Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
96 Cards in this Set
- Front
- Back
|
The Reproductive Symphony |
|
|
|
Factors affecting the onset of puberty |
genetic + hormonal + nutritional + environmental l l \/ puberty |
|
|
Measures of Puberty |
libido + sperm production (spermatogenesis) + sex organ development l l \/ puberty |
|
|
Hormones |
- hormones are chemical mediators produced by the endocrine glands that regulate the function of target organs in another part of the body |
|
|
Reproductive hormones are produced by the: |
- pineal gland (photoperiod) - hypothalmus - pituitary gland - ovaries - testes - placenta |
|
|
Hormones regulate all of the critical steps in successful reproduction in both sexes, including: |
- puberty - ovulation - transport of sperm and ova |
|
|
In the female reproductive tract hormones regulate: |
- maintenance of pregnancy - parturition |
|
|
In the male, hormones regulate |
- puberty - sperm production - development and maintenance of accessory sex glands - secondary sex characteristics - libido |
|
|
FSH (follicle stimulation hormone) |
1. initiated follicular growth 2. influence spermatogenesis - from anterior pituitary |
|
|
LH (luteinizing hormone) |
1. stimulates growth of tissues in gonads which secrete hormones 2. acts with FSH to cause ovulation 3. causes corpus luteum formation - from anterior pituitary |
|
|
Prolactin |
1. ovary: maintains functional capacity of the corpus luteum 2. mammary gland: stimulates formation of milk in alveoli 3. causes broodiness in birds - from anterior pituitary |
|
|
Oxytocin |
1. uterus: stimulates contraction (birth, avian egg laying) 2. mammary gland: initiates let-down of milk into ducts and cisterns - from posterior pituitary |
|
|
Estrogen |
1. stimulates growth of accessory reproductive organs and secondary sex characteristics 2. induces estrus (heat) 3. mammary gland: stimulates development of the duct system - from ovary |
|
|
Progesterone |
1. inhibits release of FSH & LH 2. prepares uterus for implantation 3. maintains pregnancy 4. mammary gland: develops alveolar system - from ovary |
|
|
Relaxin |
1. relaxes pubic bones and cervix (birth) - from cervix |
|
|
Angrogen (testerone) |
1. stimulates sexual desire 2. stimulates growth of accessory reproductive organs and secondary sex characteristics - from testes |
|
|
Gonadotrophin-releasing hormone (GnRH) |
1. causes release of FSH and LH from anterior pituitary - from hypothalmus |
|
|
Prostaglandin F2 alpha |
1. causes regression of corpus luteum in sheep, cattle and swine - from uterus |
|
|
Reproduction - Female |
successful livestock production depends upon obtaining the optimum number of viable offspring per year from each producing female |
|
|
Beef and Dairy Cattle |
- giving birth to one offspring per pregnancy - efficient reproduction means obtaining a calf each year from as many cows as possible |
|
|
Sheep and Goats |
- obtaining more than one lambing/kidding per year, if possible, or - at least two lambs/kids per ewe per year |
|
|
Swine |
- two litters per year - having at least 8-10 piglets weaned per farrowing |
|
|
Poultry (laying hens) |
- the highest number of eggs per hen per year - or minimally 285 eggs per year |
|
|
For high reproductive efficiency, farm animals should: |
- reach puberty at an early age - possess high levels of fertility and/or fecundity - raise a high proportion of their offspring |
|
|
Cattle: - Gestation Length in Days - Usual Number of Offspring Born |
- 283 - 1 |
|
|
Ewe - Gestation Length in Days - Usual Number of Offspring Born |
- 150 - 1 to 3 |
|
|
Mare
- Gestation Length in Days - Usual Number of Offspring Born |
- 346 - 1 |
|
|
Sow - Gestation Length in Days - Usual Number of Offspring Born |
- 115 - 6 to 14 |
|
|
Doe (goat) - Gestation Length in Days - Usual Number of Offspring Born |
- 150 - 2 to 3 |
|
|
Doe (rabbit) - Gestation Length in Days - Usual Number of Offspring Born |
- 31 - 4 to 8 |
|
|
Jill (mink) - Gestation Length in Days - Usual Number of Offspring Born |
- 50 - 4 |
|
|
Queen - Gestation Length in Days - Usual Number of Offspring Born |
- 52 - 4 |
|
|
Bitch - Gestation Length in Days - Usual Number of Offspring Born |
- 60 - 7 |
|
|
Ovary |
|
|
|
Estrous Cycle |
- estrous cycle = anestrus + estrus - seasonally polyestrous * ewe * doe * mare - polyestrous * cow * sow |
|
|
The basic mechanism of the estrual and ovulatory cycles of the mamalian female |
|
|
|
Cow in Estrus (heat) |
- primary sign - being mounted by other cows
- possible mounting of other cows - mucus discharge form vaginal area, and smearing on tail, thighs, flanks and perineal region - swelling and reddening of the vulva - bellowing, restlessness, and trailing - rubbed tail head hair and dirty flanks - sniffing genitalia - head rising and lip curling |
|
|
Cow - average days in cycle - duration of heat (hrs) - time of ovulation - suggested time of mating |
- 21 - 12 to 18 - 12 to 15 hr after estrus - 4 to 8 hr before end of estrus |
|
|
Sow - average days in cycle - duration of heat (hrs) - time of ovulation - suggested time of mating |
- 21
- 48 to 72 - 18 to 40 hr after start of estrus - 24 hr after start of estrus |
|
|
Ewe - average days in cycle - duration of heat (hrs) - time of ovulation - suggested time of mating |
- 17 - 24 to 36 - 18 to 26 hr after start of estrus - 12 to 18 hr after start of estrus |
|
|
Doe - average days in cycle - duration of heat (hrs) - time of ovulation - suggested time of mating |
- 21 - 34 to 39 - 9 to 19 hr after start of estrus - 12 to 18 hr after start of estrus |
|
|
Mare - average days in cycle - duration of heat (hrs) - time of ovulation - suggested time of mating |
- 22 - 4 to 8 (days) - 24 to 48 hrs after start of estrus - Alternate days during estrus |
|
|
Reproductive Tract of Ram |
On tablet |
|
|
Primary Sperm Abnormalities: Head |
- pyriform or pear shaped - round - elongated or slender - microcephalic or small - macrocephalic or giant - double or twin - abnormal acrosome |
|
|
Primary Sperm Abnormalities: Midpiece |
- bent or kinked at right angle - twin or double - enlarged or swollen - off center attachment |
|
|
Primary Sperm Abnormalities: Tail |
- coiled or curled - double tail - bent tail |
|
|
Pathway for sperm |
semininferous tubules ----> rete testis -----> epididymis -----> vas deferens -----> urethra -----> uretha within penis
|
|
|
What is semen? |
sperm cells + fluids from ampulla, seminal vesicles, prostate, and cowper's gland |
|
|
Purposes of accessory gland fluids |
- add volume to the ejaculate - enhance sperm survival - enhance sperm movement - provision of nutrients for sperm - provisions of electrolytes for sperm - lubrication for mating process - neutralization of urinary acid residues in the urethra |
|
|
Accessory gland fluids contain |
- sodium chloride - potassium chloride - nitrogen - citric acid - fructose - several vitamins |
|
|
Implantation |
- fertilized ovum moves down the fallopian tube (oviduct) to the uterus - zygote survives on yolk and uterine milk (uterine secretions until contact is made between the maternal and fetal membranes) - this initial contact is called implantation or nidation |
|
|
Implantation continued |
- after implantation, the developing embryo to fetus obtains nourishment from it's dam. - implantation is a gradual process * ewe 10-18 days * sow 12-24 days *cow 12-30 days *mare 30-60 days |
|
|
Types of abnormal implantations: |
- ovarian: young seldom survive to full term - tubal: young occasionally survive to birth - abdominal: young do not survive to full term |
|
|
3 primary placental membrances |
1. amnion: innermost 2. allantois: middle 3. chorion: outermost |
|
|
Placentation |
- each embryo usually have their own set of membranes - two individual embryos may fuse, resulting in a common blood supply - twins in cattle have common membranes and a common blood supply * having common membranes and blood supple results (90% of the time) in Freemartin condition of heifer (freemartinism) |
|
|
Placentation |
- intrauterine migration: distribution of young embryos equally in uterine horns in sow, bitch, and other litter bearing animals. |
|
|
Placentation continued |
- early in gestation, young embryos develop membranes to provide for protection and nourishment - these membranes are called feral membranes - amnion: the innermost membrane which surrounds the embryo/fetus * developing fetus is suspended in this fluid |
|
|
Placentation continued
|
- chorion: the outermost layer of fetal membranes that makes contact with the maternal uterine tissue - ruminants are cotyledonary type of chorionic attachment - contacts are made only at certain points in the uterus called caruncles |
|
|
Placentation continued
|
- sow and mare have a diffuse type of chorionic attachment * contact is made over most of the chorion surface with the uterus - outer portion of allantois is fused with the chorion and the inner layer with the amnion - the formed sac or space is filled with allantoic fluid that accumulates waster from the developing fetus |
|
|
Placentation continued
|
- placenta: is formed by the fusion of the chorion and the uterine mucosa |
|
|
Function of the Placenta |
1. transmission of nutrients from dam to young 2. transmission of wastes form you got dam 3. protection of young from shock and adhesion by means of amniotic fluid 4. prevention of bacteria and other large molecular substances from dam to young 5. the secretion of certain hormones; HCG (woman) and PMSG (mare) |
|
|
Placental Barrier |
1. prevents large molecules such as antibodies and large amounts of fat soluble vitamins form passing in large amounts from mother to young 2. virues that are small enought to prenetrate the placental barrier can cause defects in young * developing young are susceptible to viral infection because they have not produced their own antibodies 3. certian other chemical substances int he dams reation penetrate the placental barrier and may bause congenital defects |
|
|
Artificial Insemination |
- the deposition of spermatozoa in the female genitalia by artificial rather than by natural means - A.I. reported to be used as early as 3222 A.D. in horses - A.I. in dogs initially conducted in 1780 - A.I. first used commercially in the United Stated in 1938, primarily in dairy cattle |
|
|
Artificial Insemination continued |
- all turkey in the U.S. are bred by A.I., which started in the 1970's, due to large breasted 'toms' - over 70+% of U.S. dairy cows and heifers are bred artificially - over 5 & 10% of U.S. beef cattle, sheep, and horses are bred by A.I. today |
|
|
The principal advantages of A.I. are: |
1. more rapid genetic improvements through the use of superior sires 2. reduction or elimination of cost and risk of maintaining a shire for a small herd or flock; and 3. reduced risk of spreading certain reproductive diseases |
|
|
Other advantages of A.I. |
- extend the usefulness of outstanding sires in order to maximize genetic improvement - limited life-time breeding soundness of farm animal sires - for example, in an A.I. program, bulls can produce 200-400 unit of semen/ejaculate; at 3 to 4 ejaculates per week |
|
|
Other advantages of A.I. continued |
- if frozen semen stored, hundreds of thousand of calves can be produced by a single sire'- many calves can be produced years after the sire is dead - generally it takes approximately 1.5 units of semen to produce each A.I.'ed calf born in the U.S. |
|
|
Semen Collection |
Artificial Vagina (aka A.V.): the training of the male is most crucial for success in utilizing this semen collection method Electro-Ejaculator: the use of very low voltage delivered to the male via the rectum to bring about ejaculation for semen collection |
|
|
Semen Collection continued
|
Vaginal Reclamation: the retrieval of semen from the vagina of the female used for the collection of semen. The male is allowed to breed the female naturally with this process. Straws, stainless steed spoons, pipettes, etc. can be utilized. Manual Massage: this method requires that the handlers place his/her arm and hand inside the sire's colo-rectal area and the massaging of the male's ampullae, and in turn bring about the release (ejaculation) of the semen |
|
|
Cryogenic semen storage |
- each unit should contain 10 million motile normal spermatozoa - semen can be used 'fresh' and if properly handled can remain viable from 1 to 2 days from collection. If semen is to be used 'fresh' it must be maintained exactly at 40 F. - Semen is frozen in liquid nitrogen |
|
|
Cryogenic semen storage continued
|
- stored in glass vials or plastic straws - cryogenically stored semen can last for years, and long after the sire has been deceased - poultry semen does not stand freezing and thawing well so is generally used withing two hours after collection - extended boar semen provided optimal conception rates at 72 hours |
|
|
Semen Evaluation Criteria |
1. color 2. volume 3. motility 4. sperm concentration (density) 5. abnormalities 6. pH |
|
|
Semen Extenders - Diluents |
1. milk 2. egg yolk 3. chemical buffers 4. antibiotics 5. glycerol |
|
|
Estrus detection is important in an A.I. program |
Standing heat: female stands still when mounted by male or another female Estrus: check twice daily, both AM and PM Observation: watch open females for at least 30 minutes to detect standing heat. |
|
|
Signs of estrus |
- restlessness
- cows attempting to mount other cows - clear mucus discharge from vagina - sheep & goats are best checked utilizing a sterilized male, equipped w/ a breast marking harness - gilts a&sows in head stand rigid w/ ears erect when hands are placed firmly on their backs * the vulva is usually red & swollen * presence of boar & the resulting sounds & odors can help detect heat in swine * female will attempt to locate board |
|
|
Signs of estrus in the mare |
1. tail elevation 2. contractions of vulva (aka winking) 4. frequent urination |
|
|
Signs of estrus- additional considerations |
- proper time of insemination is critical - insemination time should be close to ovulation time as much as possible - a female detected in estrus in AM should be inseminated in PM - a female detected in estrus in PM should be inseminated the next morning |
|
|
Teaser Males |
- a teaser is a vasectomized male so he is sexually active but does not ejaculate fertile sperm - teasers are used to identify females in estrus (heat) which can be ready for A.I. - teasers have all of the risks and management issues of keeping intact males |
|
|
Most common form of teasers |
- vasectomy - epidectomy - gomer |
|
|
Estrous Synchronization |
- is controlling or manipulating the 'estrous' cycle so that females express 'estrus' as approximately the same time
- is a useful part of an A.I. program, because heat checking and breeding animals under extensive management conditions is time-consuming and expensive - is also an important and essential tool in embryo transfer programs |
|
|
Estrous Synchronization tools
|
1. prostaglandin or prostaglandin F2a (PGF2a) - a naturally occurring fatty acid that has a marked effect on reproductive systems. Prostaglandin destroys the CL, or source of progesterone, helping bring animals into head 2. MGA and Prostaglandin - MGA (melengestrol acetate) a feed additive the suppresses 'estrus' in heifers and is widely used in the feedlot industry |
|
|
Estrous Synchronization tools
|
3. syncro-mate 'B' - a combination or 'estradiol' and 'norgestomet'. Injection and subcutaneous implant system 4.CIDR - progesterone vaginal insert for estrous synchronizaton |
|
|
Teaser Animals |
Young bulls: young bulls approaching puberty will be sexually active and follow and attempt to mount cows in estrus |
|
|
Teaser Animals
|
Peeudohermaphrodites & Nymphomaniacs: male pseudohermaphrodies have tests but appear as females exteriorly. The testes produce testosterone, & libido is therefore present. They are good teasers because of the lack of male external genitalia but are rare animals to find.
* the nymphomaniac or sex crazy females results from a high level or estrogen, which usually is derived from a cystic follicle. These highly excitable animals are also mounted by other animals because they too are in constant or intermittent estrus |
|
|
Teaser Animals |
Treated Steers: steers may be treated w/ testosterone to bring about libido. An injection of 100 to 500 mg. testosterone in oil should result in increased libido for several weeks duration Treated Females: overiectomized females may be injected w/ an estrogen to increase libido. They in turn will mount cows in estrus |
|
|
Teaser Animals |
Vasectomy (tube removal): vasectomy or vasoligation is probably the most common method of sterilizing the male. The vasa deferentia are exposed and a section removed to interrupt passage of sperm |
|
|
Teaser Animals |
Epididymal Resection: the tail of the epididymis may be removed with similar simplicity and response as in vasectomy, aka "Russian castration" or "epidectomy" Epididymal Transection: the trail of the epididyis may be cut in several areas to interrupt sperm passage Epididymal occlusion: injection of sclerotherapeutic (hard-healing) agents into the tail of the epididymis occluedes passes as in transection |
|
|
Teaser Animals |
Preputial Closure and Fistulation: the prepuce may be sutured closed & a small fistula formed about 2 inches posterior to the normal orifice on the ventral surface for urination. Vasectomy or epididymal removal usually accompanies the closure |
|
|
Teaser Animals |
Preputial Restriction: a restriction can be formed in the preputial canal to restricts extension of the penis by passing a suture of umbilical tape in the skin of the prepuce about 3/4 inches posterior to the opening in a purse-string suture manner. This may be removed later for natural use of the bull. The animal may be used immediately w/out impairment or libido
|
|
|
Teaser Animals |
Penile Retraction & Fixation: there are several ways this may be done, but the most common is exposing & anchoring the penis w/ wire sutures anterior to the scrotum or by anchoring the penis in the escutcheon, halfway between the scrotum & anus. The penis is restricted from extension upon erection. Complications arise from occlusions of he urethra by sutures & tearing of adhesion to release the restriction |
|
|
Teaser Animals |
Penile Deviation: a very popular method currently is a displacement of the penis to one side so that intro mission is absent due to misalignment. The penis is isolated by mid ventral incision& an incision around the prepuce. The penis & prepuce are realigned about 45 degrees to one side & the incision closed |
|
|
Teaser Animals |
Phallectomy or Penectomy: removal of a portion of the penis has been used in developing teaser bulls. The shortening prevents intromission. The penis may be removed with anterior or posterior to the scrotum. A new urethral orifice is formed at the point of the removal |
|
|
Teaser Animals |
Peno-O-Block: this is a device made of a plastic tube about 1 inch in diameter & 6 inches long & a stainless steel pen & washers. The tube is placed in the prepuce until the distal end is 2 to 4 inches from the office & anchored there by piercing the sheath w/ a trochar and cannula & anchoring the stainless steel pin through the sheath & tube. The prepuce is held open for urination but the pin prevents extension of the penis |
|
|
Teaser Animals |
Ring restriction: an ordinary bill ring may be passed through the sheath & prepuce to clock extension of the penis. Bypassing the ring is possible, so this is not a desirable method |
|
|
Teaser Animals |
Aprons: aprons covering the sheath & area of the penile extension may be used on animals under close observation. W/ activity the apron may shift, allowing mating. Sanitation is a problem & the penis becomes chaffed & sore. |
|
|
Teaser Animals |
Gomer Bulls: the term gomer is a readily accepted term for an altered bull that cannot make sexual contact w/ the cow. The origin of the term was described by Wayne Clews, a rancher in Canada, as a name given detector bull by the children of one of his customer. It just seemed to catch on, & today it is commonly used |
