ANSC 340 Lecture Notes - Lecture 17: Artificial Insemination, Estrous Cycle, Ovulation
29 Oct 2016
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Number of estrogen receptors on tonic center decreasing. Number of estrogen rceeptors on surge center increasing. As estrogen receptors decrease in tonic center, estrogen levels in blood rise. Estrogen threshold required for preovulatory surge of gnrh. Season of birth + photoperiod can affect onset of puberty. Ewes born in spring want to cycle in fall. Tend to be smaller because reach puberty earlier. Advantages: will be larger because cycles for first time 1 yr later in fall. Disadvantages: inefficient because paying for more months of feed. How animals are grouped can affect onset of puberty. Cycling females will influence cycling in other females. Small female group + male= accelerated puberty (24 weeks) Does not matter whether contact with male is allowed or if they are separated. Pheromones- chemicals produced by one animal of a species to illicit a physiological or behavioral response in an animal of the same species. Ex: fleming- curling up lip is taking in pheromones.
