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Estrous Cycle
- Days from the beginning of one estrus period to the next
- days from one ovulation to the next
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Estrus
- Receptivity to the male
- Stands to be mounted
- "In heat"
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polyestrous
- several estrus periods per year
- cow, sow
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Long day breeder
- controlled by day length and time of year
- spring breeders - mares, wild birds
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Short day breeder
- controlled by day length and time of year
- fall breeders - ewe, deer
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Which farm animal female ovulates after she goes out of estrus?
cow
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When they are cycling regularly, farm animals come into estrus and ovulate about every
- 21 days
- Exception: Ewe (17 days)
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Myometrium
- layers of muscle in the uterus
- oxytocin makes this contract, which moves the sperm along
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endometrium
- "inside the uterus"
- lining of the uterus and the source of PGF2a
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Site of fertilization?
The ampulla of the oviduct
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Follicle
- located in the ovary
- ovum develops into the follicle
- some develop into the maximum size
- produce estrogens
- mature follicles rupture because of LH surge, freeing the ovum (ovulation)
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Corpus hemorrhagicum
- "Bloody body"
- a blood clot formed in the cavity after the rupture of the mature ovarian follicle during ovulation
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Corpus Luteum
- Produces progesterone
- "Yellow body"
- Cells of follicle change into the CL
- During pregnancy, CL continues to function, preventing estrous cycles and producing progesterone
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Source of GnRH (Gonadatropin Releasing Hormone)?
Hypothalamus
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Function of GnRH in female?
- Release of FSH and LH
- GnRH is released in the presence of estrogen, when progesterone levels are low
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Source of FSH (Follicle Stimulating Hormone)?
Anterior Pituitary
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Purpose of FSH in females?
Stimulate follicle growth and estrogen production
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Luteinizing Hormone source?
Anterior Pituitary
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Purpose of LH in females?
- Surge of LH initiates ovulation
- CL formation
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Estradiol source?
Ovary - follicle
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Purpose of estrodial in females?
Estrus - mucus secretion, etc.
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Source of progesterone?
CL
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function of progesterone?
maintenance of pregnancy, inhibits release of LH and FSH
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Prostaglandin F2a Source?
Endometrium, among others
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Prostaglandin F2a function?
Lyses CL
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Oxytocin function?
Gamete transport, uterine contraction, milk let down
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Oxytocin source?
Posterior pituitary
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Two components of semen?
seminal plasma and spermatazoa
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Where is seminal plasma produced?
accessory glands
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where are spermatazoa produced?
in the seminiferous tubules located in the testicle
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where does sperm maturation and storage take place?
epididymis
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Where is testosterone produced?
by the interstitial cells of Leydig
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When a testicle is retained in the abdominal cavity the male is called what?
cryptorchid
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In a cryptorchid, the retained testicle produces testosterone but not viable spermatozoa why?
Testicle is too hot
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When cattle are artificially inseminated, what kind of semen is used?
frozen
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When sows or gilts are inseminated, the semen is usually stored at what temperature?
- 55 degrees
- Boar semen does not recover well from freezing
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Most mares are housed and artificially inseminated on the same farm as the stallion with what type of semen?
fresh
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What types of analogs are used to aid in estrus synchronization by lysing or destroying the CL?
Analogs of prostaglandin
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What types of analogs are used to aid in estrus synchronization by mimicking the action of the CL and preventing estrus or ovulation?
Analogs of progesterone
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What's a CIDR used for?
- To administer exogenous progesterone inter-vaginally when synchronizing estrus in cows and ewes
- Controlled Internal Drug Release
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An advantage of using ultrasound compared to rectal palpation in diagnosing pregnancy?
It can be used earlier than rectal palpation
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Purpose of LH in males?
Sperm production
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Function of estrodial in males?
Testosterone production
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Source of testosterone?
Testicles (interstitial cells of leydig)
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Gestation length for cow?
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Gestation length for ewe?
- 145-150
- About 4.8 - 5 months
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Gestation length for doe/nanny?
-
Gestation length for mare?
-
gestation length for a sow?
- 114 days
- 3.8 months
- most preidctable
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Gestation length for a human?
266 (38 weeks)
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What is the length of the cow's estrous cycle, how long is she in estrus for and when does she ovulate?
- Cycle - 21 days
- Estrus - 12-15 hours
- Ovulates - 12 hours after
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What is the length of the ewe's estrous cycle, how long is she in estrus for and when does she ovulate?
- Cycle - 17 days
- Estrus - 36 hours
- Ovulation - 6 before end
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What is the length of the doe (goat) estrous cycle, how long is she in estrus and when does she ovulate?
- Cycle - 21 days
- Estrus - 40 hours
- Ovulation - 12 before end
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How long is a sow's estrous cycle, how long is she in estrus and when does she ovulate?
- Cycle - 21 days
- Estrus - 48 hours
- Ovulation - 12 before end
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How long is a mare's estrous cycle, how long is she in estrus and when does she ovulate?
- Cycle - 21 days
- Estrus - 5-7 days
- Ovulates - 24 hours before end
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Purpose of studying animal science?
- Increase understanding of the biology of animals
- Increase efficiency (increase productivity, decrease costs)
- Produce superior animal products and increased nutrient density
- Develop biotechnologies to enhance production
- Develop products that improve the quality of life for humans
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Beef industry in MO?
- 2nd in nation in total beef cow numbers
- 2 million cows on 68,000 farms
- Average herd size 34 cows
- $1B annually
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Dairy industry in MO?
- 20th in US
- 115,000 dairy cows and 1,760 licensed producers
- SW MO home to thriving grass-based dairy program
- New Zealand invested $50 million
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Equine industry in MO?
- 3rd in US
- 200,000 horses at 37,000 locations
- Estimated value at $420 Million - second only to beef cattle and calves
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Swine in MO?
- 6th in US
- 6.3 million pigs on 4,000 operations
- Declining industry (in number of operations)
- 1994-10,000 operations, 1998 5,000
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Difference between arable and cultivated land?
- Arable can be used for growing crops and is ideally suited for cultivation
- Cultivated land is actually being used to grow crops, requires extensive inputs
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Is there sufficient food production to provide for the current world population? If so, why are people hungry?
- Yes - Ag produces 17% more calories per person than 30 years ago
- Provides 2,720 KCal per person per day
- But- insufficient land to grow or money to buy enough food
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What percent of the US population is actively involved in the production of agriculture?
Less than 2 percent
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How are humans and animals able to utilize cellulose (the most abundant organic compound on earth)?
- Microbes help us out. They produce cellulase, which break the beta bonds.
- Microbes get the glucose, mammals get volatile fatty acids, which are used for energy
- Microbes ferment the cellulose
- Nonruminants have smaller fermentation vats than ruminants
- Ruminants have a fermentation vat comprised of 3 chambers and a true stomach - they provide a way for humans to "harvest" cellulose
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Cellulose is glucose linked by beta-bonds. Can mammal enzymes degrade it?
Nope. We need microbes to produce cellulase to break the beta bonds. They use the glucose for themselves.
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Why are ruminants a way for humans to harvest cellulose?
They turn grass into beef
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Livestock receipts account for what percentage of all agriculture commodities?
51%
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Biological lag?
- The time it takes to change numbers and quality
- Cattle, roughly 30 months from birth to slaughter
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A general trend in US livestock production is greater productivity from fewer animals. How is this accomplished with beef cattle?
- Genetics (selecting for increased carcass weight)
- Increased average daily gain which equals fewer days on feed
- Fewer DOF = increased feedlot capacity
- Increased number of imported calves from Mexico
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How are dairy producers getting more milk from fewer cows?
- Single trait selection (genetics)
- Advancements in health and nutrition
- Technology (rBST) and milking parlors
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How are poultry and swine producers getting increased production from fewer farms?
- Most are CAFOs (vertical integration)
- Greater controls (nutrition, climate, etc.) from birth through slaughter
- Economies of scale
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What is shrink?
- Animals lose a percentage of their body weight when transported
- Cattle lose roughly 6%
- Sheep, goats can lose 20%
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Six classes of nutrients?
- Water
- Carbohydrates
- Lipids (Fats)
- Protein
- Vitamins
- Minerals
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Which classes of nutrients yield energy?
- Carbohydrates
- Lipids
- Protein
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Key elements in carbohydrates and their ratio?
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Key elements in fats?
CHO
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Key elements in proteins?
NCHO
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Vitamins key elements
- CHON
- Vitamin B12
- Also may contain cobalt
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Macrominerals?
Ca Na Mg Su K Cl P
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Trace minerals?
I Se Mo Co F Fe Mn Cu Zn
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Functions of water?
- metabolic reactions
- transport of other nutrients
- maintenance of body temp
- physical shape
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Three sources of water?
- Drinking water
- Free water - ingested as a component of feed
- metabolic water - arises from metabolism in tissues
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Functions of carbs?
- source of energy for body functions
- c-skeletons for building blocks of other nutrients (vitamins, proteins, fats)
- milk synthesis
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Lipid functions
- fat is the main energy providing lipid
- contain 2.25 times more energy per pound than carbohydrates
- precursors of prostaglandins and as structural components of cells
-
Functions of minerals?
- frequently a component of vitamins, hormones
- needed for activation of certain molecules
- role in metabolism
-
Vitamins, briefly?
- Organic substances required in v. small amounts in the diet
- Not closely related in chemical formula
- Fat soluble (ADEK) and water soluble (B complex and C)
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What is greater - as fed concentrations or dry matter concentrations?
dry matter concentrations
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which is greater - AF amounts or DM amounts?
AF amounts
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Two classifications of fatty acids?
- Saturated fats (solid at room temp, no double bonds with carbon chains)
- Unsaturated fats (liquids at room temp, double bonds exist - polyunsaturated have multiple double bonds)
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Three volatile fatty acids that are primary products of ruminal fermentation?
- Acetate
- Proprionate
- Butryate
- These are short-chain fatty acids that are water soluble, so can be absorbed into the blood
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Three processes that comprise digestion?
- Prehension of food or feed
- Mechanical chewing or grinding
- Mixing with digestive acids and enzymes to chemically break down the foods
- Absorption (transport of foods across the intestinal mucosa to the blood or lymph system)
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Mechanical process of digestion
- Mastication
- Deglutition (swallowing)
- Regurgitation
- Defecation
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Features of digestive system in nonruminants (like pig)
- Mouth (prehension)
- Esophagus
- Stomach (mixing and holding)
- Small intestine (primary site of digestion and absorption)
- Large intestine (major site of water absorption)
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Pancreas is ducted into the duodenum (upper part of small intestine). What does it do?
Produces enzymes needed for digestion
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Features of digestive system in poultry
- mouth (no teeth)
- esophagus (crop, for food holding and moistening)
- stomach (proventriculus and ventriculus)
- ceca (limited function)
- large intestine
- cloaca
-
proventriculus
glandular area (adds enzymes)
-
-
Features of digestive system in horse
- huge cecum (50% of digesta)
- cecal fermentation is post-absorption
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Ruminant digestion
- Mouth (no upper incisors)
- Rumen
- Reticulum
- Omasum
- Abomasum
- Small intestine
- Cecum, large intestine
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Four parts of rumen's compound stomach?
- rumen (fermentation, absorption)
- reticulum (receives feed, mixing, regurgitation, ercutation)
- omasum (receives digesta outflow from first two compartments)
- abomasum (final holding and mixing)
-
reticulum
- honeycomb
- receives feed
- initiates mixing, regurgitation, eructation
-
omasum
- many plies
- third area of stomach receives digesta outflow of the rumen/reticulum
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Digestion of carbs in ruminants
- Cellulose - Rumen, yields VFAs, AA, B vitamins
- Starch - Rumen, yields VFAs, AA, B vitamins
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Digestion of carbs in nonruminants
- Cellulose - Cecum or large intestine (colon), yields VFAs, B vitamins, AA
- Starch - small intestine, yields glucose
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Digestion of proteins in ruminants?
- Essentially, when it comes to protein, the ruminant gets what the bugs leave behind or create
- Ruminally degraded proteins (Rumen, Microbial Cell Proteins, Small Intestine)
- Ruminally undegraded protein ("bypass protein" - Digested in Small Intestine)
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Digestion of proteins in nonruminants?
- Nonruminants get what they eat
- small intestine is the primary site of digestion and absorption in the nonruminant
- the exception is cellulose
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