Nutritional effects on reproduction Flashcards
Describe the effects of nutrition on puberty
High planes of nutrition => increased growth rates and earlier puberty
Give an example of the nutritional effects on repro tract function
fat covering tests can decrease cooling
How does nutrition effect the regulation of reproduction?
Effects on hormones:
- sex hormones synthesised from cholesterol
- leptin, insulin, IGF are energy status hormones
What parts of reproduction are effected by nutrition?
Primordial follicle number determined prenatally
Puberty
Tract function
Hormones and regulation of reproduction
Cyclicity and spermatogenesis
Ovulation via repro hormones
Early embryo development and maternal recognition
Placental growth and development
Parturition
Membrane expulsion
perinatal survival
Lactation
Describe the nutritious causes of pregnancy loss in cows
Deficiencies in vit A, selenium, phosphorous, copper
Negative energy balance => lower pregnancy rates and embryo mortality
High intake of rumen-degradable protein => toxic effects of blood urea and ammonia on the embryo
Ingestion of dietary oestrogens/anti-oestrogens
Describe the use of nutrition to effect placental weight
Undernutrition through early - mid gestation => increased placental weight and increased foetus weight at term
Undernutrition in late gestation => decreased placental and foetus weight
What are the repro effects of negative energy balance?
- mobilise body reserves
- delayed return to cyclicity
- reduced circulatory glucose, insulin, IGF I
- increased non-esterified fatty acids => possible toxic effect on follicles and oocytes
- ketosis
- impaired follicle development and/or luteal function
what is the result of flushing?
Moving ewes onto good pasture or supplementary feed 2 weeks prior to tupping => increased fecundity
- increased leptin, insulin
- decreased GH and oestradiol
- increased negative feedback => increased FSH and folliculogenesis
What is the effect of selenium deficiency on female reproduction?
increased incidence of retained placenta
increased incidence of cystic ovaries
High embryonic mortality
Decreased conception rates
Increased incidence of endometritis
Birth of premature, weak or dead calves
what is the effect of molydenum fed heifers?
reduced plasma copper
later puberty
decreased peak LH conc
decreased conception
What are clinical ‘copper’ signs
what causes the clinical signs of copper deficiency in heifers?
not copper deficiency
thiomolybdate toxicity
Also causes:
- alteration in function and pathology of pit gland
- ovarian somatic cell effects (decreased steroidogenesis)
- reduced postovulatory progesterone (reduced maternal pregnancy recognition)
What is effect of preovulatory TTM infusion?
decreased progesterone => decreased interferon tau => decreased maternal recognition of pregnancy => increased pregnancy failure
what is the effect of zinc deficiency in males?
decreased libido and testicular size
What is the effect of zinc deficiency in females?
mild deficiency => decreased numbers born and birth weight and increased pregnancy toxaemia
Severe deficiency => teratogenic effects
