Lab Two: Sheep and Goat Repro

• Ewes have a gestation length of 147 days.
• Does have a gestation length of 150 days.
• Both ewe and does have cotyledonary placenta and have one to three offspring
• Birth is the termination of pregnancy.
• Afterbirth is the extraembryonic membranes that had formed around the embryo in the early pregnancy are shed at birth.
• Placenta is the membranes that attach to the uterus during pregnancy.
• Parturition is initiated by the release of cortisol from the fetal adrenal cortex. This leads to a decline in progesterone and an increase in estrogen, prostaglandin, and oxytocin increase, causing uterine contractions.
• During parturition, the cervix relaxes.
• Pressure generated by the uterine muscles on the contents of the uterus permits passage of the fetus into the vagina to the exterior.
• Relaxin is thought to aid in parturition.
• Relaxin originates in the corpus luteum or placenta and helps to relax the pelvic cartilage and ligaments.
• Offspring typically assume diving position, the position of least resistance for passage through the pelvic area and birth canal.
• Calves, foals, lambs, and kids typically assume diving position.
• Piglets do not orient themselves in any specific position.
• Kids and lambs can be born without dystocia in backwards position.
• Diagram

  A) Diving

  B) Breech

  C) Upside down and backwards

  D) Head back

  E) Backwards

  
• Goats experience dystocia less than five percent of the time.
• Goats experience dystocia because of malpresentation
• Sheep experience dystocia at rates of four to 35 percent of the time. The highest rates are associated with yearling ewes and are highly variable by breed.
• Ewes experience dystocia because of excessive birth weight, malpresentation, and complication due to multiple offspring.
• Reproductive loss can be minimized by good management decisions for breeding animals, keep animals healthy, provide adequate nutrition, select genetically superior animals, and pay extra attention before, during, and after parturition.
• Goats have an estrus cycle every 18 to 21 days.
• Goats experience estrus for 1 to 3 days of their estrus cycle.
• The first breeding for goats can occur at 6 to 9 months of age, at 70 to 85 pounds, but producers often wait longer to avoid stunting growth.
• Angora goats are often first bred at 18 to 24 months of age.
• The breeding season for goats in September to November.
• The kidding season for goats if February to April.
• Lactation for goats lasts 7 to 10 months.
• Twin kidding is common in goats.
• Triplet delivery is not unusual for goats.
• Mature goats typically have at least 2 kids.
• Young does have about 1.5 kids.
• The body weight of newborn kids is typically 5 to 8 pounds, with singles being heavier than multiples, and buck kids weighing more than doe kids.
• The male to female ratio in goats 115 to 100.
• Do not assist in parturition unless necessary.
• Start to assist in parturition after excessive straining for 30 minutes.
• Breech is not uncommon in goats, but there needs to be rapid delivery to prevent suffocation.
• Small, well lubricated hands are needed to assist does in delivery.
• When assisting parturition, pull only during contractions and be gentle to avoid internal damage