The four production periods of does are dry nonpregnant, pregnant, late gestation and lactating. Does that are open (nonpregnant), or in the early stage of pregnancy (< 95 days), have fairly low nutrient requirements. For open does, the goal is to gain a little weight to be in good condition for breeding. A medium quality pasture, such as in late summer, or a medium quality hay is sufficient to prepare for breeding and the early stage of pregnancy. However, adequate quantities of feed are necessary.
Use the Langston Interactive Nutrient Calculator (LINC) to calculate the nutrient requirements for a 130-pound nonpregnant, mature Boer doe without change in body weight and with intensive pasture grazing. The requirements are 1.50 pounds of total digestible nutrients (TDN), 0.18 pounds of crude protein (CP), 4.03 grams of calcium, and 2.82 grams of phosphorus, with an estimated dry matter intake of 2.31 pounds (based on the composition of fall bermudagrass; 50 percent TDN and 9 percent CP). Feeds used are fall bermudagrass and a mineral supplement. A 130-pound doe is expected to consume the mineral at 0.1 percent of body weight per month = 1.3 pounds/30 days = 0.04 pounds of mineral per day. The estimated 2.27 (2.31-0.04 = 2.27) pounds dry matter intake of fall bermudagrass (3.25 pounds as-fed) provides 1.14 pounds of TDN (76 percent of requirement) and 0.20 lbs of crude protein (111 percent of requirement). In this example, it appears questionable as to whether body weight of the doe could be maintained with this forage, for example, 50 percent TDN). The goats' ability to select higher quality plant parts, as noted above, might enable them to maintain their body weight. In this regard, if they are able to select a diet with a TDN concentration of 60 percent rather than 50 percent then the amount of TDN supplied is (2.27 × 0.60 = 1.36 pounds) which is 91 percent of the required amount, somewhat close to her requirements. Again, it is important to monitor body condition.
Calculate the nutrient requirements for a Boer doeling weighing 70 pounds, gaining 5 pounds per month, and with intensive pasture grazing, using LINC. The requirements are: 1.3 pounds TDN, 0.25 pounds crude protein, 2.98 grams of calcium, and 2.08 grams of phosphorus with a dry matter intake estimate of 2.06 pounds. If we adjust estimated TDN and estimated protein for the forage (questions 7 and 8 in LINC) since the 50 percent TDN of fall bermudagrass is different than the 60 percent assumed, and use 9 percent CP instead of the 12 percent assumed, predicted dry matter intake is 2.32 pounds. Using the same feeds, fall bermudagrass and mineral, with a mineral consumption of 0.02 pounds (1 percent of body weight /month, divided by 30) and using fall bermudagrass for the remainder of her intake (3.3 pounds as fed), both TDN (1.16 pounds intake, 89 percent of requirement) and crude protein (0.21 pounds intake, 84 percent of requirement) are inadequate. To achieve the desired growth rate, supplementation may be necessary. By trying sweet feed as a third feedstuff it is determined, through trial and error, that 0.75 pounds of sweet feed along with 2.0 pounds of fall pasture will provide most of the energy requirement but only 0.19 pounds of crude protein (76 percent of requirement), which is inadequate. By deleting the sweet feed and changing to a 16 percent dairy ration to supply the needed crude protein, it is finally determined that 0.75 lbs of a 16 percent crude protein dairy ration, 2.0 pounds pasture, and 0.02 pounds of mineral will provide 1.3 pounds of TDN (100 percent of requirement) and 0.25 pounds of protein (100 percent of requirement). The weight gain to achieve adequate breeding size should continue to be monitored with possible feeding adjustments made. The lesson here is that this doeling, because of the need for growth, has higher requirements than a mature doe and needs extra nutrition.
Reference: Hart, S. 2008. Meat Goat Nutrition. Pages 58-83 in Proc. 23rd Ann. Goat Field Day, Langston University, Langston, OK.