ANFS 101 Exam 2

digestion

-physical and chemical changes that feeds undergo in the gastrointestinal tract

-release of nutrients for absorption

Classification of Digestive Systems

-carnivores, omnivores, herbivores

1. Monogastric

2. ruminant

Monogastric (Classification of Digestive Systems)

-non-ruminant

-simple (one) stomach

-cecal fermentation, bacteria producing compounds in cecum -> fibrous feeds

Ruminant (Classification of Digestive Systems)

-compartmentalized stomach before true stomach

-complicated fermentation -> fibrous feeds

-3 big compartments, followed by true stomach

BACTERIA IN MAMMALS

-mammals do not have enzyme cellulase to break down cellulose, so need bacteria in their body to produce it!

Carnivore vs. omnivore

-carnivore=simpler digestive tract

-omnivore=complex digestive tract

enzymes

-organic catalysts which promote change

-composed of amino acids

absorption

-passage of nutrients released in digestion, through intestinal wall to circulatory system

metabolism

-where carbs and fat turn into energy

-amino acids recombined to make proteins, hormones, enzymes

-utilize nutrients to make products

4 Steps to Utilize Ration

1. digestion

2. absorption

3. circulation

4. cellular metabolism

Steps of Digestion

1. prehension

2. mastication

3. saliva secretion

4. deglutition

Prehension (Steps of Digestion)

-1st step

-lips (horse), teeth (sheep), tongue (cow) -> process of gathering food

Mastication (Steps of Digestion)

-2nd step

-mechanical break down, aka chewing

-increase surface area (exposed to more enzymes, more easily digested)

-ruminants: rumination!

Rumination (Mastication)

-how ruminants chew their food

-"chewing cud"

-regurgitate their food to chew again

Saliva Secretion (Steps of Digestion)

-3rd step

-lubricant, pH -> gets foamy due to O2 from fermentation which causes gas!

Deglutition (Steps of Digestion)

-involuntary (neural control)

-peristaltic waves

-"swallowing"

Monogastric Stomach

~proventriculus in birds

~abomasum in cattle

-has several functions

1. physical breakdown (churning, mixing)

2. chemical breakdown (enzymes, acids)

a) HCl denatures proteins

b) acidic, helps enzymes work

3. enzymatic breakdown

a) pepsin: proteins

b) renin: milk

c) lipase: lipids

Monogastric Stomach to Small Intestines

-chyme: when food gets to stomach, becomes acidic

-mixed with alkaline secretions:

a) bile: formed in liver, stored in gall bladder, emulsify fats and lipids to increase surface area

b) pancreatic juice: trypsin, chymotrypsin, etc.

Small Intestine

1. duodenum: bile and pancreatic secretions dumped here (food breakdown)

2. jejunum: villi, in charge of absorption, increase absorptive surface area

3. ileum: absorption

DIARRHEA?

-destroys villi in jejunum so cannot absorb

Where does the nutrients absorbed go?

-into the lymph systems or circulatory system

-then to liver and distributed

Process of Absorption

-active process -> requires energy

-small intestine (most done here)

-villi -> have extensive capillary network to pick up nutrients

-portal vein to liver

Large Intestine

-no villi, absorption restricted

-no enzymes

-3 parts (capacities vary)

1. colon

2. cecum

3. rectum: excretion

-functions:

1. water, electrolytes, vitamins, minerals, VFAs all absorbed

2. feces 50% bacteria by weight

Cecum (Large Intestine)

-functionality varies

a) monogastric herbivores: lower quality feed, ability to absorb less

-cecum contains bacteria to break down grass, can't consume bacteria since after sight digestion, but still get VFAs

b) omnivore: decent cecum in adults

c) carnivores: NO cecum, can't process VFAs!

cecotrophy

-consume contents of cecum (poop) to get benefits of bacteria

-rabbits

VFAs

-volatile fatty acids

-primary energy source for ruminants and non ruminant herbivores

Removal of Waste

1. defecation: pooping, quantity related to how much digested

-consists of undigested feed, sloughed cells, bacteria

2. micturition: urination

-water and nitrogen compounds (excess proteins)

-urea in mammals

-uric acid in birds

Digestion in Pig

-only farm animal where salivary amylase is secreted in saliva, since pH in stomach to low for amylase to work: begins to break down starch in feed (can taste sweet :)

*little nutritional importance

-enzymes in gastric juices are ones expected in monogastric animals

-digestions of protein completed in intestine

-most fat digestion occurs in small intestine

-all that gets to jejunum = AAs

-pancreatic juice: contains enzymes that aid in digestions, sodium carbonate and bicarbonate to neutralize stomach acid

-pancreas also produces insulin (important in carb metabolism)

-BILE: digestion and absorption of fats (Fat-soluble vitamins)

Digestion in Ruminants

-complex stomach

-different digestions, allow animal to use some roughage (cellulose) as source of energy

-microbial populations (bacteria) ferment feed

-end products of fermentation provide nutrients to animal that would otherwise be unavailable

-fills rumen (big storage container) rapidly

~take little or no time to chew

~finds place to rest and chew

-perform rumination (feed increase in surface area)

Rumen Compartments

1. rumen

2. reticulum

3. omasum

4. abomasum (true stomach)

Rumen (Rumen Compartments )

-aka paunch

-anaerobic fermentation -> bacteria attach to indigestible fiber and produce fatty acids which are absorbed through papillae into small intestine

-produces VFAs (energy source)

-produce proteins

-proteins gas -> eructation, if no gas leaves, animal can't intake anymore feed

-food storage

-main functions: site of anaerobic bacterial fermentation, store food, bacteria digest carbs to produce VFAs

Reticulum

-aka honey comb

-fermentation

-pacemaker for rumen contractions to mix

-aka "hardware stomach"

Omasum

-"many piles"

-probably water, electrolytes, and VFAs absorbed

-reduces particle size

Abomasum

-true stomach

-ruminants can digest stems/stalks -> all nutrients and microbes end up here

-lined with mucous membrane, gastric juice secreted

-from abomasum to anus , ruminant tract like monogastric

Benefits of Microbial Fermentation

-microorganisms make protein

-bacteria convert non-protein nitrogen (urea) into bacterial protein

-bacteria pass down tract with the feed

-digested in abomasum and small intestine

-bacteria contain energy, vitamin K, water soluble vitamins (NOT A, D, E)

-produce VFAs!!!!!!!!!!!!!!!!

Eructation in Ruminants

-BURPING

-very important

-large quantities of gas produced by rumen microorganisms removed

-belched out of rumen - enters lungs and breathed out

Fermentation Process

-microorganisms and ruminants live in symbiosis

-animal benefits since microbes digest feeds and generate nutrients they can't

-ruminal environments = ideal living conditions for microbes: warmth, moisture, food, dark, anaerobic, removal end products

-bacteria specialize in digesting specific carbs, proteins, acids -> produce ammonia, vitamins, methane

-40 species of ciliate protozoa

Volatile Fatty Acids

-major product of fermentation

-may produce 50-70% of total energy needs of animals!

Fermentation

-protein broken down by microbes into ammonia and organic acid

-microbes use ammonia to make AAs for own use

-high levels of fat=bad for microbes (Reduce ability to function)

-gas and heat produced -> heat can be used to warm the animal

Advantages of Fermentation

-has potential to digest poor quality feeds and increase feeding value

-essential nutrients not found in diet made my microbes

Disadvantages of Fermentation

-has potential to decrease quality of high quality feeds -> since microbes eat it first!

-requires lots of energy

Digestion in Avian

-organs similar to those in monogastric, but lack of teeth and have gizzard and crop

-gizzard, small intestine, two ceca, large intestine, cloaca

Crop (Digestion in Avian)

-dilation of esophagus, food storage and moistening

-in some species, fermentation in crop

Proventriculus (Digestion in Avian)

-equivalent to glandular stomach in mammals, abomasum in ruminants

-gastric juices production (HCl and pepsin)

-ingesta passes through in matter of seconds, little digestion takes place

Gizzard

-grinding organ, no enzymes secreted but enzymes from proventriculus work in here

Small Intestine (Avian)

-function like other monogastric, no specifically separated jejunum/ileum

Two Ceca

-at junction of small and large intestine

-size influenced by type of diet (larger when more fiber)

-modern chicken=small ceca, no use

Large Intestine (Avian)

short, not divided into rectum/colon

Cloaca

-common orifice for waste (feces, urine, copulation, egg laying)

Digestion in Horse

-non-ruminant herbivore (monogastric)

-capable of using roughage

has active cecal bacteria population

-prehension with flexible upper lip, teeth, tongue

-saliva doesn't have enzymes, just lubricant

-vertical and lateral jaw movement

-saliva -> 10 gallons a day!

-one way peristalsis, cannot regurgitate

-horses=continuous eaters, can't store as much in stomach as cattle

Equine Stomach

-important distinctions compared to other mammals

-capacity=smaller, like pig

does not have equivalent muscular activity so more susceptible to stomach disorders like colic and ruptured stomachs (stare at belly, lie down and roll around)

-small intestine, large intestine, cecum, large colon

Small Intestine (Horse)

-similar to monogastric, but absence of gall bladder (which is why horse=continuous eater)

Large Intestine (Horse)

-divided into cecum, large colon, rectum

-60% total gut capacity

Cecum and Large Colon (Horse)

-contain all bacteria that produce water soluble vitamins

-site of bacterial fermentation, which produces VFAs

-absorbed through cecum and colon wall, then used by animal

-on forage diet receives majority of energy from VFAs

-bacterial synthesis of proteins occurs, but horse can't use since past site of digestion already, coprophagy (bad feces eating) only happens in horses on poor diet

-soluble carbs digested, absorbed in small intestine

-fiber fractions fermented in large intestine and colon

-only 2/3 effective at fiber digestion as ruminant -> some passed site of digestion/absorption

-ALSO horses have faster tract -> no regurgitation. faster rate of passage, less time for enzymes and bacteria to breakdown food

genotype

-animal's genetic makeup, GENES

-sets stage for disposition, coat color, speed, gait types, disease resistance, etc

-combo of genes and environment

-expression of genotype into traits of economic importance provides basis for animal's worth when marketed

Genetics and Animal Breeding

-study of heredity

-transmission of traits from mated animals to progeny

-based on genotype and phenotype

phenotype

-what you see, expression of genotype

chromosomes

-rod-like structures in nucleus

-paired

-composed of DNA strands

genes

-sequences of DNA on chromosome

-specific linear sequence of DNA nucleotides

-locus=position

-allele=specific form

DNA/RNA

-DNA: made of repeating nucleotide molecules

-nucleotide: deoxyribose and phosphate base (A, T, C, G)

-gene=specific linear sequence of DNA nucleotides

DNA Replication

-unzip double strand

-form complementary mRNA made by transcription

Translation

-mRNA leaves nucleus to take info to ribosomes which translates genetic code

-manufacturers chain of AAs from info found in the specific DNA sequence of a gene

Inheritance

-way alleles passed on

-homologous chromosomes: genes that affect same trait

-alleles: form of gene which affects same trait

a) homozygous= matching alleles at given locus

b) heterozygous= different alleles at given locus

Number of Chromosomes

-species specific

-chromosomes occur in pairs in somatic cells

a) somatic cells contain diploid (2n)

b) germ cells (sperm and egg) have haploid (n)

Sex Chromosomes

-homogametic: XX female

-heterogametic: XY male

-OPPOSITE IN BIRDS

Mitosis

-process of somatic cell division

-replication of cells

-diploid undergoes, end up with 2 diploid cells

Meiosis

-gametogenesis: development of sex cells

-diploid to haploid

-forms cells that contain half of genetic message

-2 divisional procedures:

1) one diploid divides into 2 haploid

2 )two haploids replicate, 4 haploid cells

Spermatogenesis

-occurs in seminiferous tubules, each diploid cell forms 4 haploid cells

-continuous, starts @ puberty

-may be seasonal (rams)

Oogenesis

-occurs in ovary, each diploid forms 1 haploid

-first step completed during embryonic and fetal development

-female is born with all potential ova she will ever have

Fertilization

-union of haploid sperm and haploid ovum

-sample of genetic info from each parent combined

Gene Expression

-recombined alleles

-dominant B, recessive b

-co-dominance= express both

-incomplete dominance= express neither completely

-epistasis= one gene pair influences another, one gene prevents another from expressing ex: coat color

Qualitative Traits

-phenotypes classified into groups

-usually controlled by 1 gene pair

-ex: coat color, horns

-more important in pets

Quantitative Traits

-phenotypes can be measured

-controlled by many gene pairs

-influenced by environment

-ex: how much milk, how strong

-more important in livestock

Heritability

-measure of proportion of phenotypic variation that can be passed form parent to offspring

-differences due to genetics and environment

-part of what you see due to genetics

-range of values is 0-1, closer to 1=more influenced by genetics

-known for important quantitative traits

-indicative of genetic progress w/ selection

Animal Breeding

-selection of best

-selection differential : how much better best are vs. the rest

-multiply by heritability to get progress

-heterosis or hybrid vigor: (cross-breeding) offspring outperform average of parents, inversely related to heritability

Systems of Mating

1. inbreeding

2. outbreeding

3. cross-breeding

inbreeding

-closely related individuals decrease variation

-more genetic diseases

outbreeding

-individuals less closely related than average population

cross-breeding

-different breeds bred

Animal Model

-mathematical model used in breeding

-predicts breeding value (used by livestock producers during purchases)

-calculates EPDs

-all data goes into database

-breeding value= estimate of transmitting ability

-EPD: half of breeding value, predication based off data

EPD

-estimated prodigy difference

Beef Cattle Breeding

-based on EPD and ACC (accuracy)

-plus or minus unit normally expressed

-birth, weaning, yearning weight in pounds

-maternal milk in pounds

-carcass traits in inches or millimeters

-scrotal circumference (bulls) in centimeters

Why do bulls have more data?

-can obtain semen from bull and impregnate hundreds of cows, so will have hundreds of offspring, and more data

-females can only have one calf a year -> have less data!

Accuracy

-measure of reliability associated with EPD

-expressed as value between 0 and 1

Sire Summaries

-include EPDs, accuracies, graphs of average change in EPD for particular breed, breed avg EPDs

-possible change values, other useful materials

-huge database!

Genetic Evaluation

-contemporary group: group in which animals of given sex and age, having smilier treatment, given equal opportunity to perform

-ex: Angus calves have 2.3 EPD for birthweight, which means calves on average are 2.3 lbs greater than parent

Beef Cattle Genetic Improvement

-heritability

1. reproductive traits have low heritability (< 0.2)

2. growth traits have moderate heritability (0.2-0.4)

3. carcass (meat) have high heritability (> 0.4)

Use of EPDs

-purchase of breeding stock

-EPDs within breed = directly comparable between herds

-EPDs cant be compared between breeds

Dairy Cattle Genetic Improvement

-one advantage = focus on limited number of economically important traits

-milk yield -> primary driver in trait emphasis for profitability

-dairy producers challenged to balance traits of economic importance to address some of the following goals

a) achieve profitable milk yield levels

b) monitor milk composition

c) generate profitable replacement animals that are productive under stress of high production level

d) sustain and improve cow longevity in herd

DHI System

-Dairy Herd Improvement

-much of genetic improvement in milk production in US = attributable in part due to good use of performance records through DHI

-consists of comparing sire daughters with contemporaries in same herd

Animal Model

-produces predictions of breeding (genetic) value of animal

-compiles lactation yield info for economically important traits

~milk, fat, protein, somatic cell score, productive life, pedigree

-USDA-DHI Animal Model Genetic Evaluation generates some basic values

~PTA= predicted transmitting ability

~REL= reliability (%R) measure of accuracy, or amount of info in an evaluation

-producers benefit from extensive herd summary reports provided by DHI

-herd analysis and management reports include production, reproduction, genetics, udder death, feed cost

-report useful in verifying number of replacement and producing animals in the operation

Swine Breeding

-extensive records within herds

-STAGES: across herds

-high reproduction rate

-short generation interval: can get pregnant at 7 months, can have first litter at 12 months, so rapid genetic progress

-herd reproductive measures:

a) pigs per sow per year

b) pregnancy percentage

c) farrowing percentage (giving birth)

d) weaning rate percentage (how many piglets survive)

e) live pigs per litter

f) mated female to service boar ratio

Swine Performance Information

-growth rate and feed efficiency are ovulated extensively in swine production

-economically important measures:

a) days to 250 lbs -> less time to get to 250 means sells sooner and then pay less money for feed

b) average daily gain (ADG)

c) feed efficiency = pounds of feed it takes to produce one pound of weight gain

-body composition and carcass meat = important to producers and consumers

-Data collected:

1. backfat thickness (live, negative trait)

2. carcass fat depth -> want smaller strip of fat along edge

3. loin eye area -> sign of meat

4. pounds of lean pork (muscle)

5. loin muscle color, firmness, marbling

Swine Genetic Improvement

-STAGES: Swine Testing and Genetic Evaluation System

-incorporates performance info to generate breeding values (basically within herd EPDs)

-national evaluation run for specific herds to generate across herd EPDs

Sheep Breeding

-2 trais

1. meat

2. wool

-3 breed groups

1. ewe: easy breeders

2. ram: meat/muscle

3. dual: good at both, used for wool too

Sheep Genetic Improvement

-major areas of economic importance are lamb growth, prolificacy (how many kids at birth), quality/quantity of wool

-EPDs only available since 1986, not yet as useful

-artificial insemination rarely used

NSIP

-National Sheep Improvement Program

-designed to produce purebred and commercial producers with performance records and genetic evaluation

-evaluates maternal traits, growth traits, wool traits, developing carcass traits

-some breed associations using across-flock genetic evaluations through NSIP

SUMMARY OF GENETICS AND BREEDING

-DNA codes for proteins

-mitosis/meiosis

-breeding techniques help manipulate genetic code

-EPD: estimated prodigy difference

-DHI: genetics in dairy

-STAGES: genetics in swine

-NSIP: genetics in sheep

Reproduction

-reproductive traits: low genetic, high environment

-coordinated processes: germ cell development, fertilization, pregnancy, parturition (giving birth)

-endocrine system -> hypothalamus an pituitary gland give signals to gonads through hormones which causes physiological changes

Puberty

-non-functional endocrine/reproductive state to gamete and hormone production

-reproductively competent

-influenced by age and weight

a) in species where mature @ similar rates, depends on age (pigs)

b) in species where matures @different rates, depends on weight (cattle)

-development of secondary sex characteristics