Transcript Proteins in Nutrition

Isfahan University of Technology
Advance
Digestive Physiology
(part 3)
By: A. Riasi
(PhD in Animal Nutrition and Physiology)
Http://riasi.iut.ac.ir
Establishment of bacteria in the rumen
• 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
Establishment of bacteria in the rumen
 Factors may affect calf’s rumen microflora
◦ Feeds
◦ Environment
◦ Bedding
◦ Hair
Establishment of bacteria in the rumen
 The numbers of total bacteria
 The types of bacteria
Establishing a rumen microflora
Establishment of bacteria in the rumen
Liquids in the rumen
 Milk does not help rumen development at all
 Water is essential for rumen development
Outflow of material from 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
Outflow of material from the rumen
 The chemical composition of concentrates
causes:
◦ A shift in the microbial population
◦ Increasing butyrate and propionate production at
the expense of acetate.
Outflow of material from the rumen
 Forages, have an increased ability to maintain
a higher ruminal pH, due to:
◦ A larger particle size
◦ An increased fiber content
Outflow of material from the rumen
 Concentrates appear to result in greater
rumen epithelial development than forages.
 The forages is not helpful in the early stage
of rumen development.
Absorptive ability of the rumen tissue
 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
absorbed by rumen epithelium.
most
readily
Availability of substrate
 The primary factor determining ruminal
development is dry feed intake.
◦ Starter
◦ Proper stimulation for rumen development
Rumen parakeratosis
 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
sloughing.
by
papillae
degeneration
and
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.
Changes in rumen muscularization
 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.
Changes in rumen muscularization
 While much is known related to rumen
development,
additional study.
several
areas
require
Bloat in young ruminant animals
 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
Bloat in young ruminant animals
 Clostridium perfringens types A, B, C
 Clostridia are normally found in the intestine
of cattle and can survive for months in the
soil.
Bloat in young ruminant animals
 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
Bloat in young ruminant animals
 Affected calves may:
◦ Stop eating
◦ Show uneasiness
◦ Kick at their abdomen
◦ Calves are often found dead
Bloat in young ruminant animals
 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
Bloat in young ruminant animals
 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
Bloat in young ruminant animals
 Management practices to consider include:
◦
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Colostrum management
Feeding time
Milk temperature
Feeding equipment
Antibiotics
Feed ingredients
Stress
Health status