Feed formulation techniques for housed ewes
The main purpose of feed formulation for housed ewes is to achieve, through the scientific combination of various feeds, both satisfaction of the ewe's nutritional needs and maximum feed savings, so that feed input costs are reduced to the minimum. Taking a 60 kg adult ewe as an example, the feed formulation techniques for housed ewes under suitable conditions are described below.
?1 Determining feeding standards
Since there is currently no unified feeding standard for ewes in China, the "Nutrient Requirements of Sheep" formulated by the United States (NRC) is used here as the feeding standard. Because ewes have different nutrient requirements during stages such as gestation and lactation, the United States (NRC) divides the year for ewes into 4 different periods: Stage 1 is the non-lactating period or the first 15 weeks of gestation; Stage 2 is the last 6 weeks of gestation or the last 8 weeks of nursing a single lamb; Stage 3 is the first 8 weeks of nursing a single lamb or the last 8 weeks of nursing twin lambs; Stage 4 is the first 8 weeks of nursing twin lambs.
2 Selecting feeds
To achieve a varied combination of feeds, the roughages selected here are Leymus chinensis, alfalfa hay, corn stalks and rice straw, to be combined in a ratio of 2:1:5:2; the concentrates mainly use corn, wheat bran and soybean meal (or soybean cake).
Because the digestible protein requirements differ among stages, the types of concentrate also differ. In Stage 1 and Stage 2, since protein requirements are relatively low, the supplemental concentrate uses corn and wheat bran, mixed in a ratio of 6:4.
In Stage 3 and Stage 4, protein requirements are relatively high, so the supplemental concentrate uses corn, wheat bran and soybean meal (or soybean cake), mixed in a ratio of 6:3:1.
?3 Feed formulas and feed feeding amounts for ewes at each stage
(1) Roughage and concentrate formula for Stage 1.
Roughage formula (daily feeding amount 0.92 kg): Leymus chinensis 20%, alfalfa hay 10%, corn stalks 50%, rice straw 20%; concentrate formula (daily feeding amount 0.545 kg): corn 68.81%, wheat bran 28.44%, calcium hydrogen phosphate 2.2%, salt 0.55%.
(2) Roughage and concentrate formula for Stage 2.
Roughage formula (daily feeding amount 1.52 kg): Leymus chinensis 20%, alfalfa hay 10%, corn stalks 50%, rice straw 20%; concentrate formula (daily feeding amount 0.661 kg): corn 46.29%, wheat bran 50.38%, calcium hydrogen phosphate 2.87%, salt 0.46%.
Ewes fed this formula are short of 6.13 mg of carotene per day, and feeding 0.2 kg of carrots per day can meet the requirement. For supplementation of vitamin A and vitamin D, a vitamin A-D compound preparation can be used, added according to the product instructions.
(3) Roughage and concentrate formula for Stage 3.
Roughage formula (daily feeding amount 1.02 kg): Leymus chinensis 20%, alfalfa hay 10%, corn stalks 50%, rice straw 20%; concentrate formula (daily feeding amount 1.58 kg): corn 65.54%, wheat bran 29.15%, soybean meal 2.41%, calcium hydrogen phosphate 2.41%, salt 0.49%.
(4) Roughage and concentrate formula for Stage 4.
Roughage formula (daily feeding amount 1.19 kg): Leymus chinensis 20%, alfalfa hay 10%, corn stalks 50%, rice straw 20%; concentrate formula (daily feeding amount 1.77 kg): corn 61.16%, wheat bran 29.23%, soybean meal 6.97%, calcium hydrogen phosphate 2.15%, salt 0.49%.