Unit 6 Flashcards
Genetics is the study of
Heredity
__________ is inherited by offspring from their parents
DNA
Animal geneticists have identified elements within genes that
can enhance animal growth, health, and the ability to utilize nutrients efficiently
Animal genetics is one of the pillars of livestock development alongside
animal health, animal nutrition and husbandry issues such as animal housing.
Animal breeding indicates
The mating of selective animals for the purpose of the enhancement of particular characteristics in subsequent generations
In animal breeding the best animals are
Used as parent animals
The objectives of animal breeding are
- increase animal yield / productivity
- improve the desirable quality of animal product
- produce disease resistant animals
Genetic improvement is based on the principle that
the products and services provided by animals are depend upon their genes and their living environment.
Methods of genetic improvement are
- breed introduction
- selection
- breeding
What is breed introduction
It’s bringing high-quality breeds of livestock into the
farm or a country
Before introducing breeds is important to
that the breeds possess higher quality characteristics than the local ones
Give the differences between local and exotic breed
Local breed Exotic breed
- mature slowly - mature early
- aren’t good producers - are good
- small animals - large animals
- adapt. - maynot adapt
- are resistant to disease. - fall victum
What are the advantages and disadvantages of breed introduction
Advantages of breed introduction
-Characteristics which are not originally present in the local breeds are introduced
- Breed introduction enhances productivity
-Crossbreeds may perform better than local breed if adapted to the
local environment
Disadvantages of introduction
- It may introduce new diseases and pests to the area
- Exotic breeds may struggle to adapt to the new area
- Exotic breeds may not reach full productivity in the new environment”
What is selection
Is the process of keeping animals with desirable traits and culling undesirable ones
What are the two types of selection
- natural selection
- artificial selection
What is natural selection
In nature Animals with desirable traits survive and reproduce while animals with undesirable traits don’t survive and reproduce
What is artificial selection
Farmers select and cule
What are the types of artificial selection
- mass selection
- progeny selection
- pedigree selection
- family selection
What is mass selection
It’s when they are selected on their own performance
- those with desired characteristics are often a large group ( large number of animals)
What is progeny selection
- when they are selected based on their progeny or offspring
What is pedigree selection
When they are selected based on the performance of their ansestors
What is family selection
- it’s when they are selected based on the performance of their family
- usually the family size is large
What are the advantages and disadvantages of selection
Advantages
- reduces the spread of diseases and parasites associated with breeding stocks
- It ensures that only the best naturally available animal is selected
Disadvantages
- is very costly in terms of time and money
- It requires expertise which may not be readily available
-It may bring about elimination of some desirable traits
of some parent stock
- no new characteristics are introduced
What is breeding
Is a method of livestock development in which inherited qualities are transferred from parent to offspring through mating
What are the two methods of breeding
- related breeding system
- in breeding
- line breeding - unrelated breeding system
- out breeding
- cross breeding
What is the simple difference between in breeding and line breeding
In breeding is more closely related animals like mother to son…
Line breeding is distantly related animals like cousin to cousin. Line breeding has a lower chance of in breeding depression
What is the simple difference between out breeding and cross breeding
Out breeding is between the same breeds while cross breeding is between the same species and different breeds
What is inbreeding and list it’s characteristics
- it’s the mating of closely related animals
- produces inbred lines
- two inbred lines can be crossbred to produce hybrid vigour
- sometimes there is in breeding depression
What is inbreeding depression
- it’s when offsprings with undesirable characteristics are produced because of recessive genes
What is line breeding and list it’s characteristics
- it’s the mating of distantly related animals
- used to preserve and strengthen the qualities of an outstanding ancestor
- has less risk when it comes to in breeding depression
- high quality commercial characters are a result of line breeding
What is outbreeding and what are it’s characteristics
- mating of unrelated animals within the same breed
- produces offspring with a greater vigor and productivity
What is cross breeding
- mating of unrelated animals with the same species but different breeds
- produces hybrid vigiour or heterosis
What are the advantages and disadvantages of related animals
Advantages
- Production of pure breeds or pure lines
- helps to concentrate and preserve
specific qualities in an animal
Disadvantages
- Reduction in vigor and performance
- often gives rise to defective animals
What are the advantages and disadvantages of unrelated animals
Advantages
- Promotes heterosis or hybrid vigor
Development of new breeds
- Grows more rapidly and is more economical to rear
- Withstand environmental variations
- More resistance against disease
Disadvantages
- Operating costs are higher than those for local breeds
- If not systematic, sizing problems and associated delivery difficulties may occur
What is artificial insemination
Artificial insemination is the process of collecting sperm cells from male
animals and depositing them into the reproductive tract of a female (vagina,
cervix or uterus)
___________is the most important reproduction technology for genetic improvement in domestic animals
Artificial insemination
Oestrous ( heat ) is shown by
- loss of appetite
-constant vocalizations - restlessness
- rubbing up against herd-mates
- lips of the vulva become redder and more moist than usual
- swelling around the vulva
- a thin mucous discharge from the vulva
-stop when mounted by other animals - mount other animals
The safe and best method of insemination in cattle is
Recto vaginal Method of insemination
What is the process of artificial insemination
Semen is collected and stored ➡️the semen straw is thawened➡️it’s loaded in a sterilised AI gun and covered with a plastic sheath➡️apply soft soap or any lubricant on the gloves left hand and insert into the RECTUM➡️is further inserted and holds the CERVIX through the rectal wall➡️the AI gun is passed
What are the advantages and disadvantages of artificial insemination
Advantages
- Reduces spread of infectious diseases such as contagious abortion and vibriosis
- It helps in maintaining the accurate breeding and parturition records
- Old, heavy and injured males can be used
Disadvantages
- Requires more time than natural services
- Improper cleaning of instruments and in sanitary conditions may lead to lower fertility
- If the bull is not properly tested, the spreading of genital diseases will be increased
What is embryo transfer
It’s when newly formed embryos prior to implantation are removed from a donor and given to another female ( recipient ) of THE SAME SPECIES
In embryo transfer donors are____________than recipients
Higher in productivity
What are the advantages and disadvantages of embryo transfer
Advantages
- Is an easier and more rapid exchange of genetic material between countries
- Involves no transport of live animals
- Reduces risks of disease transmission
- Enhances storage and expansion of rare genetic stock
Disadvantages
- The technique requires a high cost
- It requires skilled technicians
- It may be time consuming
What are the steps of embryo transfer
Cows receive a hormone- gonadotropin so that they will produce more than one egg( this is called super ovulation) ➡️ after 5 days they are artificially inseminated ➡️ after 7 days a veterinarian recovers the embryos by using floley catheter and recovery fluid( this is non surgical ) ➡️ passes through a filter and embryos are catched ➡️filtered into a lab and evaluated under a microscope( isolation and classification of embryos)➡️ frozen ( in liquid nitrogen at 37 degree or room t ) or transferred into a cow ( surgically or non surgically) ➡️pregnancy diagnosis by palpation through the rectal wall after 1 to 3 months ➡️birth ( 9 months)
What are the two types of animal identification and give some examples
Temporary - tail marking with a pen and chalk
- clipping thier hair
- dying thier fur
Permanent- branding
- ear tags
- tattooing
- ear notches
- microchips
