ANS SCI 121 test 2 lactation and ai/embryo transfer

which animals have teats

cows, sheep, goats, horses

which animals have nipples

sows and humans

the fundamental growing units of the Mammary tissue-composed of up to 200 alveoli

lobules

functional milk unit, where milk is synthesized and released

alveoli

what is alveoli made up of

alveoli cells (secretory epithelial)
myo-epithelial cells
-contracts in response to oxytocin for milk let down
capillaries

what are the characteristics of a cow teat

4 mammary glands (quarters)
4 teats
1 streak canal per teat

what are the characteristics of sheep and goat teats

2 mammary glands
2 teats
1 streak canal per teat

what are the characteristics of horse teats

4 mammary glands
2 teats
2 streak canals per teat

what are the characteristics of pig nipples

12-14 mammary glands in 2 parallel rows
8-18 nipples
2 streak canals per nipple

when does mammogenesis start

during embryonic and fetal period

what effect does estrus have on mammary growth

results in duct development and increase in cell number (hyperplasia)

what effect does pregnancy have on mammary growth

further duct development and hypertrophy-increase in size by cell enlargement

what does estrogen do

involved in lengthening and branching of ducts

what does progesterone do

duct and ductile cell multiplication
-enlargement and/or widening

what does progesterone and estrogen do together

causes lobuloalveolar development

what hormones are involved in lactogenesis

progesterone (inhibits lactogenesis) falls
prolactin
glucocorticoids
insulin or IGF-1

suckling or other teat/udder stimulation releases oxytocin from the posterior pituitary
stimulates my-epithelial cells of alveolus

oxytocin/neuroendocrine reflex

how is lactation maintained

animal must be milked or suckled
it stimulates prolactin and oxytocin release from pituitary

what happens with weaning

milk pressures on alveolus can cause cell death
alveoli collapse
alveoli and lobes disappear

what is apoptosis

programmed cell death

why do we do ai

maximize genetic improvement
reduce and control diseases-like repro and herd
continuing on the genetic line of injured or dead sires

what animals do we collect with an AV

bulls, stallions, rams, goats, and rabbits

why use an artificial vagina

keeps a standard temperature, pressure and lubrication

what does an electro-ejaculator do

its a rectal probe with a pulsating effect-ejaculation happens at a high voltage and accessory gland secretions at a low voltage

what are 3 collection techniques

electro ejaculator, massage method, and AV

when using the massage method, what happens?

rectally massage the sigmoid flexure, vesicular glands and ampullae

use of pressure too express ejaculate

how often can you collect bulls

2x daily for 2 days per week, or 3x per week

how often can you collect sheep

many times a day for several weeks

how often can you collect boars

once every other day

how often can you collect stallions

once every other day

when do you AI cows

12 hrs after heat

when do you AI sheep

last 1/2 of estrus

when do you AI sows

late 1st day of estrus or early the second day

when do you AI mares

every 2nd day during estrus

what is the point of embryo transfer?

can increase offspring from genetically superior females

what is embryo transfer

transferring an embryo of early development (morula/early blastocyst) from donor to recepient

what species is embryo transfer most successful

goats, sheep, swine, cattle, and horses

what are the steps of embryo transfer

synchronize donor and recipient using hormones
also you can super-ovulate donor using hormones to get many eggs at one time

what are 2 ways of doing embryo transfer

you have eggs, and can create embryos by ai donor
or you can collect eggs, and seminal in vetro

what is the gestation length of cows

280-285 days

what is the gestation length of ewes

147 days

what is the gestation length of mares

336 days

what is the gestation length of sows

114 days

what is the gestation length of does

150