Overview of reproduction in domestic animals Flashcards
What is Progeny?
A descendent from an animal, can be used for meat production, or non-breeding functions
What is the definition of Sexual reproduction?
Fusion of the haploid genetic complements from 2
distinct gametes (ovum and spermatozoon) at fertilisation to form the genetic basis of a novel individual.
What are primary sexual characteristics?
Gonad and gamete types
What are secondary sexual characteristics?
Appearance// behaviour of the individual
What are secondary sexual characteristics?
Appearance// behaviour of the individual
What animals have sex determined after fertilisation?
reptiles, amphibians fish etc.
What is TDF?
testes determining factor
What gene helps translate TDF?
SRY gene
What are the two key cell types in the intermediate gonad?
Mesoderm and primordial germ cell
What is the male Indeterminate tubular reproductive tracts
wolfian
What is the female Indeterminate tubular reproductive tracts
Mullerian
What are the 3 different types of somatic cells in the male gonad?
Supporting cells, Endocrine cells and Connective tissue cells
What are the male and female supporting cells respectively
Sertoli cells and ovarian follicle cells
What are the male and female endocrine cells respectively?
Leydig and Thecal cells
What cells produce testosterone in a female?
the Thecal cells
What does testosterone in females then go on to stimulate?
oestrogen production which stimulates the mullerian duct
What are the two main effects of testosterone in males?
Development of secondary sex characteristics
What do sertoli cells produce?
Mullerian inhibiting factor which actively prevents the mullerian duct from forming
What is freemartinism?
When some of the blood from a male twin leaks over to female (TDF) which leads to sterility in the female
What does GnRH do?
it acts directly on anterior pituitary cells to stimulate LH and FSH release into the systemic circulation
Where is GnRH released from?
The hypothalamus
What does LH do in males?
causes the testicles to make testosterone
What two centres does a female have in the hypothalamus?
Surge and tonic
What does dioecious mean?
Animals that exist as one of two sexes
What are the two ways of determining sex?
Environmental which occurs after fertilisation and genetic which occurs at fertilisation
How is the development of the surge centre stopped in males?
Testosterone does not bind to F2 alpha, this means that it can enter the brain and be converted into estrogen which in turn prevents the surge centre form being developed
What stimulates the development of follicle cells from the pre-follicular cells?
At around 12 weeks in females, the PGC’s begin to produce oocytes by meiosis of germ cells, this stimulates the development of follicle cells
Why are oocytes not produced in males?
With the addition of TDF, pre-sertoli cells are converted into spermatogenic cords, these inhibit meiosis in germ cells
What is the effect of free-martinism on the female?
90% are sterile
What influences biological efficiency?
Reproduction efficiency, Lactation ability, Growth and development, replacement rate and longevity
When is TDF translated?
Following expression of the SRY gene
What cells does TDF act on?
Somatic cells to create an appropriate environment to support sex specific gametogenesis
What do sertoli cells become under the influence of TDF?
spermatogenic cords that then inhibit meiosis of PGC’s
What is the function of the germ cells?
They differentiate into the gametes (spermatozoa or ovum)
What is the name of the cells that produce mullerian inhibiting factor?
Sertoli cells
Explain how the production of the surge centre in females is controlled
Estrogen is produced which then binds to a protein called alpha fetal protein
which means it cannot enter the hypothalamus
In males testosterone is produced and enters the hypothalamus where it is then converted into estrogen and prevents the surge centre from being produced
