Exam 6 Flashcards
What organs does the liver receive portal blood from?
S
S
SI
LI
P
The majority of the liver’s blood supply is venous blood from the gastrointestinal tract (spleen, stomach, small and large intestines, and pancreas), which is delivered to the liver via the portal vein
What cells synthesize bile acids in the liver?
How are bile salts recycled/recirculatec back to the liver?
Bile acids are synthesized from cholesterol by the hepatocytes, transported into the bile, stored and concentrated in the gallbladder, and secreted into the intestinal lumen to aid in the digestion and absorption of dietary lipids. Bile acids are then recirculated from the ileum back to the liver via the enterohepatic circulation.
What are the products of Hemogoblin degradation?
How is bilirubin conjugated and with what?
Biliverdin (Green) which is converted to Bilirubin
Bilirubin (Yellow): : bound to albumin in the circulation and then carried to the liver where it is taken up by the hepatocytes.
It is conjugated with GLUCORONIC ACID via enzyme UDP-glucuronyl transferase
Bilirubin in deconjugated to UROBILOGEN by bacterial enzymes. Some is recycled and the rest is excreted in the feces as UROBILIN and STERCOBILIN.
What is Jaundice and why do newborns can develop it?
It is a yellow discoloration of the skin and sclera of the eyes due to the accumulation of either free or gonjugated biliburin.
It can occur when there is an excessive destruction of RBCs that results in an increased production of bilirubin.
It can also occur due to the obstruction of bile ducts or with liver disease. The biliburin can’t be excreted and it is absorbed into the circulation.
The feces are light colored bc of the decreased amount of stercobilin while the urine is dark bc of high concentration of conjugated bilirubin in blood.
Newborns do not sinthesized UDP-glucunoryl transferase fast enough so they can have jundice.
Metabolic functions of the liver
Carbohydrates metabolism, proteins, and lipids.
Gluconeogenesis: the liver stores glucose as glycogen and releases it to the bloodstream when needed.
Protein metabolism: the liver sinthesizes the nonessential AAs and modifies AAs so that they may enter biosynthetic pathways for carbohydrates.
Synthesizes plasma proteins: Albumin and clotting factors. Persons with liver failure develop HYPOALBUMINEMIA
Concerts ammonia: to urea, which is excreted in the urine.
Lipd metabolism the liver participates in FAs oxydation and and synthesizes lipoproteins, cholesterol, and phospholipids. A portion of the cholesterol is converted into bile acids to help lipid digestion and absoprtion.
Detoxification in the Liver
What are examples of substances that are toxic to the body?
For example, bacteria absorbed from the colon are phagocytized by hepatic Kupffer cells and thus never enter the systemic circulation.
In another example, liver enzymes modify both endogenous and exogenous toxins to render them water soluble and thus capable of being excreted in either bile or urine.
These substances are presented to the liver via the portal circulation, and the liver modifies them in so-called “first pass metabolism”
What are Cytochrome P-50 enzymes and what is their function?
What are the conjugating substances?
Phase I reactions, which are catalyzed by cytochrome P-450 enzymes, are followed by phase II reactions that conjugate the substances with glucuronide, sulfate, amino acids, or glutathione.
Intestinal fluid and electrolyte transport
Where do we absorb electrolytes and which ones are they?
In the small intestine and colon we absorb Na+, Cl-, HCO3-, H2O, and K+
What cells secrete electrolytes?
Epethilial cells lining the crypts of the SI. These secretions contribute to the volume already in the intestinal lumen, which must be absorb.
The permeability of the tight junctions between epethilial cells determines whether fluid and electrolytes will move via paracellular or cellular route. The “leaky” junctions permit paracelluar transport.
Where does the major absorption of Na+ occur?
What is the net absorption in the JEJUNUM?
What type of transporters are present in the luminal and basolateral membranes?
What is the source of H+?
JEJUNUM net absoprtion is NaHCO3-
The mechanism consists of Na+ dependent coupled transporters (sodium comes in the cell)
The apical (facing the lumen) membrane also contains monosaccharide cotransporters (N+ glucose, glalactose, N+ ammino acid, and N+/H+ exchanger).
Na+/K+ ATPase to basolateral membrane (blood side)
Source of H+ is intracellular CO2+ H2O, which is converted to HCO3- and H+
H+ is secreted in the lumen on the N+/H+ echanger and the HCO3- is absorbed in the blood.
What type of transport mechanisms are present in the Ileum?
What is absorb in the Ileum?
It contains the same mechanisms as the Jejunum
Additinally it contains the Cl- HCO3- exchange mechanism in the apical membrane
Cl- transporter on the basolateral membrane (instead of the HCO3-)
Both HCO3- and H+ are secreted to the luminal side via Cl-/HCO3- echanger
The result is movement of NaCL into the cell, where it is absorb
The colon and similarities to renal principal cells and absorption
Na+ absorption and K+ secretion
It is induced by aldosterone
Increase number of Na+ channels allows Na+ entry across apical membrane, which leads to increase K+ pump into the cell via Na+/ATPase. Ultimately, leads to secretion of K+ and it is dependent on the flow rate. It can cause HYPOKALEMIA due to high flow rate of intestinal fluid and diarrhea.
Intestinal secretion and diarrhea
Na+/Cl-/K+ cotransporter
The Cl- channels of the apical membrane are typically closed, but they may open due to hormones or neurotransmitters such as, Ach, VIP. Activation of cAMP opens the Cl- channels initiating secretion, Na+ and H2O follow. Normally intestinal Villi cells absorb it but cholera causes severe diahrrhea.
Diarrhea leads to loss of ECF, decreased arterial pressure. The RAAS system is activated by the baroreceptor mechanisms in attempts to restore BP.
Hyperchloremic metabolic acidosis with normal anion gap
Decreased surface area diarrhea
Osmotic diarrhea
Secretory diarrhea
Decreased surface diarrhea: includes infections and inflammation of the small intestine cuasing decreased absorption of fluid by the gastointestinal tract
Osmotic: is cuased by the prescence of nonabsorbable solutes in the lumen such as lactose instead od glucose and fructose from lactase deficiency.
Secretory: example, cholera. The cholera toxin moves across the basolateral cell membrane where it catalyzes ADP ribosylation of the Alpha s subunit. GTP can’t be converted back to GDP, so it permanently binds to the Alpha s subunit permanently activating cAMP and causing the Cl- Channels on the apical membrane to remain open. Na+, Cl-, H2O are unrestrictely secreted into the lumen.
Tx: Oral rehydration solution
Avian GI Physiology
What are the parts of the avian GI?
How long does an adult chicken’s GI tract can be?
In general, the intestines of birds are relatively shorter than those of mammals.
- Beak and oropharynx
- Pre-crop esophagus
- Crop
- Post-crop esophagus
- Preventricular (gandular stomach)
- Gizzard (muscular stomach)
- Duodenal loop
- Small Intestine (jejunum and Ileum)
- Ceca
- Large intestine (very short)
- Cloaca
- Vent
Adult Avian GI 200 cm
What are the choanal clefts and what does each communicate with?
2Where is the crop relative to the esophagus?
3Which one of the two avian stomach chambers is the glandular stomach and which one is the muscular stomach?
4Are there lacteals in the lamina propria of the avian small intestine?
5What structure marks the end of the small intestine ileum?
6What are the two parts of the large intestine?
7What appears to be the function of the well‐developed villi near the ileocecal junction?
8What are the three compartments of the cloaca? Which one is most cranial and which one is most caudal?
9Are gallbladders present in domestic birds?
1.
What is the name of the combined cavity of mouth and pharynx extending from beak to esophagus?
How does it function?
Oropharaynx
The roof of the cavity is the PALATE, has long median cleft (choana) that connects with NASAL CAVITY.
Shorter cleft (infundibular cleft) is opening of the auditory tubes.
The floor of the oropharynx is formed by the mandible, tongue, and laryngeal mound. The glottis is a median slit, and there is no epiglottis guarding it.
Chickens may have as many as 300 taste buds.
Salivary glands are present and are well developed but the secretion contains little amylase. Saliva provides lubrication for the boli.
Esophagus and Crop
It consist of cervical and thoracic regions
Near the thoracic inlet of the cervical esophagus there is a dilatation that forms a pouch known as the crop (ingluvies), which has a food storage function. In the thoracic region the postcrop esophagus terminates in the proventriculus. Mucous glands are abundant in the esophagus to provide lubrication for food being swallowed.
The Stomach
What are the two chambers of the stomach?
What is the second chamber also known as?
What is the Koilin?
Why is there a red-deep color?
What is the cuticle?
How does grit help digestion?
The proventriculus is the first of two chambers that comprise the avian stomach. It is the glandular or gastric stomach.
The second chamber is the ventriculus, also known as the gizzard the muscular stomach or grinding stomach
The deep red color is due to a high concentration of myoglobin. The mucosal surface of the ventriculus is lined with a thick cuticle, called koilin, a car-bohydrate–protein complex. Koilin is formed when the mucosal secretion solidifies on the surface following exposure to the low pH in the ventriculus. The cuticle protects the ventriculus from acid and proteolytic enzymes secreted by the proventriculus.
Grit is not essential for digestion, but it helps the food moves faster instead of staying in the gizzard longer.
Small intestine
What are the parts of the SI?
It continuos caudally from the ventriculus by the duodenum.
There is a duodenum loop as found in mammals.
Meckel’s diverticulum is the Yolk sac vestige about midway in the small intestine and it is used to indicate the division between the JEJUNUM ans ILEUM.
A well‐defined network of blood capillaries, connective tissue, smooth muscle, and nerve fibers are present in the lamina propria, but no there are lacteals (blind beginnings of lymph capillaries). The ileum ends with a circular ring of muscle tissue projecting into the rectal lumen that appears to serve as a valve at the ileocecocolic junction (see Figure 46.1). Entrances to the ceca are located immediately caudal to this ring.
Avian ceca and large intestine
Where does bacterial breakdown occur?
Where does the absorption og water occur?
Is there villi in the LI?
NO paired ceca present in hawks or sonbirds
The large intestine comprises the ceca and the rectum (colon).
In most birds, a right and left ceca arise at the junction of the small and large intestines and pursue retrograde courses beside the ileum to which they are attached by ileocecal folds.
In chickens, a cecum can be divided into three regions depending on development of their villi and the presence or absence of longitudinal and/or transverse folds. Near the ileocecal junction, villi are well developed and inter-digitate to form a filter that excludes coarse intestinal contents and allows fluids to enter. While early opinions considered their function to be mainly for absorption, a greater understanding and importance of the ceca is presently recognized. In this regard, cecectomy results in reduced metabolism of food, lower digestibility of crude fiber, and greater loss of amino acids. Also, bacterial breakdown of cellulose occurs in the ceca.
Rectum and cloaca
What is the vent, and bursa of fabricus?
The rectum (colon) is relatively short and links the ileum with the coprodeal compartment of the cloaca
The coprodeum is the most cranial of the three cloacal compart-ments followed in order by the urodeum and proctodeum
The urodeum and protodeum open externally through the anus
ANUS is the VENT
The BURSA OF FABRICUS is involved in immune function and it is protected dorsally from protodeum
Gastroduodenal motility
What type of contractions are present and with what frequency?
What is the sequnce in contraction?
Rhytmic contractions and they occur ~3/minute
Contraction of thin entricular muscles
2-3 peristaltic waves through duodenum
Contraction of thick ventricular muscles
Peristaltic wave through ventriculus
About 4x/hr digesta from duodenum and upper jejunum refluxes into ventriculus. This activity permits the remixing of intestinal content with gastric secretions
Extrinsic innervation does not appear to be involved in the initiation of contractions or to be significant in the regulation of the sequence.
This activity permits the remixing of intestinal content with gastric secretions
Ileal, colonic, and cecal motility
What are Antiperistalsis movements and what is their purpose?
Antiperistalsis are segmenting contractions that occur almost continuously in the colon.
Functions of the antiperistaltic contractions are (i) to move urine from the cloaca into the colon and ceca for water reabsorption and (ii) filling of the ceca.
Antiperistaltic contractions arise from the cloaca and occur at a rate of 10–14 per minute in chickens and turkeys.
Antiperistalsis ceases immediately before defecation, and the entire colon contracts to evacuate the feces.
There are major and minor contractions that occur in the ceca. The major contractions are associated with peristaltic con-tractions in the colon, whereby a series of major contractions is associated with cecal evacuation, and a single major contraction is associated with defecation. The minor contractions perform a mixing function.
Poultry Feces
What is the difference between cecal and intestinal droppings?
Cecal droppings have a chocolate brown color, homoge-neous texture, and are distinguished from intestinal droppings, which that have a greenish, granular‐textured appearance. One or two cecal droppings occur per day, while 25–50 intestinal droppings are formed.
The Liver
Where do the ducts drain into?
How many lobes does it have?
The liver is Bi-lobed. It has right and left lobes.
The duct from the right lobe is the only one connected to the gallbladder. Bile ducts drain into the distal duodenum near the location of the pancreatic ducts.
The pancreas is located within the duodenal loop. There are three pancreatic ducts that drain in the distal duedenum.
Gallbladders are present in chickens, turkeys, ducks, and geese and bile is transported to the duodenum by two ducts (one from each liver lobe).
What is food prehension?
Food is grasped by the beak and brought into the mouth by repeated upward and downward movements of the head. Following prehension, swallowing is accomplished in three phases, oral, pharyngeal, and esophageal
Digestive issues for poultry
Based on digestive anatomy
Highly digestible starch and protein are most efficient for commercial poultry
High fiber diets will not be digested well
However, free-ranging chickens will consume some fiber
Impacted crop (crop binding, pendulous crop)
Sour crop
Ruminant Digestive Physiology
The forestomachs of the ruminant are?
The gastric stomach of the rumen is?
What is the function of the rumen and reticulum and to a lesser extent the omasum?
What is the Reticulum?
The forestomachs are, the reticulum, rumen, omesum.
The gastric stmach is the abomasum
The rumen is the largest compartment (left side of the cow abdomen)
It is part of a fermentation chamber where papillae increases surface area for absorption.
Butyrate and volatile fatty acids (VFA) are produced in the rumen.
The reticulum in the fermantation vat. It has a unique honeycomb-sheped projections from its wall.
What is the overall capacity of the ruminant GIT?
60-80 gallons
The rumen 42.5 gallons
Reticulum 2 gal
Omasum 4 gal
Abomasum 4 gal
Small intestine 15 gal
Large Intestine 10 gal
Pseudoruminants have no omasum
Where in the ruminant’s GIT is the ingesta stored and saved for bacterial fementation?
What does the bacteria fement?
The rumen and the reticulum are the sites of storage of ingesta and provide a safe haven for the bacteria unique to the rumen that will ferment the plant cellulose and hemicellulose of their diet.
What is the normal pH of the rumen fluids?
What happens with high protein diets?
In the rumen the average pH is 6.7-7.0
The rumen pH usually decreases due to the higher production of volatile fatty acids
What type of bacteria is present in the ruminants GIT?
What is their digestive function?
Mammalian enzymes cannot perform this task. The cellulolytic bacteria that can break these bonds are very strict anaerobes and most are members of the Bacteroides, Ruminococcus and Butyrovibrio genera. They break the β(1→4) linkages of plant cell wall structural carbohydrates and utilize the liberated hexoses and pentoses to provide them with energy.
How does amolytic bacteria affect digestion?
Ex: Strpetoccocus and Ruminobacter
What is Rumen acidosis and how does it occur?
While many bacteria can break the α̣1→4) link-ages in starch, the amylolytic genera such as Streptococcus and Ruminobacter are particularly adept at digesting starch and sugar. Under the strict anaerobic conditions within the rumen these bacteria ferment the starches and sugars to lactic acid
The overgrowth of amylolytic bacteria can cause too much production of lactic acid, which brings the pH down to 5.7 where the cellulytic bacteria can’t survive. This condition is known as Rumen acidosis
Why are horses not affected by high protein diets as much as cows are?
Horses absorb the starches and sugars in the small intestine before they reach the colon and cecum where their fermentation occurs (hingut fermentors).
What is prehension?
What is rumination?
What are the products or fermentation?
What organisms accomplish fermentation?
Mastication during eating + rumination
Rumination = regurgitation + remastication
Microbial fermentation by bacteria, fungi, protozoa, and yeast.
The products of fermentation are: Butyrate, propionate, and acetate
Reticulum
What are three of the major functions?
Honeycomb appearance
- Form bolus for regurgitation
- Move particles to omasum
- Move particles to rumen
What is hardware disease?
Bovine traumatic reticuloperitonitis due to metal or similar damaging material ingested.
Ruminant diet
How does bacteria provide essential nutrients?
Rumen bacteria have the ability to combine nitrogen from ammonia or urea with carbon skeletons liberated from dietary carbohydrates to form all the amino acids that make up their protoplasm.
Dietary protein that the rumen bacteria can break down is referred to as rumen‐degradable protein.
Proteins are fermented to
Peptides, Ammino Acids, Ammonia, Branched-chain VFAs.
Dead microflora are digested in the small intestine
Omasum
What is meant by “many piles”?
The material from the rumen passes into the omasum via the reticulo-omasl orifice
“many piles” refers to the omasal leaves that regulate the passage of digesta to the lowe tract.
Some absorption of water and VFAs take place in the omasum
Abomasum
What glands are present in the abomasum?
It has gastric glands with many folds
They secret HCL which kills microbes and start digestion
They also secret Pepsinogen, which hydrolizes microbial and dietary protein
Abomasl contraction are abour 2-3 minutes apart, they mix the exiting material that goes to the SI and drive gas back to the rumen
Products and process of fermentation
What happens to carbohydrates, starch, cellulose, and lignin?
Sugars >>> VFA
Starch >>> Glucose >>> VFA
Cellulose >>> Glucose >>> VFA
Ligning >>> Undigested
Ruminants use VFA for energy
Lower blood glucose 60 vs. 100 mg/dl
Gluconeogenesis: use propionate to make glucose
Fat synthesis: use acetate
Urea Cycle in ruminants
Ammonia produced in rumen from protein fermentation is immediately utilized by microbes or absorbed and converted to UREA by the liver
Fates of urea:
Excreted by kidney
Recycled to saliva
Recycled to rumen
Rumen Motility
Why is rumination important?
What is the process of rumination?
Primary contractions: MIXING major coordinated movements cranial to caudal ~ 2/min
Secondary contractions: Caudal to cranial ERUCTATE GAS
Reticular contractions: associated with CUD CHEWING
Regurgitation: reinsalivation, remastication, reswallowing. It is initiated by reticular contractions and relaxation of distal esophageal sphincter. Fluids are squeeze out of bolus and swallowed. Ingesta chewed and additional saliva added. Cud swallowed and process repeated.
Complex reflex mediated by medulla. Epethilial receptors in reticulum “starch factor”
Rumination: reduces particle size, increases surface area, adds salivaOccurs when animal is resting. Begins 30-90 minutes after eating
Ruminate up to 10 hrs per day
Distal esophageal sphincter opens, inspiratory excursion with glottis closed causing negative pressure in intrathoracic esophagus, bolus of ingesta moves to esophagus.
What are they types of contractions occuring in the cow GIT?
Where are they initiated and controlled?
Three distinct types of contractions occur in the cow’s rumen and reticulum and serve three different purposes: mixing of digesta with rumen bacteria, removal of gases produced during fermentation, and regurgitation of rumen contents so that they can be more thoroughly chewed to aid their degradation by rumen bacteria.
Each type of contraction is controlled as a dis-tinct programmed reflex within the medulla in response to vagal sensory afferent information and is initiated by the vagus efferent nerves.
Where is the esthetoscope place to listen to rumen contractions?
How often do they normally occur?
Paralumbar fossa
1-2 minutes
What is eructation and why is it important?
Eructation reflex. Gases formed during bacterial fermentation in the rumen must be removed.
The reflex begins with contraction of the caudodorsal rumen. This pushes the gas cap forward toward the cardia (purple) or opening to the esophagus. At this point the ventral sac of the rumen relaxes, allowing the fluid level of the rumen to fall below the cardia. Receptors within the cardia sense the absence of fluid and presence of gas and vagal afferents trigger the medulla to cause vagal efferent neurons to open the lower esophageal sphincter and gas is propelled up the esophagus by reverse peristalsis.
Chewing the cud
What is the rumen raft?
Where does regurgitation begin?
Where does the gas pocket move to during regurgitation?
What initiates the retrogade antiperi-staltic contractions?
The raft is the fibrous material that floats on the rumen liquid.
Chewing the cud allows for a reduced particle size and increased surface area for bacterial attachment and fermentation.
Regurgitation begins with contractions in the middle of the dorsal sac
This forces raft material toward the cardia and the gas pocket moves to the caudal part of the rumen. Coinciding with this is an inspiratory effort against a closed nasopharynx and open upper esophageal sphincter that creates great negative pressure in the esophagus to bring the bolus of fibrous material (cud) into the esophagus past a relaxed lower esophageal sphincter.
The presence of the cud initiates retrograde antiperi-staltic contractions of the esophagus that propel the cud up into the mouth. That cud is chewed for a couple of minutes, swal-lowed, and another bolus is brought up.
What affects the rate of natural regurgitation?
How often does the contraction occur?
What percentage of their time should cows spend at rest digesting?
The amount of fibrous material (neutral detergent) in the diet affects the rate of regurgitation. This material can spend up tp 3 days in digestion.
The contraction should occur every 2-3 minutes. Normally, a regurgitation contraction occurs every 2–3 min between mixing contractions and eructation contractions.
At least 60%
Abomasal contractions
How do they compared with monogastric contractions/fuctions?
Food material is sent to the abomasum at a steady state. As with monogastric animals, the true stomach mixes the material with acid and enzymes and allows it to pass to the SI.
Large amount of gas is liberated from the rumen hits the abomasum where the lower pH causes the carbon dioxide to be insoluble.
How does displacement of the Abomasum occur?
When is it common?
Abomasum contracts 2.25 times per minute. Unfortunately, if abomasal contractility is greatly reduced, the abomasum can fill with gas and “float” to the top of the abdominal cavity, a condition known as displacement of the abomasum.
It is common shortly after cows calve and with porr diets or low in fiber where Hypocalcemia leads to milk fever.
Reticular groove reflex in neonetal animals
How does the milk bypass the rumen?
At birth the rumen is the same size as the abomasum. The suckling reflex, ADH, and proteins from milk causes pharyngeal afferent neuropathways to initiate the reflex. The esophageal groove connects the cardia with the abomasum.
No microbes present and the milk bypasses the rumen and goes straight to the abomasum via esophageal groove. This avoids having milk enter the rumen where it might sour and possibly destroy colostral antibodies.
Calves don’t have papillae in the wall of rumen until after 3 weeks old. Then, they star to ingest forage and concentrate (grain). Microbes start to establish as the cow licks the calf the calf picks up bacteria from the environment.
The rumen enlarges and the mucosa transforms with papillae.
Gas production in the rumen
What are the major gases produce in the rumen?
What forces gas into reticulum towards cardia?
What are the different gases and percentages found in the rumen fermentation?
CO2 and CH4
Secondary contractions
CO2 65 %
CH4 25 %
N 7%
Trace amounts of O2, H2, H2S
Up to 600 L of gases/day
What are the 5 F’s of Abdominal distension?
Fart (gas)
Fluid
Food
Fetus
Fat: visceeral/intra-abdominal fat
Important to ascertain cause of abdominal distention when examining “bloated” animal
Vagal Ingestion Syndrome
What are the types of abdominal distention?
Gradual development of abdominal distention secondary to rumenoreticular distention
Diseases result in injury, inflammation, or pressure on vagus nerve >> signs of vagal indigestion
Type 1. Free gas bloat/failure to eructate
Type 2. Failure of transport out of rumen (blockage at reticulo-omasal orifice)
Type 3: Failure of transport out of abomasum (blockage-impaction or displacement)
Type 4. Indigestion associated with advanced pregnancy
Bloat (ruminant tympany)
Overdistention of the reticulum with gases of fermentation
Frothy Bloat: primary ruminal tympany
Free-gas Bloat: secondary ruminal tympany
-Causes: esophageal obstruction (choke), interference in nerve pathways involved in eructation, grain overload leading to esophagitis and rumenitis interfereing with eructation.
Frothy Bloat
Causes and solutions
What type of cattle are most susceptible to frothy bloat?
Frothy bloat. Legumes such as alfalfa can contain high amounts of waxy substances known as saponins. These compounds, when churned within the rumen, form a frothy bloat. High surface tension.
These froth bubbles are very stable and are interpreted by receptors within the cardia as fluid. These receptors signal the medulla that the cardia is still covered with fluid. As a result the lower esophageal sphincter (purple) will not relax. The eructation reflux cannot be completed and gas cannot escape. The rumen becomes greatly inflated and this interferes with respiration.
Solution: Limit time on high-risk pastures, give antifoaming agents.
Fedlot cattle fedd high-grain diet
In this case amylolytic bacteria produce a dextrin slime that causes froth to develop in the rumen. This froth is also perceived by the sensory receptors in the cardia as failure to clear the cardia of fluid and the lower esophageal sphincter will not open.
Hardware disease
What are the results of hardware disease?
Cows are indiscriminate eaters. They often eat foreign objects including sharp material that falls into the reticulum during primary rumen contractions,
The force sharp objects penetrate the wall of the rumen and prevents the movement of rumen contents through reticulo-omasal orifice
Resulting problems depend on direction of penetration
- Liver abscess
- Pleuritis
- Pericarditis
- All accompanied by peritonitis
What are the clinical signs of Hardware Disease?
How is it diagnose?
Clinical signs include:
- Rumen motility slows/stops
- Reduced appetite
- Reduce milk production
- Fever
- Abdominal pain
- Reluctance to move
- Arched back
- Abducted elbows
- Grunt on expiration
- Withers pinch test
- Abdominal paracentesis
- Hemogram (complete blood count)
- Imaging
Treatment and prevention of Hardware Disease
Medical: administration of antibiotics and MAGNENT
Surgical: removal of rumen metal content RUMENOTOMY
Clean up the environement by removing potentially hazardous metal material
Bailing and fence wire
Prophylactic magnets can be administered to all adult cattle
Displaced Abomasum
The Abomasum is suspended loosely by greater and lesser omentum in right front quadrant of abdomen
- Left Displaced Abomasum (LDA) or Right Displaced Abomasum (RDA)
- Many factors can contribute including HYPOMOTILITY and PREPARTURIENT changes in location of intra-abdominal organs
RUMEN ACIDOSIS
What determines the rumen pH?
Rumen pH determined by
Intake of fermentable carbohydrates
Buffering capacity of rumen
Rate of VFA absorption
Abrupt increase in readily fermentable carbohydrates causes Rumen MicroFlora totransition from cellulytic to amylolytic.
Subacute Rumen Acidosis (SARA)
pH dro is not as severe due to overall accumulation of VFAs
Lactid acid production starts and will acumulate
Steps to development of SARA:
- Shortage of amylolytic bacteria allows S. bovis to grow and produce lactid acid
- Lactid acid buildup and pH drops
- Clinical signs not as severe, but feed intake decreases and milk production stops
Acute Acidosis
pH < 5..5
Lactic acid accumulation causes extreme pH drop and some of it accumulates in blood
Sometimes pH drops to <4.0 causing papillae to peel off (PARAKERATOSIS) and bacteria invade the rumen wall
Treatment/Prevention includes:
Feed ionophores, buffers, lactic acid utilizing bacteria.
Non-Rumminant Herbivore Digestive Physiology
How do humans compare to horses, dogs?
Horses have the largest cecum, and dogs the smallest
How is the ascending colon in pigs and ruminants?
It has an spiral arrangement of coild in a cone shape
Ruminants have a spiral colon
The transverse colon is relatively short in a horse
Sigmoid colon in humans
What are the two major types of fermentors?
Where does the fermentation occur?
Pregastric fermenters: Ruminants
Foregut fermenters: Non-ruminant herbivores
Hindgut fermenters: Non-ruminant herbivores
- Cecal fermenters
- Colon Fermenters
* Whether an animal fements before or after the gastric stomach and SI has a huge effect on efficiency of utilization of fermentation products.
Non-ruminant herbivores
What type of modification do they undergo for microbial fermentation?
What animals are included in this group?
GIT modifications to facilitate microbial fermentation
Horse, rabbit, guinea pig, zebra, elephant, hippopotamus, kangaroo.
Groups:
Foregut fermenters
Cecal fermenters
Colon fermenters
Adaptations for fermentation in herbivores
When is microbial fermentation useful?
What are the three factors for utilizing microbial fermentation?
Microbial fermentation useful if digestive system can retain digesta and microbes for long periods of time
-Maintain an environment suitable for fermentation
Factors:
- Volume available for fermentation: greatest in ruminants
- Retention time
- Microbial populations similar in most species
Foregut Fermenters
How is their stomach?
What animals are foregut fermenters?
They have a compartalized stomach
Meaning it has one or more pouches for fermentation separate from the gastric region “pre-gastric” fermentation
Foregut fermenter can be bulk roughage feeders or browesers
-Sloth, Colobus monkey, Kangaroos and Wallabies, Hippopotamus.
*None of the non-ruminant herbivore domesticated species are foregut fermenters
How long is the body length of a Sloth, Kangaroo, and Colobus Monkey?
Sloth: 55 cm
Kangaroo: 115 cm
Colobus Monkey: 50 cm
What animals are Cecal fermenters?
How is their digestibility of fiber?
Where does the separation of particles occur?
Rodents and lagomorphs
Rabbit, Guinea Pig, rodents
Because cecum is a blind sac, digesta must pass out via route of entry. Allows cecum to selectively retain certain fractions of feed
Cecal content enter colon 1-2 times/day
Digestibility of fiber is very low. They evolved an strategy to separate and excrete indigestible fiber
The separation of particles is based on density of colon
They produce two types of feces:
- Hard Feces:
- Soft Feces (night feces):
Colon fermenters
What animals are colon fermenters?
Why are they less efficient than foregut fermenters?
Equids, Elephants, Koalas
Enlarged colon and cecum for microbial fermentation
-Ferments material that resists breakdown in SI
Highgut fermentation is superior because the HCL from gastric stomach does not kill the bacteria that is necessary for fermentation.
Hidgut fermentation is BEFORE GASTRIC abd SI
Hindgut fermenters
What is the primary site of fermentation?
What is the Haustrae?
Hindgut fermentation is limited in omnivores and herbivores
Hindgut: primary site of microbial fermentation and digestion of cellulose. Also, mixing contents.
The Ileum and colonic epethelium secrete HCO3-
Volatitle Fatty Acids are products of fermentation used for energy: Acetate, Butyrate, Propionate
Haustrae in Cecum and ascending colon
Motility in Cecum: Haustrae contract and expand
Motility in Ascending Colon: Segmentation and Haustral contractions
Transit rate is slow in Colon
Large quantities of VFAs produced and absorbed, but microbial protein wasted.
