Biologic Rhythms PDF

BIOLOGIC RHYTHMS  CHRONOBIOLOGY is a field of science that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar and lunar related rhythms. These cycles are known as biological rhythms.  BIOLOGIC RHYTHMS Diurnal- pertains to activities done...

BIOLOGIC RHYTHMS  CHRONOBIOLOGY is a field of science that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar and lunar related rhythms. These cycles are known as biological rhythms.  BIOLOGIC RHYTHMS Diurnal- pertains to activities done during day time Nocturnal- pertains to activities that happens at night time Crepuscular- “twighlight” Rhythms with different duration Circadian- 24 hrs High frequency- less than 30 min Ultradian – more frequent than 24 hr Infradian- less frequent than 24 hr Circatrigentian- 30 days Annual rhythm INFRADIAN rhythm Cycle duration longer than 24hours Frequency of occurrence in these cycles is lower than that of circadian rhythym CIRCADIAN Rhythms -cycles that occur approximately in 24 hr period - Zeitgebers- “time giver”; factors that sets the rhythm - usually maintained under conditions of constant light or dark  Examples of zeitgebers: –Light- sets rhythms of sleep ; estrus –Barometric pressure –Drugs –feeding CIRCATRIGENTIAN rhythm Cycle of approximately 30 days Sexual cycles of sow and cow come into heat every 21 days Mares come in heat 17-24 days in spring; ewe 16-17 days HIGH FREQUENCY rhythm Heart and respiration rates occur in periods less than 30 minutes ULTRADIAN rhythm Cycles occur more frequent than 24 hours ANNUAL rhythm Reproductive cycles of seasonal breeders Cats corticosteroid, thyroxine and epinephrine release(peaks at winter)  SYSTEMS OF BEHAVIOR Goal oriented behavior of animals Phases of Behavior Appetitive Consummatory Refractory  INGESTIVE  Includes eating behavior Purpose: –Energy attainment –Allelomimetic –Attention seeking Classification of animals based on food preferences Carnivores Herbivores Omnivore  Factors affecting eating behavior Taste Temperature Social facilitation GIT factors Estrogen level SEXUAL  Includes proceptive and receptive behavior by female Courting and mate guarding by male Actual copulation  Factors responsible for SB 1. Genetically determined sex Sex is determined at the moment of conception The chromosomal sex will determine whether the indifferent fetal gonads develop into an ovary or testis 2. Perinatal organizational action of hormones both sexes have genetic potential for male and female behavior Neonatally castrated males will show receptive behavior to other males when treated with Estrogen  Freemartin cow is an example of naturally occurring manipulation of perinatal hormonal action The cow may exhibit masculinized behavior  3. Adult activational action of hormone and anatomical sites Certain level of hormone is necessary for normal sexual behavior, but a higher level of hormones will not increase libido and receptivity  Ovariectomy and castration abolishes estrous behavior in females and sexual behavior in males, respectively However, the more experienced the male, the longer the sexual behavior will persist Prepubertal castration is more effective in eliminating SB  4. Past social and sexual experience ◻ Animal raised in isolation from weaning to adulthood, suppresses sexual behavior ◻ Rams raised in all-male groups from weaning to one year are less sexualy active than those raised with ewes  Homosexual experience only, too much sexual experience or unpleasant experience can lead to sexual abnormalities  5. Attractiveness of potential mate Attractiveness of an estrous bitch’s urine depends on her hormone state Increase estrogen in urine ; more attractive to males  6. External environment Extremely inclement weather will inhibit sexual behavior Human spectators or slippery floors may add to inhibition Males are more affected by environment than females Time of day affects cows  7. CNS FEMALE Hypothalamic control GnRH FSH/ LH Estrogen / Progesterone  Cyclical ovulation –Spontaneous ovulator (bitch, ewe, mare and sow), ovulation occur in LH surge –Induced ovulator (cats) external stimuli for vagina are necessary to trigger LH surge  Olfactory influences and pheromones are very important in swine –The presence of boar near the females pen, stimulates estrous AGONISTIC EPIMELETIC (CARE-GIVING) ET-EPIMELETIC (CARE-SEEKING ELIMINATIVE INVESTIGATORY ALLELOMIMETIC SHELTER SEEKING Any questions?...