University:
Sam Houston State University
Course:
BIOL 2413 | General Zoology
Academic year:

2021
Views:

417

Pages:

13
Author:

larbiwxcvbn

Parturition and Related Problems and Illnesses Average length of gestation Species Length in Days Avg. in Months* Cattle 279-292 9 Goats 145-155 5 Sheep 144-151 5 Swine 112-115 3 mo. 3 wks. 3 days Horse 330-342 11 *Average varies with animals and breeds. Average length of gestation Species Length in Days Avg. in Months* Dog 58-70 2 Cat 58-65 2 Rabbit 30-35 1 600-660 20-22 Elephant *Average varies with animals and breeds. schistosomus reflexus Parturition Giving birth: called calving in cattle lambing in sheep farrowing in swine kidding in goats whelping in dogs Parturition Parturition Parturition Hormonal Changes As the fetus approaches full term:    Progesterone levels decline. Estrogen levels increase, preparing uterus for delivery. Fetus releases hormone (cortisone) stimulating the beginning of the birth process. Parturition or delivery of the newborn occurs normally at a point when the fetus is capable of surviving on its own. 3 stages of parturition Preparatory Fetal Expulsion Expulsion of placenta or afterbirth Preparatory Stage (2-6 hours) Calf rotates to upright position Uterine contractions begin Water sac expelled Delivery (1 hour or less) Cow usually lying down Fetus enters birth canal Front feet and head protrude first Calf delivery completed Cleaning (2-8 hours) Caruncle-cotyledon (button) attachments relax Uterine contractions expel membranes