Processing of Feeds

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Do curso por The Pennsylvania State University

Dairy Production and Management

378 classificações

The Pennsylvania State University

Dairy Production and Management

378 classificações

With the world's first MOOOOO-C, you will gain a broad and comprehensive understanding of all aspects of dairy management such as genetics, nutrition, reproduction, animal health, farm economics, and sustainability of dairy production systems. There's something here for everyone whether you are just looking for the basics or have years of experience in the dairy industry. This is an eight-week course. Each week consists of four to nine video lectures, additional reading materials, and a multiple-choice questions quiz. Estimated study time is between three and five hours per week. Learners have the option to purchase a Course Certificate for 49.00 USD. The certificate can be purchased at any time, but you must verify your identify before taking the course quizzes in order to be eligible. For those who cannot afford the certificate fee, financial aid is available through Coursera. Why is producing milk efficiently and sustainably so important? Milk provides humans with over 16 essential nutrients, such as: Energy, Protein and Essential Amino acids, Vitamin A, Vitamin D, several B vitamins, including B12, Pantothenic and Folic acids, and essential minerals such as Calcium, Magnesium, Phosphorus, Potassium, Zinc, as well as other minerals. Did you know that one glass of milk provides a 5-year old child with 21% of his/her daily protein requirements and 8% of their energy needs? Most milk in the world, about 85%, is produced from cattle. However, water buffaloes, goats, sheep, and camel are also dairy animals. The United States, India, the European Union, Brazil, and New Zealand are among the largest dairy producers in the world. Yet among these dairy-producing countries there are varied methods to generate milk with highly variable productivity and efficiency. Dairy production is vital for the survival of billions of people. Globally, around 150 million small-scale dairy households, equivalent to 750 million people, are engaged in milk production. The number and size of dairy farms varies among countries, but in India alone, there are estimated 78 million dairy farms! In the United States, one of the leading milk-producing countries in the world, total milk production has been steadily increasing in the last decades, reaching over 205 billion pounds (93 billion kilograms) in 2014. This was accompanied by a steady increase in average milk yield per cow, reaching 22,260 lb (over 10,100 kg) per lactation in 2014. How has this efficiency been achieved? What methods are necessary to ensure production of high quality milk? How do we balance milk production efficiency with animal health and environmental protection? This course will provide the student with information to better understand dairy production systems and their role in feeding the world population. In this MOOOOO-C, you will learn about the dairy enterprise from internationally recognized dairy science professors who have delivered highly regarded dairy education programs within the United States and internationally. Course lectures are translated into Portuguese and Chinese; PDF files of these translations can be found under each course week. The Dairy MOOC team thanks Dr. Antonio Branco (Universidade Estadual de Maringá, Brazil) and Ms. Yuanyuan Zhang (Pennsylvania State University) for translating the lecture materials. Course Sponsors This course was supported by the generous contributions of Innovation Center for US Dairy at Silver Level and Pancosma North America, RP Nutrients, Inc. and Arm and Hammer, which provided funding support at a Bronze Level. The Pennsylvania State University has final responsibility for the academic content of this course.

Na lição

Feeds, Hay and Silage Making, and Feed Processing

This week you will learn about feeds commonly fed to dairy cows and feed processing. We will first discuss the feeding characteristics of forages such as corn silage, alfalfa haylage, grass and small grain silages, will then move to concentrate feeds that provide energy or protein in a dairy ration, and at the end will discuss feed additives. You will also learn about the most important factors in making high quality hay and silage for dairy cows. The final lecture of this week will introduce you to processing methods designed to increase the nutritive value of forages, the importance of particle size and effective fiber in dairy rations, and most common processing methods for cereal grains and oilseeds. At the end, we will discuss how to read and understand forage analysis reports. Those of you, who would like to get more engaged in discussions and are interested in completing the Course Certificate requirements, can participate in discussion forums and take the weekly quiz. Enjoy this week's material and the entire course!

Dairy Feeds, Part 18:27

Dairy Feeds, Part 27:31

Dairy Feeds, Part 37:47

Hay and Silage, Part 17:02

Hay and Silage, Part 211:38

Processing of Feeds13:02

Conheça os instrutores

Alexander N. Hristov
Professor of Dairy Nutrition
Animal Science
Troy L. Ott
Professor of Reproductive Biology and Associate Director
Huck Institutes of the Life Sciences
Bhushan Jayarao
Resident Director
Penn State Animal Diagnostic Laboratory (ADL)
Greg Roth
Professor of Agronomy
Plant Science
Gabriella A. Varga
Distinguished Professor of Animal Science
Dairy and Animal Science
Chad Dechow
Associate Professor of Dairy Cattle Genetics
College of Agricultural Sciences
Robert Van Saun
Professor of Veterinary Science and Extension Veterinarian
Department of Veterinary and Biomedical Sciences
Kathy Soder
Research Animal Scientist
USDA-Agricultural Research Service, Pasture Systems and Watershed Management
James Dunn
Professor of Agricultural Economics
Agriicultural Economics, Sociology and Education
Lisa A. Holden
Associate Professor of Dairy Science
Animal Science

[MUSIC]

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%,

81%, 67%, 82%, 92%, and 98%, respectively.

What is important to remember here is that by-product feeds, such as soy hulls,

for example, may have high fiber content, 60% neutral detergent fiber.

But their effective fiber will be very low, only 3% compared with over 90% for

hay, because of their low ability to promote chewing and saliva production.

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.

[MUSIC]

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