Ruminant Nutrition Exam 1

4 parts of abomasum

-cardia -fundus -corpus -pyloric region

regions of SI in order

-duodenum -jejunum -ileum

when does growth of the GI tract begin

-early stages of embryonic development

Enteric villi and crypts form structures similar to the gastric pits. what are the cells seen from top to bottom

-enterocyte -goblet cell -enteric endocrine cell -stem undifferentiated cell -paneth cell -enteric endocrine cells, stem cells and paneth cell are in the crypts of lieberkuhn

The rumen wall is divided into what 3 layers

-epithelium (4 layers) -muscle layer -serous layer

describe pillars in the rumen

-highly muscled areas that form grooves on the outside of the rumen -contains blood vessels, lymphs and nerves -fxn: -contractions and compartmentalize the rumen

what are 4 primary functions of rumen

-holding vat for fermentation -alllows for delayed passage (allows time for microbial attachment and fermentation -microbial fermentation -absorption of fermentation products (VFA and NH3) -capacity (most cattle only use ~60-70% capacity

primary stomach of the embryo is called

-stomach primordia

what are the 4 layers of the epithelium layer of the rumen wall

-stratum corneum -stratum granulosm -stratum spinosum -stratum basale

what are the four types of cells in gastric pits

-surface mucus cells -mucus neck cells -parietal cells -chief cells

how many of each kind of teeth do cattle have

32 total -8 incisors -12 premolars -12 molars

what age would you consider an animal an adult ruminant

8+ weeks! -rumen reaches adult proportions as a percentage of body weight

function of pharynx

assist in passage of food, air and liquids and directs to correct location

what is the name for hardware disease? describe the disease

bovine traumatic reticuloperitonitus -hardware punctures rumen wall causing leakage and results in inflammation and contamination in peritoneum

how is the rumen and reticulum separated

by the ruminoreticular fold basically all one compartment, also referred to as the reticulorumen

define the cow taxonomy

kingdom- animalia phylum- chrdata class- mamalia order- artiodactyla family- bovidea genus- bos species- taurus

3 general functions of saliva

large roles in: -buffering -bolus formation -nutrient recycling

what is the mouth comprised of

lips, oral cavity and teeth

functions of the nonglandular compartments of the stomach (reticulum, rumen, omasum)

delay passage of food, fermentation and absorption of fermentation products (slow process)

how are cell types different between the duodenum, jejunum and ileum

duodenum- large amounts of brunners glands (mucus), and has ducts from accessory organs like the pancreas and galbladder jejunum- longer than duodenum, longest villi for increased absorption as chyme moves, has many large circular folds in submucosa called plicae or kerkring folds ileum- last section of small intestine, contains peyers patches or lymphatic tissue used to destroy foreign particles and M cells transport antigens

most abundant cell type in small intestine

enterocyte, columnar epithelial -found in villus epithelium

function of glandular/secretory abomasum

enzymatic digestion of proteins and breaking down foods to liquid forms

which ruminant type evolved later, based on availability of grasses? what do they select for?

grass/roughage eaters - less selective and consume large amounts of lowly digestible plants

parakaratosis of papillae

hardening/keratinization of papillae -occurs when papillae are enlarged and hardened -papillae can clump together -limits absorption -increases opportunity for metabolic disorders

when did both grasslands and grazers appear? what did this cause?

miocene period - grasslands appeared as the earths climate cooled and semi-arid zones developed. -this favored a diverse group of plants -animals adjusted feeding behavior based on forage availability -overtime anatomical variations developed that now allow classification of ruminants into different feeding types

fxn of stem cells in crypt epithelium

most abundant cells in the crypts -proliferate -precursors for enterocyte and other intestinal epithelialcells

What stimulates papillae growth in weanlings

solid food (milk does not!) -mechanical stimulation -*VFAS! (more important than mechanical!)

what does the hepatic artery supply

supplies the cranial surface, pancreas, liver and galbladder

what does the left ruminal artery

supplies the left rumen, reticulum, and esophagus

what is the function of the reticulum

trap foreign particles and serve as a gateway to the rumen

are the papillae vascular?

yes! very vascular with capillary network

what other factors affect rumen papillae

- season (wet vs. dry) - forage quality - animal age - land state (drought vs. wet)

what age would you consider a young-ruminant a non-ruminant

-0-3 weeks

list the VFAs in order from most stimulatory to least stimulatory in the growth and developent of rumen wall and papillae

-butyrate -propionate -acetate

fxn of spiral colon

-absorption of electrolytes and water -break down slowly digested feed residues

describe folds of rumen

-areas of tissue dividing the reticulum and rumen into different compartments -fxn: -mixing and particle sorting -prevent fluid from reaching the cardia during eructation

what 4 cell types are found in the crypt epithelium of the large intestin

-colonocytes (absorb na, cl, vfas and water): L.I. version of enterocytes!! -goblet cells (mucus secretion) -enteric endocine cells -stem cells (proliferate, thus precursors for the colonocyte)

at 6 weeks, what happens to the fetal stomach

-compartmentalized!! -all compartments present -rumen and reticulum develop from dorsal curve -omasum develops from cranial curve -abomasum develops from caudal curve

what are three types of ruminants and what are examples of each? what are their feeding periods like?

-concentrate selectors - roe deer and moose (more frequent eating) -intermediate types - ibex, red deer, goat (not as frequent) -grass and roughage eaters - sheep, cattle (least frequent eaters)

fxn of paneth cells

-contain lysozomes and immunoglobulins -provide host defense against microbes -similar to neutrophils

how does the development of GIT depend on diet

-diet access/vegetation access - vegetation consumption promotes development of forestomach size and function -milk availability - rate of forestomach development depends on milk consumption; high producing mothers, and high milk consumption limits the growth of the GIT tract

where is the blood flow/vasculature found in villi of the small intestine

-lamina propria

describe variations between concentrate and roughage eaters in the rumino-reticulum, stomach and intestines

-grazers have narrower opening between reticulum and rumen than concentrate selectors -grazers have larger rumen and use more of the capacity than concentrate selectors -rumen papillae more evenly distributed in concentrate selectors -smaller omasum in concentrate selectors -smaller intestines in concentrate selectors

describe the structures found in small intestine from largest to smallest

-kerkring folds -villi -microvilli -glycocalyx

how does length of intestines change with fiber digestion

-length of intestines increase with the animals ability to digest fiber

what are the primary organs of the GIT

-mouth -pharynx -esophagus -stomach -SI -LI -accessory organs (liver, galbladder, pancreas)

3 parts of pharynx

-nasopharynx -oropharynx -hypopharynx

large intestine contains:

-no villi (not as good as small intestine) -lack of digestive enzymes -microbial fermentation and VFA production, minimal compared to rumen

what happens to the fetal stomach at 10 weeks

-omasal laminae develop

fxns of clycocalyx or "fuzzy coat"

-protection of epithelium -absorption and digestion -physical structure

what happens to the fetal stomach at 12 weeks

-reticular honeycomb develops

what are the sacs of the rumen

-reticulum -cranial sac -ventral sac -dorsal sac (and gas cap)

in order from most growth to least growth from birth to adulthood, list GIT organs in terms of growth

-rumen -reticulum -omasum -cecum -large intestine and rectum -small intestine -abomasum -esophagus -this indicates that the abomasum and esophagus (and SI) are closer to their mature size, even at birth

what happens to the fetal stomach at 9 weeks

-rumen sac and pillars develop -reticulum and omasum are established

fxn of parietal cells

-secrete HCl (denature proteins)

what is the fxn of the pancreas

-secrete buffer -secrete lipase -secrete amylase -secrete proteases

functions of surface mucus cells

-secrete mucin -secrete HCO3

fxn of chief cells

-secrete pepsinogen -secrete rennin

functions of the mouth

-selecting, -holding, -chewing and -mixing food with saliva (lubrication and enzymes) to form food bolus for swallowing -house salivary glands

what are 5 functions of the omasum

-slow down food passage -pump food to abomasum -absorb water (30-60% of water that enters) -absorb VFAs -absorb electrolytes

what are the 4 blood supplies of the rumen

1- common hepatic artery 2- right ruminal artery 3- left ruminal artery 4- left gastric artery

what are the two major portions of the large intestine

1-cecum 2-spiral colon

after epithelium, what are the 2 types of muscles in the rumen wall

1-deep 2-superficial (aid in contractions muscle layers are crosshatched for maximal gut motility

what are 2 main structures within the reticulorumen

1-folds 2-pillars

what 2 factors control papillary growth?

1-mechanical stimulation (scratch factor from roughage) 2-chemical stimulation - butyric and propionic acid increase blood flow, stimulating mucosal mitosis and cell proliferation these factors control the distribution, size and number of papillae closely related to feeding habits, availability, and digestibility

five layers of the abomasum

1-mucosa 2-muscularis mucosa 3-submucosa 4-muscularis externa 5-serosa -(3 layers of muscle for contractions)

what four veins have venous drainage form the rumen

1-right ruminal 2-left ruminal 3-omaso-abomasal 4-reticular all feed into the hepatic portal vein which feeds directly to the liver (takes nutrients away from rumen, liver gets first pick of nutrients, distributes and detoxifies )

range of rumen osmolarities

260-340 -greater than 350 will inhibit starch and fiber digestion

what age would you consider young-ruminant in the transitional phase

3-8 weeks

normal pH of rumen

5.5-7.2

At what age do calves establish a normal population and fully functional population of microbes within the rumen

9-13 weeks!

lenght of small intestine

about 135 feet

fxn of cecum

beginning of large intestine, -blind sc -breakdown slowly digested feed residues

Describe the reticular groove

begins at end of esophagus and directs milk to bypass the reticulorumen and avoid fermentation when closed -initiated by suckling, -increases nutrient efficiency -gets nutrients to the animal faster, by bypassing slow process in rumen

where is the cranial pillar

between cranial sac and ventral sac

where is the caudal pillar

between the ventral and dorsal sac

what are 2 sphincters of the abomasum

cardiac sphincter pyloric sphincter -regulators of movement

Which were the first ruminants to evolve and evolved before grasses developed? What do they select for?

concentrate selectors - select plants or plant parts rich in easily digestable plant cell contents

describe variations in muzzle, lips, tongue mouth and salivary glands between concentrate selectors and roughage eaters

concentrate selectors: -narrow muzzle -flexible lips -more pointed tongue -wider mouth opening -greater number of salivary glands (0.3% of BW) roughage eaters: -wider muzzle -short lips -plump, piston like tongue -small mouth opening -greater masticatory muscles -lower number of salivary glands (0.05% of BW)

describe differences in feeding behavior of concentrate selectors and roughage eaters

concentrate selectors: -consume highly selected diet -frequent but short bouts of eating (small meals) -consistent fermentation (minimizes acid peaks) -intensive initial chewing with short periods of rumination -fast passage rate of digesta roughage eaters: -not selective -graze over long periods of time (big meals) -brief initial chewing with long periods of rumination -slow passage rate of digesta -greater rumen stratification -low fermentation rate on roughage

Define ruminant

even toed ungulate mammal that chews cud regurgitated from its rumen. the ruminants comprise the cattle, sheep, atelopes, deer, giraffes and their relatives

describe secretions of salivary glands

excrete serous, mucous and mixed secretions containing -electrolytes for homeostasis -bicarb for a buffer -mucins for lubrication and PROTECTION -lipase for enzymatic activity -urea (recycled for ruminal absorption

what is the purpose of kerkring folds, villi, and microvilli

increase surface area

which ruminant type can adapt to one or the other extreme based on food availability?

intermediate feeders

where are the largest/longest/most papillae found in the rumen

on the bottom, in the liquid, not in the top/gas cap

measure of solute concentration

osmolarity

concentration of hydrogen ions

pH

function of esophagus

passage of food bolus, conduit from mouth to stomach -extend from pharynx to stomach -prominent folds permit dilation for swallowing food -works with peristolysis with strong smooth muscle -consists of caudal and cranial sphincter

what happens to the fetal stomach at 8 weeks

reticular groove/esophageal groove develops

what happens to the fetal stomach at 5 months

ruminal papillae develop with vasculatrure

fxn of enteric endocrine cells

secrete CCK from I-cells secrete secretin from S-cells

mucus neck cells fxn

secrete mucus

what is the fxn of the gallbladder

secretes bile

at 4 weeks, what kind of stomach does the fetus have?

simple

fxn of secretin

stimulate bicarb secretion

fxn of cck

stimulate digestive secretions stimulates emptying of the gallbladder

what does the left gastric artery supply

the omasum and abomasum

what does the right ruminal artery supply

the right rumen and pancreas

nerves that innervate the rumen

vagus and sympathetic nerves

fxn of goblet cells in villus vs crypt epithelium

villus: mucus secretion crypt: mucus and protect epithelium of small intestine