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
