Term
| List Four Reasons why high reproductive performance of farm animals should have a high priority |
|
Definition
1. More total offspring will be born. More may be marketed or saved to return to the breeding herd or flock. The latter allows more intensive selection.
2. More females will conceive within the scheduled breeding period. Therefore the offspring will be born in a shorter time span, will be more uniform in age, and so will be easier to manage the group
3. Feed, labor, and breeding costs should be less.
4. Fewer genetically superior animals will be culled because they didn't conceive or give birth. Selection pressure can be devoted to other production or quality traits. |
|
|
Term
| Name two roles of the male in reproduction. |
|
Definition
1. To produce amble amounts of viable sperm
2. To be willing and able to deliver semen (containing sperm) into the reproductive tract of the female in natural service or into a proper receptacle for use in artificial insemination. |
|
|
Term
| What mechanisms help ensure a lower temperature in the scrotum? Name the structures involved. |
|
Definition
1. The Cremaster muscle: is the muscle that suspends the testicle and contracts or relaxes to enhance temperature regulation
2. The Tunica dartos: is the elastic tissue and muscle fibers within the scrotal wall that contract and relax to aid in temperature regulation of the testicles.
3. The pampiniform plexus: is an arrangement of blood vessels above the testicle that aid in temperature regulation of the testicles. |
|
|
Term
| What type of environmental stress can render a dam infertile? |
|
Definition
| Environmental effects that can render a male infertile are: extreme underfeeding, especially after the animal has been well fed, a decrease in protein content, lack of vitamin A, high temperatures that result form illness or infection. |
|
|
Term
| Name the specific structures that (A) produce sperm, (B) produce testosterone and (C) provide a storage reservoir where sperm mature. |
|
Definition
(A) Testicles produce sperm. Within the testicles the seminiferous tubules produce spermatozoa.
(B) Testosterone is produced in the cells of leydig or interstitial cells. Their production of testosterone is controlled by a hormone of the anterior pituitary, leutinizing hormone.
(C) The Epididymis is a site of sperm storage and maturation. In the testicles the sperm undergoes a series of maturation processes |
|
|
Term
| Name the structures that carry sperm from the testicles to the urethra upon ejaculation |
|
Definition
| The Pathway for sperm is: Seminiferous tubules---> Rete testis---> Epididymis ---> Vas deferens --->Urethra |
|
|
Term
| Name the accessory sex glands of the male and three functions they perform. |
|
Definition
The accessory sex glands of the male are: The Ampulla, Seminal Vesicles, Prostate Gland, and the Cowper's glands.
The accessory sex glands:
-add volume to the ejaculate and enhance survival and movement of the suspended sperm by producing nutrients and electrolytes
-The fluids contain sodium chloride, potassium chloride, nitrogen, citric acid, fructose, and several vitamins, which may be utilized by the sperm cells for energy and metabolic processes.
-Fluids also serve as lubricants in the mating process. |
|
|
Term
| How does the reproductive structure of the stallion differ from that of the bull, boar, or ram? |
|
Definition
|
|
Term
| Name two reasons for castration of male meat animals. At what age is castration typically performed? |
|
Definition
| One reason for castrating is that castrates are easier to manage than intact males; without sex libido they are calmer in the feedlot. Another reason for castration is that it helps ensure that the meat form males will have no sex related odor, especially in the case of the swine. Castration should occur as early as possible because stress is usually less at a young age. As soon as the testicles have descended into the scrotum. |
|
|
Term
| What should a breeder do when numerous cryptorchids occur in the herd or flock? |
|
Definition
| Those that are not sterile should not be used for breeding. |
|
|
Term
| Name the major structures of the female reproductive tract |
|
Definition
| The ovaries, oviducts, horns of the uterus, body of the uterus, cervix, vagina, vestibule, and vulva. |
|
|
Term
| Describe the appearance of Graafian follicle. how does this structure differ in appearance from the corpus luteum? |
|
Definition
|
|
Term
| Name the functions of the fallopian tubes (oviducts) |
|
Definition
| Oviducts connect the tip of the uterine horn with the respective ovary. The oviducts provide a passageway for both the sperm en route to the ovum and the resulting fertilized ovum or zygote as it travels to the uterus. |
|
|
Term
| Describe how the uterus and uterine horns differ in shape between sows, cows, and mares. |
|
Definition
In the Sow, the body of the uterus is quite small, but the horns are of considerable length to accommodate as many as 8-10 fetal pigs in each horn.
-in the cow: the uterine body extends only a few inches beyond the tip of the cervix, then joins the two well-developed horns.
-the mare: has rather short uterine horns but a well developed uterine body. |
|
|
Term
| Name the innermost layer of the uterus. |
|
Definition
| The endometrium is the innermost lay of the uterus. |
|
|
Term
| Describe the appearance of the cervix. What are its functions? |
|
Definition
The cervix of a mare: consists of numerous folds of muscle layers that, although restrictive, are rather easy to manipulate during insemination.
The cervix of the cow or ewe: consists of several ridges, or interlocking rings, which during insemination must be rasped through the rectal wall in order to guide the inseminating rod through.
The cervix of the sow: is less difficult to penetrate, although its corkscrew-like muscle arrangement is somewhat restrictive.
The cervix secrets considerable amounts of thin mucus during its dilated condition at estrus. A thicker mucus is produced upon pregnancy and provides a hardened seal or plug that blocks access to the uterus. During parturition, the cervix must dilate and stretch to allow delivery of the newborn. |
|
|
Term
| What role(s) do the vagina perform? |
|
Definition
| It receives the penis during parturition and also provides a passageway for birth of the fetus. |
|
|
Term
| Where are ova produced? What hormone causes their production? What hormone is most responsible for their release at time of ovulation? |
|
Definition
| Ova are produced on the ovary. Estrogen causes their reproduction. The luteinizing hormone is responsible for their release at the time of ovulation. |
|
|
Term
| What major horomone is produced by the cells of the Graafian follicle? What effects does this hormone have upon the female? |
|
Definition
| The cells of the Graafian follicle produce progesterone. Progesterone aids in maintaining pregnancy by preventing further estrus during pregnancy. It also increases the development of the alveolar structures in the mammary gland which produce milk. |
|
|
Term
| What is the principal hormone of the corpus luteum? What effect does it have on the female that is (a) non-pregnant and (B) pregnant? |
|
Definition
|
|
Term
| What is the role of prostraglandin and where is it produced? |
|
Definition
|
|
Term
| Name the phases of the estrous cycle |
|
Definition
|
|
Term
| What principle hormones are involve din bringing about successful parturition. Name the stages of part urition. |
|
Definition
|
|
Term
| Name two differences in the male reproductive system of the bird as compared to the mammal. |
|
Definition
|
|
Term
| Why will artifical insemination of most farm animal species become increasingly popular. |
|
Definition
|
|
Term
| What are the advantages of multiple ovulation, estrus synchronization, embryo transplantation and embryo sexing? |
|
Definition
|
|
