Digestive System Ruminants Dentition Restraint Dentition Cattle Incisors

Digestive System Ruminants

Dentition • Restraint

Dentition - Cattle Incisors Pre-molars Molars Deciduous: 20 (there are no deciduous molar and deciduous PM 1) 0 0 3 (I C PM) 313 Permanent: 32 (No PM 1) 0033 3133

Eruption – Deciduous Teeth Age at eruption 1 st Incisor (Di 1) Birth – 2 weeks 2 nd Incisor (Di 2) Birth – 2 weeks 3 rd Incisor (Di 3) Birth – 2 weeks 4 th Incisor (Di 4 or C) Birth – 2 weeks 1 st Cheek Tooth (Dp 2) Birth to few days of age 2 nd Cheek Tooth (Dp 3) Birth to few days of age 3 rd Cheek Tooth (Dp 4) Birth to few days of age

Deciduous Permanent

Eruption – Permanent teeth Teeth I 1 I 2 I 3 I 4 or C 1 st cheek tooth P 2 P 3 second cheek tooth P 4 third cheek tooth M 2 fifth cheek tooth M 3 sixth cheek tooth Age at eruption 18 – 24 months 24 – 30 months 36 months 42 – 48 months 24 – 30 months 18 – 30 months 30 – 36 months 24 – 30 months

Cattle - Dentition • 14 months: – complete deciduous – short and broad – bright ivory color – space between Di 1 incisors

How old? Rostral • Teeth are longer and narrower • Not touching at upper corner Rostral - lateral

How old? Eruption of one or more central incisors

How old? At least one of 2 nd pair of incisors

How old? I 3: 36 months, I 4: 42 months Peg teeth

Dentition – Sheep and Goats • • 2 (0/4 incisors, 3/3 pre-molars, 3/3 molars) = 32 Animal under one year old: no permanent teeth One year old (2 permanent teeth) Two years old (4 permanent teeth) Three years old (6 permanent teeth) Four years old (8 permanent teeth) Old animal, more than four years old

Permanent Tooth Eruption • • Incisor (I 1)1 -1. 5 years Incisor (I 2)1. 5 -2 years Incisor (I 3)2. 5 -3 years Incisor (I 4)3. 5 -4 years Premolars 1. 5 -2 years Molar (M 1)3 months Molar (M 2)9 -12 months Molar (M 3)1. 5 -2 years

How old- Sheep? Wide spacing Broken mouth

How old - Goats Deciduous – 2 weeks 1. 5 – 2 yrs Deciduous – 10 months 3 yrs 10 yrs

Digestive System • Cranial fermentors – – Forestomach E. g. cattle, sheep and deer digest and extract energy from cellulose utilize the protein from fermentative microbes • Caudal fermentors • • Cecal digestors E. g. horses and rabbits digest and extract energy from cellulose utilize dietary hexose sources directly

Digestive system calf • Esophageal groove – first few weeks of life, the rumen, reticulum, and omasum are undeveloped – By pass reticulum and rumen and goes directly into abomasum – Grain and forage for rumen development ~ 3 weeks age

Fermentation Ecology • Rumen inoculation – 1 ml of rumen content: ~10 to 50 billion bacteria, 1 million protozoa, variable numbers of yeasts and fungi – Cellulolytic (digest cellulose) – Hemicellulolytic (digest hemicellulose) – Amylolytic (digest starch) – Proteolytic (digest proteins) – Sugar utilizing (utilize monosaccharides and disaccharides) – Acid utilizing (utilize such substrates as lactic, succinic and malic acids) – Ammonia producers – Vitamin synthesizers: vitamin B and K – Methane producers

Fermentation Ecology • Rumen p. H between 6 and 7 • Grain engorgement: p. H <5. 5 – protozoal populations decrease • Products: Sugars -> VFA’s – acetic, propionic and butyric acids

Volatile Fatty Acids • Acetic acid – is utilized minimally in the liver – oxidized throughout most of the body to generate ATP – Major source of acetyl Co. A for synthesis of lipids. • Proprionic acid – is almost completely removed from portal blood by the liver – In the liver, proprionate serves as a major substrate for gluconeogenesis, which is absolutely critical to the ruminant because almost no glucose reaches the small intestine for absorption. • Butyric acid, – most of which comes out of the rumen as the ketone beta-hydroxybutyric acid – is oxidized in many tissues for energy production.

Ruminant Anatomy • the rumen or paunch • reticulum or "honeycomb, " • the omasum or “book, " • the abomasum or "true stomach. "

Rumen – ‘Paunch’ • largest of the forestomaches • sacculated by muscular pillars: dorsal, ventral, caudodorsal and caudoventral sacs • stratified squamous epithelium • fermentation vat (25 gallons) • Absorbs most VFA • Healthy cows: 1 -2 minutes/contractions

Reticulum – ‘honeycomb’ • Lies against the diaphragm • rumino-reticulum connected by tissue • Heavy objects fall • Hardware disease (traumatic reticuloperitonitis) • No enzymes secreted

Omasum - book • broad longitudinal folds or leaves • absorbs water and other substances from digestive contents • Reduce particle size, ingesta between the leaves will be drier than in other compartments

Abomasum – true stomach – This is the only compartment (also called the true stomach) with a glandular lining – HCL and digestive enzymes (mucin, pepsinogen, renin, lipase), needed for the breakdown of feeds, are secreted into the abomasum

Digestive system - Ruminants • • • The small intestine – measures about 20 times the length of the animal – duodenum, jejunum, and ileum. – secretions of the pancreas and the gallbladder, which aid digestion – Most of the digestive process is completed here, and many nutrients are absorbed through the villi (small finger-like projections) into the blood and lymphatic systems. Cecum – junction of the SI and LI, where some previously undigested fiber may be broken down – Function of cecum? Large intestine – last segment of the tract through which undigested feedstuffs pass – absorption of water is the primary digestive activity occurring in the large intestine – Some bacterial digestion of undigested feed occurs

Function of digestive tract • • • Eructation (belching) – Large quantities of gas, mostly carbon dioxide and methane, are produced in the rumen Rumination – 35 to 40 percent of each day ruminating (cud chewing) – During rest periods, feed boluses (cud) are regurgitated for rechewing to reduce particle size and for resalivation. – Feed is more readily digested by rumen microbes as particle size is reduced Motility of the rumen and reticulum – contractions mix the rumen contents, bring microbes in contact with new feedstuffs, reduce flotation of solids, and move materials out of the rumen Saliva production – 50 to 80 quarts of saliva – provides liquid for the microbial population, recirculates nitrogen and minerals, and buffers the rumen – buffer for helping to maintain a rumen p. H between 6. 2 and 6. 8 for optimum digestion of forages and feedstuffs Vomiting – Rare: suspect toxins

References • • • Large Animal Clinical Procedures, Elizabeth Hanie. 2006 http: //www. fsis. usda. gov/ofo/tsc/bse_information. htm http: //www. fao. org/docrep/t 0690 e 05. htm http: //www. infovets. com/books/smrm/C/C 015. htm http: //www. vivo. colostate. edu/hbooks/pathphys/digestion /herbivores/index. html • http: //www. extension. umn. edu/distribution/livestocksyste ms/components/di 0469 -02. html • faculty. fortlewis. edu/LASHELL_B/Nutr 2 Rumdigestion. pdf • http: //www. das. psu. edu/researchextension/dairy/nutrition/calves/rumen