By: A. Riasi (PhD in Animal Nutrition and Physiology) Isfahan University of Technology Advance Digestive Physiology (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 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 Establishment of bacteria in the rumen

Establishing a rumen microflora

Establishment of bacteria in the rumen

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 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. Outflow of material from the rumen

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. Changes in rumen muscularization

While much is known related to rumen development, several areas require additional study. Changes in rumen muscularization

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: ◦ Colostrum management ◦ Feeding time ◦ Milk temperature ◦ Feeding equipment ◦ Antibiotics ◦ Feed ingredients ◦ Stress ◦ Health status Bloat in young ruminant animals