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var _gaq = _gaq || []; (function() { You're Kidding! Basics of Small Ruminant Reproduction Part One
Female goats and sheep (does and ewes, respectively) reach sexual maturity between 6-9 months of age, or at 60-65% of their adult weight. Please note: does can have their first estrus as early as 3 months of age, so keep them separate from bucks! If ewes and does get bred at too low a body weight, their growth may be stunted, resulting in increased risk of dystocia (difficulty giving birth). As I mentioned above, small ruminants undergo estrus only during the shortest days of the year (August-March). Throughout the breeding season, the females continue to cycle through heats unless bred. Behavioral estrus is when the female is receptive to the male and allows herself to be mounted. This stage lasts 12-36 hours. Diestrus is the stage when the uterus prepares for pregnancy. This lasts 14-20 days. If the females are not pregnant, the cycle starts over again with behavioral estrus. If they are pregnant, the female is no longer receptive to the male and you can expect delivery of a kid or lamb 145-150 days from the breeding. During the longest days of the year, most females stop ovulating altogether and this is referred to as anestrus.
During pregnancy, 85% of fetal growth occurs during the last trimester, so female nutrition does not need to be increased until days 100-150. In fact, overweight does and ewes are prone to pregnancy toxemia, a metabolic disorder that occurs during the last few weeks of pregnancy as the energy demands of the kids or lambs increase and the mother starts metabolizing fat. Keeping your pregnant ewes and does in a fit body condition and increasing nutrient consumption only during the last trimester should prevent pregnancy toxemia. Signs of this disease include lethargy, inappetance, weakness and poor muscle control/balance. Unfortunately, treatment of pregnancy toxemia is usually unsuccessful, so prevention is the key. Exercise is encouraged during pregnancy because it not only helps maintain a good body condition but it reduces the risk of dystocia.
As parturition (birthing) approaches, it is helpful to move the doe or ewe to a clean, dry place where she can be monitored. It is also recommended that ewes and does be vaccinated against clostridium perfringens type C & D and clostridium tetani (CDT vaccine) late in pregnancy so that antibodies for these diseases will be passed onto the kids and lambs via the milk after they are born. Next month, check in again for part two of "Basics of Small Ruminant Reproduction" where I will cover parturition (including dystocia), colostrum and processing of young lambs and kids! Glossary: Ruminant - one of the order of animals, including cattle, sheep, goats, deer, and antelopes, which have a stomach with four complete cavities (rumen, reticulum, omasum, abomasum), through which the food passes in digestion. Small ruminant includes sheep and goats Goat terms Doe - adult female Buck - adult male Wether - castrated male Kid - young goat Kidding - birthing Sheep terms Ewe - adult female Ram - adult male Wether - castrated male Lamb - young sheep Lambing - birthing Parturition - birthing process Dystocia - difficult or abnormal birth Estrus - the state of sexual excitability when the female of most mammals is receptive to the male and capable of conceiving, aka "heat" Diestrus - a period of sexual quiescence that intervenes between two periods of estrus Anestrus - An interval of sexual inactivity between two periods of estrus in female mammals that breed cyclically
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