By: A. Riasi (PhD in Animal Nutrition and Physiology) Http://riasi.iut.ac.ir Isfahan University of Technology Advance Digestive Physiology (part 3)

By: A. Riasi (PhD in Animal Nutrition and Physiology)

Http://riasi.iut.ac.ir

Isfahan University of Technology

Advance Advance Digestive Digestive

PhysiologyPhysiology(part 3)(part 3)

• At birth day the rumen is sterile

• Aerobic bacteria

• Change of bacteria population

Establishment of bacteria in the rumen

• Effect of prolonged milk feeding

• Typical ruminal microflora

• Establishment of protozoa


Factors may affect calf’s rumen microflora

◦Feeds

◦Environment

◦Bedding

◦Hair


The numbers of total bacteria

The types of bacteria


Establishing a rumen microflora


Milk does not help rumen development at all

Water is essential for rumen development

Liquids in the rumen

Measures of ruminal activity include:

◦Rumen contractions

◦Rumen pressure

◦Regurgitation (cud chewing).

Little muscular activity at birth.

Outflow of material from the rumen

With increasing intake of dry feed, rumen

contractions begin.

Solid feed intake stimulates rumen microbial

proliferation and production of microbial end

products


The chemical composition of concentrates

causes:

◦A shift in the microbial population

◦Increasing butyrate and propionate production at

the expense of acetate.


Forages, have an increased ability to maintain

a higher ruminal pH, due to:

◦A larger particle size

◦An increased fiber content


Concentrates appear to result in greater

rumen epithelial development than forages.

The forages is not helpful in the early stage

of rumen development.


The rumen wall consists of two layers:

◦The epithelial

◦The muscular

Absorptive ability of the rumen tissue

The end-products of fermentation.

Butyrate and propionate most readily

absorbed by rumen epithelium.

Absorptive ability of the rumen tissue

The primary factor determining ruminal

development is dry feed intake.

◦Starter

◦Proper stimulation for rumen development

Availability of substrate

Parakeratosis have some adverse effects:

◦Creating a physical barrier.

◦Restricting absorptive surface area and volatile

fatty acid absorption.

◦Reducing epithelial blood flow and rumen

motility

◦Causing papillae degeneration and sloughing in

extreme cases.

Rumen parakeratosis

Initial evidence of parakeratosis is papillae

clumping and branching.

◦Followed by papillae degeneration and

sloughing.

Rumen parakeratosis

Concentrate diets:

◦Increased volatile fatty acid production

◦Decreased rumen buffering capacity

◦Subsequently decreased rumen pH

Rumen parakeratosis

Increased feed particle size:

◦Maintains epithelial and papillae integrity and

absorptive ability.

◦Increased rumination and rumen motility

◦Increased salivary flow and buffering capacity

◦Development of mature rumen function and

environment.

Rumen parakeratosis

Feed physical structure:

◦Development of rumen muscularization

◦Development of rumen volume

◦Stimulation of rumen motility

Changes in rumen muscularization

Understanding the cellular biology and

physiological changes of rumen development:

◦ Neonatal calf digestion kinetics

◦ Development of low-impact or non-invasive research

procedures could be instrumental in advancing this area

further.


While much is known related to rumen

development, several areas require

additional study.


Bloat can affect either:

◦Abomasum

◦Rumen

Abomasal bloat is often rapidly progressive

and life threatening.

Bloat in young ruminant animals

Factors contributing to abomasal bloat:

◦Overfeeding milk

◦Feeding milk too fast

◦Pathogens, such as Clostridium


Clostridium perfringens types A, B, C

Clostridia are normally found in the intestine

of cattle and can survive for months in the

soil.


Overeating or abrupt diet changes tend to:

◦Produce indigestion that slows gut movement

◦Providing the sugars, proteins and lack of oxygen

needed for rapid growth of Clostridia

◦Wet conditions also seem to favor this organism


Affected calves may:

◦Stop eating

◦Show uneasiness

◦Kick at their abdomen

◦Calves are often found dead


The other factors:

◦Impaction of the abomasum or intestines with

non-feed substances such as bedding or hairballs

◦Structural or physiological problems with the

abomasum


When milk persistently flows into the rumen,

calves may show of symptoms including:

◦Unthriftness and growth retardation

◦Poor appetite and abdominal distention

◦Recurrent bloat

◦Hard feces

◦A long dry hair coat


Management practices to consider include: ◦Colostrum management◦Feeding time◦Milk temperature◦Feeding equipment◦Antibiotics◦Feed ingredients◦Stress◦Health status


Documents

By: A. Riasi (PhD in Animal Nutrition and Physiology) Http://riasi.iut.ac.ir Isfahan University of Technology Advance Digestive Physiology (part 3)