Nutritional effects on reproduction Flashcards
True or false:
The primordial follicle number is determined prenatally and is influenced by nutrition.
True
True or false:
High planes of nutrition give increased growth rates and generally earlier puberty
true
What effect does insulin have on the reproductive system?
Direct action on antral follicle growth and steroid production
Regulator of circulatory IGF (via effects on GH receptors)
What effect does IGF have on the reproductive system?
Enhances ovarian action of gonadotrophins (IGF I)
Direct effect on follicle growth and steroidogenesis (IGF I and II)
What effect does leptin have on the reproductive system?
At physiological levels inhibits oestradiol secretion and increases folliculogenesis
How can nutrition cause abortions in cattle?
Deficiencies in vitamin A, selenium, phosphorous, copper
Negative energy balance (loss of condition reduces fertility and a severe energy deficit can cause embryo mortality)
High intakes of rumen-degradable protein can have toxic effects of blood urea or ammonia on the embryo
Ingestion of dietary oestrogens/anti-oestrogens eg. pine needles
How can we use nutrition to increase foetal weight at term?
In sheep if you restrict grazing early-mid gestation and then increase feed it will increase placental weight and foetal weight at term
What is flushing in terms of nutrition?
Two weeks prior to tupping moving ewes onto good pasture (lupins and glucose)to raise the plane of nutrition and this will increase number of lambs per ewe
How does flushing work?
By increasing insulin and leptin causing a transient Transient increase in FSH, decreased oestradiol (increased negative feedback gives increased FSH and increased Folliculogenesis)
What will a selenium deficiency during pregnancy cause?
Increased incidence of retained placenta Increased incidence of cystic ovaries High embryonic mortality (3-4 weeks post conception) Decreased conception rates Increased incidence of endometritis Birth of premature, weak or dead calves
What is the effect of copper deficiency on reproduction?
Copper deficiency causes a delay in puberty:
Failure to display oestrus behaviour
Irregular oestrus, ultimately anoestrus
Reduced conception rates
Reduced peak ovulatory LH
Reduced feed intake and conversion efficiency
Hair pigmentation and texture (ginger/spectacles)
Although it is not actually a copper deficiency but it is a thiomolybdate toxicity
Excess thiomolybdates have also been found to cause….
Gross alterations in pathology and function of pituitary
Ovarian somatic cells effects (decreased steroidogenesis)
Reduced postovulatory progesterone (reduced maternal pregnancy recognition)
What effect does zinc deficiency have on the male reproductive tract?
Zinc has major roles in DNA and Protein replication essential for spermatogenesis . Deficiency gives decreased libido and testicular size
What effect does zinc deficiency have on the female reproductive tract?
In female mild deficiency decreases numbers born, birth weight and leads to increased pregnancy toxaemia (anorexia)
Severe deficiency in early pregnancy leads to teratogenic effects
What are the reproductive symptoms of iodine deficiency?
Lowered conception rates
Irregular oestrus, anoestrus
Retained placenta
Abortions/ Still births, birth of weak and/or hairless calves if deficiency is in the last trimester
Cystic ovaries
In male decreased libido and semen quality
Thyroid hormones produce lung surfactants – decreased newborn viability and Increased Post natal susceptibility to Hypothermia
