- - AGRICULTURE CORE CURRICULUM - - (CLF3000) Advanced Core Cluster: ANIMAL SCIENCE (CLF3250) Unit Title: LIVESTOCK BREEDING AND GENETICS ____________________________________________________________________________ (CLF3257) Topic: ARTIFICIAL Time Year(s) INSEMINATION 2 hours 3 / 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson, the student will be able to: Learning Outcome #: (D-12) - List important factors to consider in a bull fertility test. (D-13) - Explain the process of artificial insemination and its impact on the gene pool in modern livestock. Special Materials and Equipment: VEP Filmstrips; "Artificial Insemination of Beef and Dairy Cattle", "Introduction to Equine A.I.", "Inseminating and Diagnosing Pregnancy", "Semen Collection and Evaluation", and "Teasing and Rectal Palpation", and Supplemental Worksheet #3. References: Ensminger, M.E. (1983). THE STOCKMAN'S HANDBOOK (6th ed.). A.I. MANAGEMENT MANUAL. (1983). American Breeders Service. Hafez, E.S. (1974). REPRODUCTION IN FARM ANIMALS. Evaluation: Quiz by instructor and completion of Supplemental Worksheet #3. TOPIC PRESENTATION: ARTIFICIAL INSEMINATION A. Fertility Testing is an important step in evaluating males to be kept for breeding. Fertility testing is indispensable in the area of artificial insemination since a bull may be worth thousands of dollars and still produce progeny long after his death (because the semen is stored). Fertility Testing is the process of evaluating the bull's ability to reproduce. 1. Factors to consider: a. Libido (sex drive) - This is especially important in bulls kept for natural breeding since some bulls are more active breeders than others. b. Scrotal circumference - This is an observable, measurable characteristic that indicates fertility. In general, the greater the scrotal circumference, the greater the sperm production, hence increased fertility. c. Semen evaluation - This is the most important factor in fertility testing. Semen is evaluated for: 1) appearance - a uniform opaque appearance indicates a high sperm concentration. A sample which appears to be translucent contains fewer sperm cells. Semen with a curdy appearance should not be used as this indicates inflammation. 2) volume - may vary depending on the age of the bull. Younger bulls produce a smaller volume of semen which is not a negative factor as long as the concentration of semen is good. d. Motility and live cells - 1) It must be evaluated under a microscope at 400X. 2) Most semen should contain 70 percent or more motile cells at 40 degrees Centigrade. e. Concentration - 1) Determined by the number of sperm per milliliter of semen. 2) This is probably the most important indicator of fertility, except with bulls, in which scrotal circumference is the determinant. f. Morphology - 1) The proportion of abnormal sperm should not exceed 20 percent. 2) Most males do, however, produce some abnormal sperm. B. Semen Collection 1. Methods: a. Artificial Vagina - 1) Consists of an outer tube or casing which is constructed of heavy rubber or plastic, and an inner tube or lining of thin rubber. The space between the two tubes is filled with warm water, which maintains the collected sperm at a constant temperature, neither too hot or too cold. 2) One end of the apparatus is open to allow the entrance of the penis and the other end is attached to a glass tube or beaker to receive the ejaculated semen. 3) This is the most commonly used device for collecting semen. b. Electric Stimulation - 1) Electro-ejaculator apparatuses introduce a weak alternating current to the sacral and pelvic nerves via electrodes placed in the rectum until erection and ejaculation occur. 2) It is used on all farm animals except boars and horses. 3) It is used effectively on bulls that cannot mount due to leg injuries. c. Rectal Massage - 1) Massage of the ampullae and the collection of the ejaculate (semen) in a funnel leading to a glass tube. 2) It is used occasionally in bulls and stallions. 3) This method is used with males unwilling or unable to mount. C. Semen Preparation 1. Storage and shipment: a. It may be kept at room temperature if it is to be used within two hours of collection. b. If the semen will be put into long-term storage, glycerol is semen, which is gradually cooled and frozen a temperature below zero. 2. Semen extenders: a. Extenders are added to semen because - 1) they provide extra needed volume, and 2) they exert a beneficial effect on the sperm. b. Some examples of extenders are listed below - 1) egg yolk - phosphate, used in bull, ram, and stallion semen; 2) egg yolk - citrate, used in bull and ram semen; 3) homogenized whole milk - used in bull, ram, and boar semen; and 4) glycine-containing diluents - used in boar semen. c. Some extenders contain antibiotics to control bacteria and contamination. D. Artificial Insemination 1. Definition: The deposition of sperm in the female genitalia by artificial means. 2. The history of A.I.: a. It may have been used as far back as 1322, at which time an Arab chieftan used artificial methods to impregnate a prized mare. b. The first scientific research relative to A.I. in domestic animals was conducted with dogs by the Italian physiologist Lazarro Spallanzani. c. It was first used commercially in cattle in the U.S. in 1938. d. Currently A.I. is most widely practiced with dairy and beef animals. It is also used with horses; however there are many breed regulations which effect A.I. use in the horse industry. 3. The process of A.I.: a. Equipment needed - 1) Liquid nitrogen tank, a) used to store semen straws at -385 degrees Fahrenheit, (-196 degrees Centigrade), and b) a semen straw contains a single dose of semen. 2) Inseminating syringe, a) made from stainless steel, and b) used to place semen in the reproductive tract of the cow. 3) Semen thawing unit, used for thawing the frozen semen before insemination. b. Inseminating the cow - 1) Restraint, must be gentle and not overly stressful to the animal; a halter or neck squeeze is most often used. 2) Preparation of semen, the A.I. technician knows the proper sanitary methods for thawing semen and placing it in the insemination syringe. 3) Palpation, the A.I. technician will put his/her arm inside the cow's rectum, through the rectal wall gently grasps the cow's cervix (A.I.technicians take special classes to become certified) in his her hand. 4) Insemination, after the technician has the cervix, she/he inserts the inseminating syringe into the cow's vagina. The syringe is passed through the vagina and about half way through the cervix at this point the semen is ejected into the reproductive tract of the cow. 4. Advantages of Using Artificial Insemination: a. It increases the use of outstanding sires so that - 1) breeders can use the best bulls by purchasing semen through breeder's catalogs. 2) there is a selection advantage by using A.I. with top bulls. 3) thousands of offspring can come from one sire,which would be impossible using natural breeding (unlike the small number per cow when embryo transfer is used). b. It controls diseases by - assuring use of semen from healthy bulls, thus reducing the spread of venereal diseases such as vibriosis, which causes cows to abort their calves. c. It creates large families of animals, which provides uniformity and gives a better basis for a constructive breeding program. d. It overcomes physical handicaps by - 1) mating animals of different sizes for example, a) using mature sires on first calf heifers, and b) using crippled sires unable to perform a natural service. e. It can "prove" more sires, as more bulls can have their genetic worth determined at an earlier age so that they can be put into use earlier and serve a longer period of usefulness as a sire. f. It allows more livestock producers access to high quality bulls. (Semen can be shipped anywhere in the world!) __________________________________________________________ ACTIVITY: 1. Use VEP filmstrip "Artificial Insemination in Beef and Dairy Cattle". 2. Complete Supplemental Worksheet #3. 3. Invite an A.I. Technician to speak to the class about the process, equipment, the profession, and hopefully provided a demonstration. __________________________________________________________ Supplemental Worksheet #3 ARTIFICIAL INSEMINATION NAME__________________________________ DATE__________________________________ PER.__________________________________ 1. What is fertility testing? 2. How is fertility testing related to artificial insemination? 3. List the important factors to consider in a bull fertility test: 4. What does "morphology" mean? 5. Define the artificial insemination and compare it to the term natural service or breeding. 6. Describe the process of artificial insemination: 7. Why is it important not to stress the cow before insemination? 8. Describe the impact that artificial insemination can have on the animal industry: 5/2/90sg #%&C