Pregnancy in Goats
Gestation length is 145–155 days (average 150 days) and can be affected by breed, litter weight, environment, and parity. Generally, first-kidding does have one or two kids, and in subsequent kiddings, triplets and quadruplets are not uncommon, especially in large, well-fed, heavy milkers. Quintuplets and sextuplets are rare. Progesterone production for maintenance of pregnancy is entirely dependent on the corpus luteum, with a drastic decline in progesterone occurring 12–24 hr before kidding. Induction of parturition is a useful technique to increase survival in dairy goat kids and to catch and separate kids from dams before they suckle in herds with control programs for caprine arthritis encephalitis virus and mycoplasma. Induction with synthetic PGF2α analogues such as cloprostenol (125 mg) or dinoprost tromethamine (10 mg) usually results in delivery of kids ~30–35 hr after injection, whereas dexamethasone (20 mg) requires ~48 hr to induce kidding. Viability of multiple fetuses may be compromised if parturition is induced before day 144.
Pregnancy toxemia in goats is similar to that in sheep (see Pregnancy Toxemia in Ewes and Does). It occurs during the final 6 wk of pregnancy and is more common in overconditioned does and in does pregnant with multiple kids. It is caused by reduced feed intake coupled with high energy demand, leading to ketosis. Treatment depends on severity of the condition and can range from dietary modification with oral administration of propylene glycol to intensive supportive care with administration of IV fluids with dextrose, insulin, and pregnancy induction. Vitamin B12 may also be administered as an appetite stimulant. Lactational ketosis is similar and occurs within the first 3 wk of lactation in high-producing dairy goat breeds; clinical signs include irritability, anorexia, reduced milk production, and weight loss. Treatments include IV glucose, oral glucose, and/or oral propylene glycol, depending on severity. Hypocalcemia or milk fever (see Parturient Paresis in Sheep and Goats) is seen in high-producing, older (>3 yr) dairy goats, but not nearly so frequently, nor as severely, as in cattle. Treatment includes IV administration of calcium gluconate or calcium borogluconate solution.
Vaginal prolapse is fairly common (see Overview of Vaginal and Cervical Prolapse) in does and is believed to have a hereditary component. It may intermittently occur during late pregnancy due to increased intra-abdominal pressure. If complete vaginal prolapse occurs, intervention is required to prevent injury, infection, or dystocia. Owners should be advised that vaginal prolapses will recur with each pregnancy, so they can decide whether to cull the animal.