1. Formulating Rations for Horses Presentation Part 3: Calculating Rations Example 2 #8895-D

2. Example 2 A more difficult ration formulated by using combination of roughage & grain Compare animal’s needs to amount supplied

3. Example 2 If feed does not have enough nutrients, see what other feeds can be added & how much to correct deficiency

4. Example 2 Ration for: – 12-month old yearling – 325 kg (715 lb) – Growing at moderate rate – Expected to mature at 500 kg (1,100 lb) – Timothy hay

5. Example 2 DE (Mcal/kg) Crude Protein % Calcium % Phosphorous % Supplied by Forage 2.0610.80.510.29 Needed by Horse 2.812.60.430.24

6. Example 2 Timothy hay alone does not provide enough energy and crude protein concentration A grain supplement must be added

7. Example 2 Yearlings will eat between 1.8% & 2.7% of body weight (325 kg) Percentages correspond to 5.85 kg & 8.78 kg of total ration – 325 x 0.018 = 5.85 – 325 x 0.027 = 8.78

8. Example 2 Ration should consist of: 2.8 Mcal of DE/kg 60% (0.6) concentrate 40% (0.40) forage

9. Example 2 Determine energy that grain needs to provide ration from the following equation X = energy needed in grain mixture to provide 2.8 Mcals of DE/kg

10. Example 2 2.80 Mcal/kg = (2.06)(0.4) + (X)(0.6) 2.80 Mcal/kg = 0.824 + 0.6X 1.97 Mcal/kg = 0.6X 3.29 Mcal/kg = X

11. Example 2 Corn & oats can be used to meet energy needs of grain mixture Corn contains 3.84 Mcal of DE/kg Oats contain 3.20 Mcals of DE/kg

12. Example 2 To calculate percentage of corn and oats needed, use “Pearson square” method 3.84 3.20 3.29 0.55 0.09 Corn Oats 0.64 parts total

13. Example 2 Insert energy value of: – corn at top left – oats on bottom left – nutritional requirements in middle 3.84 3.20 3.29 0.55 0.09 Corn Oats 0.64 parts total

14. Example 2 Subtract diagonally – 0.55 parts oats (3.84 – 3.29) – 0.09 parts corn (3.29 – 3.20) Always subtract smallest number from largest number 3.84 3.20 3.29 0.55 0.09 Corn Oats 0.64 parts total

15. Example 2 Grain mixture3.29 Mcals of DE/kg Oats 85.90% (0.55 part oats / 0.64 parts total) Corn 14.10% (0.09 parts corn / 0.64 parts total) Nutritionally balanced ration 3.84 3.20 3.29 0.55 0.09 Corn Oats 0.64 parts total

16. Example 2 Because grain mixture is 60% of total ration, multiply each percentage by 60% (0.60) The ration is 51.54% (85.9 x 0.60) oats & 8.46% (14.1 x 0.60) corn 3.84 3.20 3.29 0.55 0.09 Corn Oats 0.64 parts total

17. Example 2 To check the calculations, use the following equation – X = energy needed X = (2.06 Mcals/kg x 0.40) + (3.84 Mcal/kg x 0.0846) + (3.20 Mcal/kg x 0.514) X = 2.8 Mcals/kg

18. Example 2 Calculate crude protein Yearling requires 12.6% protein Timothy hay contains 10.8% CP Corn 10.4% CP Oats 13.3% CP

19. Example 2 X = 10.8% (10.4) + 10.4% (0.0846) + 13.3% (0.5154) X = 4.32% + 0.88% + 6.86% X = 12.06%10.813.81.21.812.6

20. Example 2 Use Pearson square method to calculate level of protein that grain will have to provide to make up protein deficiency