Reproductive Physiology and Endocrinology: Understanding Puberty in Animals - Prof. Joel V, Study notes of Animal Biology

Download Reproductive Physiology and Endocrinology: Understanding Puberty in Animals - Prof. Joel V and more Study notes Animal Biology in PDF only on Docsity! ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 37 Puberty 1) Prenatal development __________________________________________________________________________ Male (Fig 6-1) _____________________________________________________________________ Testosterone crosses blood brain barrier, converted to estrogen _________________________________________________________________ Female ____________________________________________________________________ Estrogen bound to alpha-fetoprotein, prevents entry into brain ____________________________________________________________________ Leads to differences in postnatal LH secretion patterns (Fig 6-2) Lack of surge center in male ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 38 2) Female Definition Puberty ____________________________________________________________________ First ovulation may not be accompanied by estrus ____________________________________________________________________ Determine by evaluating ovaries (rectal palpation, ultrasonography, laproscope) _______________________________________________________________ _____________________________________________________________________ Dependent on several factors: threshold body size, dictated by nutrition 3) Male Definition Puberty _____________________________________________________________________ Mounting and erection ____________________________________________________________________ Coordination of nerves, muscles, & production seminal fluids Substantially precedes ability to produce enough sperm for fertilization ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 41 Metabolic signals Glucose & fatty acids ____________________________________________________________________ ____________________________________________________________________ Leptin from adipocytes Blood concentrations directly related to amount of body fat Leptin receptors: ______________________________________________________ _____________________________________________________________________ _____________________________________________________________________ External factors Environmental factors ___________________________________________________________________ ________________________________________________________________ ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 42 Season of birth (Fig 6-8) particularly in seasonal breeders like sheep Season of birth effects in ram lambs but not bull calves Bitch: _______________________________________________________________ Queen: ______________________________________________________________ Social cues __________________________________________________________________ Phermones: chemical compounds secreted by body, are volatile & detected by olfactory system of same species Swine: ________________________________________________________ (Fig 6-9) ________________________________________________________________ ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 43 Genetics (breed; Table 6-2 ___________________________________________________________________________ Cattle: Angus < Charolais, Brahman ___________________________________________________________________________ Cattle: Holstein < Charolais Swine: White Landrace < Yorkshire Table 6-2. Influence of breed on age at puberty (months) in domestic animals Species Male Female Cattle: Holstein 8 9 Brown Swiss 12 9 Angus 12 10 Hereford 13 11 Brahman 19 17 Dogs: Border collie 9 Bloodhound 12 Whippet 18 Sheep: Rambouillet 9 Finnish Landrace 8 Swine: Meishan 3 3 Large White 6 6 Yorkshire 7 7