• Estrus detection done 30 minutes in the morning and in the evening 
• Standing to be mounted (lordosis)
• Mounting of other cows
• Swollen vulva
• Mucus secretion

• Short period of restlessness or ram "seeking"
• Urination in the presence of the ram
• Lordosis

• Increased locomotion; tail erected or "flagging"
• Urination stance and urination in presence of stallion
• Lordosis
• "winking" of vulva

• Mild restlessness 
• Lordosis

• Surgically altered
• Vasectomized
• Gomer bull (no sperm but have testosterone)
• Androgenized cows or steers

• Chinball marker (like ball point pen; on chin of male)
• Heat-mount detectors (ex: k-mar patches)
• Marking harness (marking chalk or paint; use hot or cold to match environment)

• Device placed on tailhead region of females
• When mounted, a record will be sent via satellite to the software
• Useful to know which females you will need to breed without checking heat twice a day
• Expensive and failure of the software could be mistaken as no females in heat 

• Cost 
• Time and labor
• Ability of male to achieve intromission (act of inserting penis into vagina)

proper heat detection is critical

• Genetic improvement through increase use of superior sires
• Disease control
• Eliminates need for keeping bulls

• Time required to detect estrus
• Percent of cows in estrus during the breeding season 
• Trained personnel required
• Overuse of inferior sires

A tube-like instrument that spans the vulva and posterior vagina allowing for visual inspection of the os cervix

• commonly used in goats
• may be used in deer; however, the use of laparoscopy is becoming more popular in deer

Introduction of the spirette with a counter-clockwise rotation into the cervix (used in swine)

• gilts: inseminate 12 hours after detection of estrus
• sows: inseminate 24 hours after detection of estrus

lock up: press down on back and female becomes stiff and ready to be mounted (to detect estrus)

• Increase the productivity of genetically superior donors
• Maximize the use of valuable semen
• Transport genetics across long distances
• Production of identical offspring by embryo splitting
• Potentially valuable as research animals

• Expensive
• Labor intensive
• Requires extensive training and experience

• Superovulation
• Insemination of embryos from the donor
• Recovery of embryos from the donor
• Maintenance and storage of embryos
• Transfer of embryos to recipient females

• FSH (follicle stimulating hormone): short half-life of approx. 2 hours, used for commercial superovulation and embryo transfer (SOET) [ex: follitropin-v injection (used in cattle and obtained from porcine pituitary gland) and ovagen (obtained from ovine pituitay gland)]
• PMSG (pregnant mare serum gonadotropin; eCG): long half-life of approx. 2 to 4 days, NOT approved for use in comercial SOET in the US***, frequently used for research in Europe

• Heifers require a LOWER dosage than mature cows, as they are more sensative to the hormone
• Bos taurus cattle require a HIGHER dosage than Bos indicus cattle (Bos indicus are more sensative to the hormone)
• Bos indicus and heifers more sensative

1. Synchronization of the Recipients with the Donor
2. Superovulation of the donor female
3. Inseminate Donor with Semen from a Genetically Superior Bull
4. Recovery and Identification of Viable Embryos
5. Transfer Viable Embryos into the synchronized recipients

• Quality scores: 1- excellent, 2- good, 3- fair, 4- poor, 5- degenerate
• 1-3 may be used for immediate transfer ; scores 1-2 are frozen
• Transfers are typically done when the embryo is a morula or a blastocyst because still has an intact zona pellucida
• Morula or blastocyst: placed into uterus
• Earlier than those above: placed in oviduct surgically

• Even number of cells
• Uniform division
• Healthy zona pellucida

• Cryoprotectant to displace  water and prevent ice crystal formation or bursting og the embryo during freezing
• Sections of air are left in the straw to insulate embryo and allow for expansion of the media during freezig
• Sterile media containing components necessary for embryo survival

• Increase heard productivity by: culling non-pregnant females or rebreeding non-pregnant females
• Seperation of twins and singles in sheep for gestational nutrition
• Seperation of open and bred cattle for gestational nutrition

**If done properly, should not be many disadvantages**

• Quick
• Inexpensive (#1)
• Simple
• Accurate
• Minimal animal handling and labor
• Cannot cause abortion

• Progesterone levels measured from milk or plasma can determine whether a CL is present or not 
• BioPRYN is a commonly used commercial blood-based pregnancy test used on ruminants (BioPRYNes in mares)
• BioPRYN detects the presence of pregnancy-specific protein B (PSPB), a protein produced by the placenta [99% accurate when tested at least 28 days post-breeding]

• Rectal: (days 25-35) used when the uterus is still located before the pelvic brim and can be reached by the robe
• Abdominal: (days 35-45) used when the fetus has grown to a size in which the uterus becomes displaced over the pelvic brim 
• Ultrasounding after day 90 of gestation is pointless because fetus is too big to see
• Ultrasounding in sheep is cheap at about $0.50 per head

• Pregnancy determination prior to day 45 of gestation in sheep is used to manage the ewes plane of nutrion during pregnancy based on singletons or twins
• Ewes carrying twins will require a HIGHER plane of nutritio for optimal growth and development of the lambs
• It also reduces feed costs for ewes carrying singletons and open ewes

In females that are non-pregnant, the reproductive tract is usually located within the pelvic cavity; however, in older and large-frame cows the cervix and uterine horns may be distended over the pelvic brim into the body cavity

Determining factors (4):

• No fluid in uterus
• No membranes present upon slippage
• Thick uterine wall with a meaty texture
• Uterine tone: firm- at or near estrus / flaccid- between estrus periods

Females in this stage vary from 40 days (first time pregnancy can be detected by palpation) to 3 months of pregnancy; cervix and uterine horns are in the pelvic cavity or perhaps moving over the pelvic brim into the body cavity as stage 1 advances

Dermining factors (4):

• Fluids begin to fill the uterus and uterus is somewhat enlarged
• Presence of membranes upon slippage
• Thin uterine walls
• Placentomes are indistinct to the touch 

Females in this stage vary from 3 to 5.5 months of pregnancy; cervix is normally located on the pelvic brim with the uterine horns distended into the body cavity out of normal reach

Determining factors (3):

• Full displacement of the uterus
• Presence of placentomes
• Pulsation of middle uterine artery (fremitis- palpation of the uterine artery)

Females in this stage vary fro 5.5 months of gestation to term; cervix is at or near the pelvic brim; developing calf has achived sufficient size to be reached and palpation of calf becomes progressivelly easier as stage 3 advances

Determining Factors (3):

• Displacement of uterus but as calf grows it moes back up over the pelvic brim
• Palpation of large fetus
• Presence of placentomes 

• Cleavage
• Differentiation
• Fetal Growth

The period of fetal development beginning with fertilization and ending with parturition

• Zygote: diploid cell resulting from the fusion of the male and female pronuclei (syngamy)
• Embryo: organism in the early stages of development; not recognizable as a member of specific species

• Following fertilization, the zygote undergoes several mitotic divisions inside the zona pellucida (overall size does not change)
• The first cleavage yields a two celled embryo (each cell is called a blastomere and is a totipotent)
• Division continues rapidly until the 32-cell stage

• Species specific; a substace produced by the conceptus to prevent luteolysis
• Occurs prior to implantation/placentation

Embryo migration; beginning on day 12 the embryo must migrate 12 to 15 times per day

*proteins secreted by conceptus are not known what their function is*

• May be defined as the development of structue and function that is more specialized than the original cells or tissue
• Formation of three germ cells
• Formation of the extraembryonic membranes (placenta)
• Formation of organs
• Rapid changes in relative size

The inner cell mass (ICM) will ultimately form the fetus and is composed of three emryonic germ layers:

• Endoderm: Will develop into the digestive system, lungs, and endocryne layers
• Mesoderm: Will develop into muscle, the skeleton, cardiovasular system, and the reproductive systme
• Ectoderm:Will develop into the neverous system, skin and hair

• Yolk sac: originates from the fetal midgut; serves as a nutrient supply for the early embryo 
• Absorbs uterine secretions from the endometrium to stimulate early embryonic development
• Only exists during early gestation and eventually regresses
• Amnion: innermost membrane directly surrounding the fetus; protects the fetus from injury and provides lubrication for parturition
• Prevents lung collapse and opens the digestive tract
• Allantois: originates from the gut and forms the umbilicus; supports blood vessels and is the reservoir of nutrients and wastes for the fetus
• Chorion: outermost membrane in direct contact with the uterine tissue; it becomes vascularized by allantoic vessels and is the site of hormone production and nutrient and gas exchange

A placenta characterized by a uniform distribution of chorionic villi interdigitating with maternal endometrium throughtout the placenta

• found in sows and mares
• mares also have microscopic regions of chorionic villi known as microcotyledons

The fetal cotyledon interdigitates with the maternal caruncle to form structures known as placentomes; the majority  (at least 80%) of the blood flow for nutrient and waste exchange occurs in the placentomes 

• Found in ruminant species (cows, ewes, and goats)
• Cows: convex
• Sheep: concave

A zone or band of chorionic villi is attached to the endometrium

• Found in dogs and cats

A region or disc of chorionic villi is intimately attached to the endometrium 

• Found in humans and other primates

Six layers (least invasive) of tissue exist between fetal blood and maternal blood; the endometrial epithelium is directly apposed to the epithelium of the chorion

• Found in the sow and mare 

In certain areas, binucleate giant cells form from trophoblast cells that migrate from the chorion into the endometrial epithelium and form a syncytim; thus, there are essentially five layers between the fetal blood and maternal blood where a syncytium is formed and six layers where there is not a syncytium

• Found in ruminants

Five layers of tissue exist between the fetal blood and maternal blood; the maternal epithelium has completely eroded away and the maternal capillaries are almost directly exposed to the fetal epithelium

• Found in dogs and cats

Three layers of tissue between fetal blood and maternal blood; the chorionic epithelium is in direct contact with pools of maternal blood; the most invasive type of placenta

• Found in humans and other primates 

Diffuse : Epitheliochorial (sows and mares)

Cotyledonary : Synepitheliochorial (ruminants)

Zonary : Endotheliochorial (dogs and cats)

Dicoid : Hemochorial (humans and primates)

• Equine Chorionic Gonadotropin: maintains the primary corpus luteum and is responsible for the formation and maintenance of accessory corpora luteum
• Human Chorionc Gonadotropin: maintains the corpus luteum (cause of morning sickness)
• Progesterone: In some species (ewe, mare, and women) the placenta takes over progesterone production later in gestation
• The "progesterone block" inhibits myometrial contractions
• Estrogen: a peak of estradiol signals the pre-parturient period in some species
• Placental Lactogen: stimulates growth of the fetus and mammary glands
• Relaxin: softens connective tissue in the cervix and relaxes pelvic ligaments

• The period of development from an embryo to a fully developed fetus, prior to parturition
• More than 50% of the total fetal weight at parturition is gained during the last trimester of gestation
• Proper fetal development or programming is dependent on proper placental development during the first half of gestation