Management of late pregnancy sheep and goats
Proper management of the doe or ewe in late pregnancy is vital to ensure kid and lamb survival as well as provide for adequate colostrum production and subsequent milk production.
Approximately two-thirds of the birth weight of a developing fetus is gained during the last six weeks of gestation. As a result, the nutritional requirement of the dam for both energy and protein increases during this time. For a 175 pound mature ewe, Total Digestible Nutrients (TDN) requirements increase to 57-66 percent, compared to 55 percent during early gestation. Similarly, crude protein requirement increases to around 11 percent.
The most critical difference is the increase in energy requirement, particularly during the two weeks prior to giving birth. Inadequate nutrition during late gestation may result in pregnancy ketosis, light birth weights, weak lambs and lower milk production. Energy and protein requirements are also increased for animals carrying multiple births. Total energy intake requirements in late gestation increase 16 percent for twin and 31 percent for triplet-carrying ewes compared to ewes carrying singles. Similarly, total crude protein requirements increase 23 percent and 45 percent for twin and triplet carrying ewes, respectively, compared to singles. These increased requirements can be supplied by providing a more nutrient dense diet. Grain supplementation should begin earlier for multiple birth ewes (3-6 weeks pre-lambing) than ewes carrying singles (2 weeks pre-lambing). Many shepherds utilize the rule of thumb that ewes should receive one pound of grain supplement for each lamb they are carrying. Also feed intake can be decreased by the fetuses limiting the amount of space available for the rumen.
Selenium and Vitamin E are critical nutrients during gestation. Soils in Michigan are selenium deficient making supplementation is a must. Selenium is passed from the placenta to the fetus during late gestation, and proper selenium supplementation to does and ewes will assist in preventing white muscle disease in kids and lambs. Selenium is often provided in complete mineral mixes offered free-choice. FDA regulates that selenium concentration in free-choice mineral mixes not exceed 90 PPM, and limits total ration concentration of selenium to 0.3 PPM (intake of 0.7 mg/hd/day). While selenium is a very important trace mineral that is required in small quantities, care should be exercised in formulation as higher intakes can be toxic, according to Michigan State University Extension.
Late gestation does and ewes with inadequate calcium intakes are prone to milk fever. The calcium content of grains is low, whereas forages such as alfalfa hay are generally higher in calcium. Calcium intake should be monitored closely, particularly when feeding corn grain and hay diets. Supplemental calcium may be provided through a complete grain mix.
Does and Ewes should be vaccinated for clostridium perfringes types C & D and tetanus three weeks prior to lambing. Vaccination of does and ewes will provide protection to their offspring at birth.