce good results

Another critical factor in silage making is packing

It won't be an exaggeration to say that the first rule of silage making is pack,

pack, and pack again

Packing is so important because most undesirable processes that

may take place in silage require oxygen

Lactic acid bacteria, or the good bacteria in silage, on the other hand, hate oxygen

So by packing the silage as much as possible will get rid of the air which

creates unfavorable conditions for harmful bacteria such as custrelia and

favorable conditions for the lactic acid producing bacteria

The speed by which the silage is filled is also important

Ideally a silo should be filled within three to five days

In the real world the goal should be to fill a silo as soon as possible

while continuously packing the material that is already in the silo

Having the right particle size of the forage entering the silo,

is a precondition for successful packing

Recommendations for grass and

alfalfa silages are to harvest at theoretical length of cut of three-eighths

to half inch which is about 1 to 1.3 centimeters and for

corn silage at half to three-quarters inch, which is 1.32 centimeters

The longer the cut and

the dryer the forage, the more difficult packing will be to get the air out

Too short length of cut, however, is not going to provide the necessary effective fiber to the animal, which may result in, and increased milk fat test

Check the supplemental reading for this lecture for

a formula of how to calculate the density of your silage

A good benchmark is 40 pounds

per cubic feet which is about 640 kilograms per cubic meter

Another component of the siling process is silage preservatives

There is a long list of silage preservatives on the market including

acids usually organic, for example, formic and benzoic acids

Enzymes typically intended to digest plant fiber thus providing additional sugars for fuel, silage fermentation, and microbial inoculants

The later categories most widely used and typically contains

homolactic material designed to produce primarily lactic acid

Recently silage inoculants also contained

bacteria called heteroactic that produce volatile fatty acids such as acetic and propionic which help preserve the silage phase when the silo is open

One important thing to remember about inoculants is that the viable microbial count specified on the back label is not always representing accurately

the actual viable count that the inoculant will produce when applied to the silage

As a rule of thumb,

inoculants should be supplying a minimum of 100,000 colony forming units Which is a measure of the number of viable bacteria,

of lactic acid bacteria per gram of wet forage

Another type of silage that deserves mentioning, is urea,

or other non-protein nitrogen sources, such as anhydrous ammonium

These are added usually to corn silage, which has raw protein content, for

two main reasons

First, to serve as a preservative because ammonia inhibits bacteria and

second, to increase the silage protein content

Remember that the rumen microbes can utilize non-protein nitrogen

to synthesize microbial protein

Recommendations are for around eight to ten pounds feed grad urea per ton of wet silage, which is four to five kilograms per metric ton

Even distribution of the urea is important, and

the silage should not be too wet or too dry

Less that 30 or above 40% dry measure

Once the silage is in the silo and is packed well, it must be covered to prevent air penetration, spoilage, and nutrient losses

Some silage systems, such as tower silos, ag bags, or

wrapped bale silage, are protected from the air

Bunkers or other type of open silos, however,

must be covered, usually with plastic sheets

And then the plastic cover should be weighed down, usually with cut in half, old automobile tires, or bags filled with sand and gravel

Separate plastic sheets should overlap and

be taped, particularly around the silo walls

If the silo is a bunker type or the base of the pile if it is a pile silage

The cover should be inspected for leakage and

holes, particularly if in a windy place

Newer plastic material such as oxygen barrier fumes have much lower oxygen permeability than the regular polyethylene and

can reduce significantly silage losses

To properly ferment, silage should be stored for

at least 30 to 45 days before being fed

Silage fermentation may actually increase the energetic value of the original forage, particularly true with corn silage

However, feeding unfermented silage could cause decreased milk production

Once the silo is open air and oxygen acts as the surface as the silage and

undesirable microorganisms such as yeast and molds start to grow

Therefore managing the open silage surface is also very important

in order to insure the high quality of the silage the cow gets

The key is to reduce exposure to air as much as possible

This can be achieved by using various silage cutters, or block

Or simply carefully moving continuous surface layer of the silage

As a rule of thumb, a minimum of 6 inch, or

about 15 cm silage should be removed from the silo surface everyday

And more should be removed in the summer

Remember that any manipulation that leaves a pile of loose silage

will lead to high nutrient losses and poor quality silage

Finally, when we start feeding new silage, we should always analyze it for

chemical composition to be able to more accurately predict it's notative value and properly include it in the ration

What are the most important silage quality analysis we should pay attention to? The first one is silage pH

It should be below four for corn silage and below 4.5 to five for legume silages Another one is lactic acid

For corn and legume silages, the target is around 4 to 7% of the silage dry matter Butyric acid is an indication of clostridia fermentation and

should be very low, below 0.1%

Or completely absent from good quality silage

For legume silages,

which usually undergo extensive which is a breakdown of the plant proteins, ammonia nitrogen should be less than 10% of the total silage nitrogen

Here's an example of a lab report for chemical analysis of alfalfa

The first thing to note is that the analysis was done by NIR or

near-infrared reflectance spectroscopy

NIR analyses are considerably less expensive than wet chemistry, and

commercial laboratories have accumulated large spectral databases for common feeds which is an important prerequisite for accuracy of this analysis

Following the sample identification data, the first line in this report

shows dry matter content of the haylage, which is 46.2%

Consequent analyses are usually interpreted on a dry matter basis

Protein bases, as in the case with protein fractions

This particular lab here structured the report into several categories,

including proteins, fiber, carbohydrates,

minerals, qualitative analysis, and energy and index calculations

Some important analysis in the proteins category include crude proteins,

soluble protein, ammonia NAEF and

NDF protein both being proteins bound to fiber

Rumen Degraded Protein is also an important indicator for legume forages and

is 83% of the total protein in this stage

In the fiber category we find a couple different values for

neutral [INAUDIBLE] fiber

The a in front of NDF means that the sample was treated with amalyse

enzyme to remove starch

And the OM after NDF means that NDF is expressed on an organic meta basis

In the carbohydrates category, it is worth noting the high soluble fiber value, which can be calculated at around 38% of the neutral detergent fiber

In this sample and represents pectins and other soluble polysaccharides

Concentration of total ash and

important minerals are listed under the minerals category

Note the high calcium and potassium content of this which is typical for

legume forages

pH and silage acids are listed on the qualitative analysis

Silage pH is below five,

which is an indication of good [INAUDIBLE] fermentation

And lactic acid is above 4% of the dry matter,

which is within the goal of 4 to 7% for legume forages

Being at the lower range is a reflection of the relatively high parameter content

of this scalage

Note that this lab here stated that the NIR analysis is an excellent prediction potential, which means that they have accumulated a large database for

alfalfa hayage and are confident in their prediction equations

In the energy and index calculations we find calculated total digestible nutrients

or TDN and energy values for this haylage and other estimated foliage

characteristics such as relative feeding value and non fiber carbohydrates Overall, this slap analysis report indicates that our haylage is of a good

quality and reemphasizes the importance of knowing forage composition before attempting to include it in rations for dairy cows

This is the end of today's lecture, next we will discuss feed processing

Hello, my name is Alex Hristov, and

I am Professor of Dairy Nutrition at Penn State University

This lecture will talk about feed processing and

its importance in feeding dairy cows

So why are we discussing processing of feeds?

The answer to this question is simple

Because we want the cow to get as much energy and

other nutrients out of the feed we offer to her as possible

It is important to remember that by processing,

most of the time we increase the energy value of feeds

Other reasons for processing include improved palatability,

the reduced feed losses and better feed preservation

With forages, we reduce the particle size by chopping the plant material so the microbes in the rumen can access the digestible nutrients

Microbial digestion cannot take place unless the microbes attach to the plant particles

They have to literally colonize the plant fragment to start the digestion process

In nature, the cow will have to chew the roughage she consumes to

allow access of the rumen microbes to the plant tissues

We help ruminants by doing some of the work by chopping forages for them

They still chew their cud, which is very important for

producing enough saliva to buffer the rumen, but

processing decreases the energy expended for particle size reduction

Keep in mind that a healthy cow with a normal dairy diet produces around

25 to 50 gallons, or 98 to 190 liters, of saliva everyday

Particle size is very important for proper rumen function

Penn State has produced the particle separator that is a simple device with

several sieves allowing evaluation of feed particle size

The forage or ration sample is shaken for several minutes and

then the proportion of particles left on each sieve is weighed

This table shows recommended particle size distribution for

a dairy total mixed ration and corn silage and alfalfa haylage samples

Briefly, the top sieve will retain particles that are larger than 0.75 inch

or 19 millimeters, and are likely to promote chewing and salivation

As particle size decreases from larger than 19 millimeters

to smaller than 4 millimeters, which is around 0.16 inch,

their chance to leave the rumen increases and

their function in promoting saliva production decreases

Particle size distribution guidelines for corn silage, alfalfa silage, and

total mix ration and instructions how to use the Penn State particle separator can

be found in the additional readings for this lecture

Wet or dry forages should be chopped to promote microbial colonization and

digestion

The particle size guidelines outlined above and

in the earlier silage lecture should be followed

It is important then the forage is not chopped too fine, because this will lead

to lack of effective fiber in the diet and may contribute to rumen acidosis

Dr Dave Mertons from the Dairy Forage Center in Madison,

Wisconsin, defined effective fiber, or eNDF,

as the overall effectiveness of the neutral detergent fiber in the diet for

maintaining milk fat test, and physically effective fiber, or

peNDF, as the specific effectiveness of neutral detergent fiber for

stimulating chewing activity

Mertons calculated, for example, that physical effective fiber of soybean hulls, brewers grains, corn silage, legume silage fine chopped or

legume silage coarse chopped, legume hay, and grass hay were 3%, 18%,

There are other treatments that can be applied to low-quality

roughages such as straw or corn stover

These include treating the forage with alkali, anhydrous ammonia, or urea

These treatments are intended to partially break down bonds between digestible fiber

and indigestible lignin, thus increasing the overall digestibility of the feed

Additional benefit with ammonia or

urea, which will release ammonia when hydrolyzed during the treatment process,

is that the crude protein content of the forage will also increase

This can be particularly beneficial with low-quality hays,

straw, corn stover or other high-fiber by-products

The effect of anhydrous ammonia can be substantially enhanced if ammonia

is used under pressure and increased temperature

Installations such as the one shown here combine liquid ammonia, pressure, and high temperature to achieve up to 15% increase in wheat or barley straw digestibility Anhydrous ammonia can also be injected into bales covered with plastic,

as shown in this picture

Next we will talk about processing grain

If not chewed by the cow or somehow processed before being fed,

grain kernels can remain indigested in the rumen for

a long time due to the protective function of their seed coat or the pericarp

Therefore, to facilitate digestion,

the seed coat of the grain kernel has to be at least damaged so

the microbes can penetrate and digest nutrients within the kernel

For some grains that are less digestible, such as corn, for example, the extent of processing is directly proportional to the extent and rate of digestion in the rumen The effect of processing on digestibility of grains such as barley and

wheat is small due to their inherently higher starch and

protein digestibility than that of corn and sorghum

This means we can, to some extent, regulate digestion rate of grain,

particularly starch, by processing

For example, if we would like to have a more rapid rate of corn starch digestion,

we would use a more aggressive processing such as fine grinding,

steam rolling, or steam flaking

If our diet already contains a lot of digestible carbohydrates and we would like

to minimize corn starch digestion rate but still not lose starch in manure, we would use a less extensive processing method such as coarse grinding for example

We have to always keep in mind that fine-grinding

grain will increase its digestibility for dairy cows but,

depending on the overall diet, may also increase the risk of acidosis

There are two types of grain processing, physical and thermal, or heating

Physical processing is used to break the seed coat and

allow microbial access in digestion

This kind of processing may also increase palatability of the grain

Usually the advantage of physical processing is with small,

hard grains and for grains with thick seed coat

Thermal processing involves temperature and usually also moisture

Starch is heated, grain swells and gelatinizes

The advantage of thermal processing is with less fermentable grains such as corn and sorghum

There are also other methods of processing such as roasting,

pelleting, extrusion, and micronization

Thermal processing called heating usually involves steam

The time of exposure to heat or

steam will determine the extent of starch gelatinization and its digestibility

Steam-rolling, for example, exposes the grain to steam for

up to around eight minutes, and starch gelatinization is kept to a minimum

With steam-flaking, on the other hand, grain is exposed to steam

up to 30 minutes and starch is gelatinized to a much greater extent

Then the grain is rolled into flakes of varying thickness, which is also called

test weight, depending on the type of animal it's going to be fed to

Gelatinization is proportionally related to digestibility because

the combination of moisture and

heat break down the intermolecular bounds of the starch molecules

The starch granules absorb water, swell, and then burst, releasing starch

Steam-flaking is perhaps the most extreme process of grain

that has the greatest effect on starch digestibility

The decision to use one grain processing method over another,

however, has to be also based on cost of processing

Processes such as steam-flaking are more expensive and

may not be justified under some conditions

For example, with grains such as barley, or

when the diet already contains high levels of digestible starch or

corn silage with high proportion of grain harvested with a kernel processor

Tempering is another grain processing method consisting of adding water to

the grain and allowing to soak for up to 24 hours

This causes some swelling of the starch and increases digestibility

In some cases a tempering agent is added

These are surfactants, usually saponin-containing products,

which facilitates water penetration into the kernel

The grain can then be rolled to different thickness depending on whether

it's going to be fed to beef or dairy cattle

In our previous lectures, we discussed roasting of whole soybeans and

extruded soybean meal

Both products are good sources of rumen bypass or rumen-undegraded protein, and also provide extra energy as fat to the cow

On this last point, the two feeds are quite different

Whole soybeans have up to 19% fat and extruded soybean meal up to 10% fat More importantly, whole soybeans are less likely to affect fermentation in the rumen because fat is released at a slower rate than fat from extruded soybean meal

You may remember that unsaturated fatty acids such as those found in soybean and other vegetable oils are more detrimental to the rumen microbes

than saturated fatty acids predominant in animal fat

Whole soybeans are usually roasted to around 270,

320 degrees Fahrenheit, which is 130 to 160 degrees Celsius

This is intended internal grain temperature,

and then further processed before being fed

Fine grinding will increase protein degradability and

is therefore not recommended for roasted soybeans

It is usually recommended that they are coarsely processed to halves and quarters There are different systems used to roast beans, such as drum roasters,

high-temperature air dryers, or open-flame roasters

Independently of the process, temperature and heating and steeping time have to be monitored to achieve desirable rumen bypass protein levels, but

also not overheat the beans

The later may cause formation of indigestible [INAUDIBLE] products,

which will decrease intestinal digestibility of the soybean proteins

Roasted corn or other grains such as barley and

wheat can also be fed to dairy cows

Heating of the starch increases gelatinization and digestibility

Roasting also produces caramelization of the sugars in the grain,

which enhances palatability and may increase feed intake

Last we will briefly discuss extruded soybean meal

A number of commercial extruded,

expeller soybean meal products are available on the market in the US

The processes used to produce these meals vary, but

are generally based on the principle of pressing the beans with a screw press

which partially extracts the oil and creates heat by friction

In the extrusion process, beans are first preheated in a dryer,

which prepares them for the higher temperature of the extruder

This higher temperature cannot be reached if the beans are not preheated,

then moved to a receiver, and

finally pressed through a discharging die by high roast screw in the extruder

Temperature is usually around 300, 320 degrees Fahrenheit, or 150 to 160 degrees Celsius, and is regulated by adjusting the pressure through the die,

which increases or decreases the friction and the temperature of the extruded beans This is the end of today's lecture

In our next several lectures, we'll discuss specifics of feeding lactating

cows at the various stages of their lactation cycle

All of the above

It's high starch degradablility

It's low protein content

It's high fiber content

It's low calcium content

Mostly degradable in the rumen

Mostly undegradable in the rumen

Mostly true protein

Mostly non-protein nitrogen

High leaf losses

Losses due to heating

High fermentation losses

All of the above

Gelatinization of starch during processing of grain is facilitated by: