Methodology for compiling and analyzing diets for livestock animals

The basis of any balanced diet is the dry matter of the feed. It is in this component that the bulk of the nutrients necessary for the vitality and productivity of livestock animals is concentrated. The technologist's task is to select feed in such a way as to meet the needs of the herd without overloading the digestive system and while maintaining low production costs.

When formulating diets, many factors are taken into account: the type of animal, its age, sex, physiological state, and level of productivity. Individual feeding schemes are developed for each technological direction. In doing so, specialists monitor dozens of feed quality indicators to balance the diet in terms of energy, protein, and minerals.

Basic principles and requirements for ration calculation

• Indicators for cattle — 26–32
• Indicators for pigs — 30
• Indicators for poultry — 32–37 or more
• Dry matter in monogastric compound feed — 87–90%

To compile a high-quality ration, it is necessary to have accurate standards for the animals' needs in energy, proteins, macro- and microelements, as well as vitamins. The enterprise must have up-to-date data on chemical analysis of all feeds used. In the case of a deficiency of individual elements, the diet is balanced using premixes, amino acids, enzymes, pro- and prebiotics, as well as flavoring additives.

Factorial method of calculation: formulas and example of calculations

The needs of the lactating herd are calculated using the factorial method. This approach allows for separate assessment of the organism's expenditure on maintaining vitality and on milk synthesis. The calculation is carried out step-by-step and takes into account the stage of lactation, live weight, and milk quality indicators.

1. Determination of potential dry matter intake (DMI) taking into account the week of lactation.
2. Calculation of the need for metabolizable energy (ME) for life maintenance and lactation.
3. Determination of the need for crude protein (CP) based on endogenous losses and protein yield in milk.
4. Calculation of the need for calcium and phosphorus taking into account their actual digestibility from different types of feed.

Below is an example of calculating the requirement for a lactating cow with a live weight of 500 kg in the 5th week of lactation with a daily milk yield of 20 kg (milk fat content — 3.8%, protein — 3.3%):

• Conversion of 30 kg of 3.8% fat milk to 4% milk (for reference):
  4% M = (3.8 × 30) / 4 = 28.5 kg.
• Need for dry matter (DMI) for milk production and life maintenance:
  DMIprod + maint = (0.372 × 28.5 + 0.0968 × 105.7) = 21 kg/day (where 105.7 is metabolic weight LW^0.75).
• Adjustment for the week of lactation (5th week after calving):
  1 - 2.718^{-0.192 × (5 + 3.67)} = 1 - 0.19 = 0.81.
  Final DMI = 21 × 0.81 ≈ 17 kg/day.
• Calculation of the need for metabolizable energy (ME):
  ME maint = LW^0.75 × 0.540 = 500^0.75 × 0.540 = 57.098 MJ.
  ME milk (per 1 kg of milk) = (0.389 × F%) + (0.229 × P%) + 0.8 = (0.389 × 3.8) + (0.229 × 3.3) + 0.8 = 3.3 MJ.
  ME lact = ME milk × 1.61 × M = 3.3 × 1.61 × 20 = 106.26 MJ.
  Total ME = 57.1 + 106.25 = 163.26 MJ/day.
• Determination of the need for crude protein (CP):
  NCP maint = 0.1 × DM = 0.01 × 17000 = 170 g.
  EPL maint = 2.75 × LW^0.5 = 2.75 × 22.3 = 61.33 g.
  EPL = 0.2 × LW^0.6 = 41.6 × 0.2 = 8.32 g.
  Net Protein maint = 170 + 61.33 + 8.32 = 239.6 g.
  CP maint = Net Protein maint / 0.34 = 239.6 / 34 = 704.8 g.
  Net Protein milk = P milk × M × 0.95 = 33 × 20 × 0.95 = 627 g.
  CP milk = P milk × M / 0.34 = 1941.2 g.
  Total net protein (∑NP) = 239.6 + 627 = 866.6 g.
  Total crude protein (∑CP) = 704.8 + 1941.2 = 2646 g.
• Determination of the need for calcium (Ca):
  Ca maint = 0.031 × LW = 0.031 × 500 = 15.5 g.
  Ca milk = 1.3 × M = 1.3 × 20 = 26 g.
  Total net requirement (∑Ca) = 15.5 + 26 = 41.5 g.
  Taking digestibility into account (coefficient 0.405): Ca = 41.5 / 0.405 = 102.469 g.
• Determination of the need for phosphorus (P):
  Taking digestibility from roughage into account: P = 35 / 0.64 = 54.7 g.

For precise balancing of the diet regarding mineral substances, it is necessary to take into account the digestibility coefficients of elements from different types of feed:

Example for independent calculation: formulate and analyze a ration for a dairy cow with a live weight of 600 kg with a daily milk yield of 30 kg. Milk fat content — 3.8%, protein — 3.3%. The animal's lactation period is 22–120 days after calving.

– soybean and sunflower oilcake – 90 % DM;

1) Determine the standard requirement for the total amount of dry matter and energy. From requirement standards or by the factorial method. For this cow, 19.8 kg of DM and 213.8 MJ of ME are required.

2) Determine the amount of dry matter and energy that needs to be given to the animal per day with roughage and succulent feed – bulky (DMbulk) silage, haylage, hay, beet pulp) and how much with concentrated feed (grain, oilcakes, meals, bran, beet molasses (DMc) ). According to the standard, they should account for:

From the total volume of dry matter – 19.8 kg, it is necessary to subtract the DM of the premix, chalk, and salt (2.6%), i.e.

19.8 × 0.026=0.52 kg

19.8 – 0.52=19.28 kg DM – must be provided by the remaining feed, i.e. (19.8: 2=9.64 kg DM should be contained in bulky feed and 9.64 kg – in concentrates.

3) Calculate the quantity of various types of bulky feed. To do this, it is necessary to know their optimal ratio:

– hay: haylage: silage: pulp = (15–20): (25–30): (45–50): (5–10)

Or calculate the percentage ratio of the feed available on the farm.

EXAMPLE: Based on the dry matter content in 1 t of available feed, the dry matter content in the feed harvested on the farm is determined (by multiplying the quantity of harvested feed by the dry matter content in 1 t of this feed).

The total content and percentage ratio of dry matter in the feed available on the farm are calculated.

Such calculations allow for the use of a uniform feeding regimen for cows throughout the year.

Table 1 – Structure of DM in feed for cow feeding

Alfalfa hay 1800 t*0.85 1530 17.6

4500t*0.50 2250 25.9 alfalfa

Corn silage 12000t*0.35 4200 48.3

Raw pulp 6000 t8 0.12 720 8.2 Total 24300 t 8700 100

4) Based on the cow's daily requirement for dry matter of bulky feed (9.64 kg) and the percentage ratio of dry matter, the quantity of dry matter that must be provided with each bulky feed is determined.

Table 2 – Quantity of dry matter necessary for inclusion

DM kg % DM kg Alfalfa hay 9.64* 17.6/100 = 1.5070 Alfalfa

haylage 9.64* 25.9/100 = 2.50 Corn silage 9.64* 48.3/100 = 4.65 Raw pulp 9.64* 8.2/100 = 0.79 Total = 9.64

5) The quantity of dry matter – the second half of the cow's daily requirement (9.64%) is divided between grain feed and protein supplements. The optimal ratio is – grain feed: protein supplements = 60:40 (%).

Determine the quantity of dry matter in grain feed – 9.64*60/100=5.78 kg and in protein supplements – 9.64*40/100=3.86 kg.

6) Determine the quantity of dry matter that must be provided to the cow with grain feed. The optimal ratio in the concentrate feed mixture, % – corn: wheat: barley: molasses= 46:22:22:10.

7) Determine the quantity of dry matter that the cow should receive with protein supplements. Wheat bran is not a protein supplement, but it is often included in the cow's ration to stimulate digestive processes and supplement nutrients in the ration.

The optimal ratio of protein supplements and bran in the cow's ration – soybean meal: sunflower meal: wheat bran, % =50:35:15

Table 3 – Distribution of dry matter (3.86 kg) between supplements

Supplements DM, kg % DM, kg Soybean meal 3.86* 50/100 = 1.93 Sunflower

3.86* 55/100 =1.35 meal Wheat bran 3.86* 15/100 =0.58 Total 3.86

8) Compose a ration for lactating cows with a live weight of 600 kg, daily milk yield of 30 kg, milk fat content of 3.8%, protein 3.3%, lactation stage 22–120 days after calving.

9) Compose a table with a list of feed included in the ration and the main nutrient indicators necessary for the analysis of the composed ration and its compliance with the cow's requirements.

The feed in the ration includes the figures of previously calculated indicators of kg DM of bulky, concentrated feed, and protein supplements necessary to ensure the cow's daily requirement of 19.8 kg of dry matter.

Determine the content of each feed in % by DM.

1.7 kg DM of hay – x %

10) Calculate how much DM of each feed included in the ration accounts for per 1 kg DM of the cow's daily requirement.

Per 100 kg DM – 8.6 kg DM of feed

1 kg DM – X kg DM of feed

X= = 0.086 kg DM of alfalfa hay per 1 kg DM of the ration

11) Based on the composition of feed included in the ration and the quantity of DM of the feed (in 1 kg DM of the ration), the feed requirement is determined.

Example: alfalfa hay. 1 kg DM of hay contains 8.2 MJ of ME (metabolizable energy). 1 kg DM of the ration contains 0.086 kg DM of hay: 0.086 (kg) × 8.2 MJ = 0.71 MJ.

12). When calculating the content of RUP (rumen-undegradable protein) and RDP (rumen-degradable protein) in the ration, the quantity of protein formed by rumen microorganisms of ruminants and the use of fractions A, B, and C during the breakdown of CP (crude protein) are taken into account.

In the example of composing a ration for a cow weighing 600 kg, with a milk yield of 30 kg, milk fat content of 3.8% and protein 3.3% during the lactation period of 22–120 days after calving, the % increase in RUP and RDP when using different types of feed is taken into account.

Table 4 – RUP and RDP content in ration feed

Feed RUP RDP Alfalfa hay 139 202.3 Alfalfa haylage 154.5 204.97 Corn silage 141.3 225.7 Raw pulp 151.5 250 Grain: corn 122.1 220.9 wheat 106.0 204.1 barley 115.5 201.8 Soybean meal 109.3 205 Sunflower meal 116.8 203.2 Wheat bran 130.4 200 Beet molasses 111.1 208.3

Table 5 – Composition of the daily ration for lactating cows with a live weight of 600 kg, daily milk yield of 30 kg, milk contains 3.8% fat, 3.3% protein, lactation period 22–120 days after calving

ME, RUP, ADF, NSC

Feed kg/1 DM, g RDP, g NDF Ca, g S, g Na, g kg % MJ g g g tot avail tot avail g g

1.7 8.6 0.086 0.71 13.33 2.63 10.6 34.1 26.8 19.2 1.3 0.39 0.22 0.132 0.26 2.18 0.24 0.009 0.64

2.5 12.6 0.126 1.18 20.79 5.06 15.76 57.96 35.28 30.11 2.14 0.84 0.26 0.16 0.33 3.15 0.30 0.08 0.78

4.65 23.5 0.235 2.26 21.15 6.31 14.85 117.5 70.5 76.14 0.68 0.20 0.56 0.36 0.45 3.06 0.33 0.02 0.71

Wet beet pulp 0.79 4 0.04 0.42 3 3.03 4.0 15.6 11.2 17.6 0.36 0.11 0.04 0.03 0.09 0.38 0.12 0.12 0.07 corn 2.66 13.4 0.134 1.76 12.7 6.59 16.35 12.7 4.6 100.9 0.05 0.03 0.4 0.28 0.16 0.56 0.13 0.13 0.11 wheat 1.27 6.4 0.064 0.83 8.3 2.01 13.06 8.6 2.8 44.4 0.03 0.02 0.28 0.20 0.10 0.32 0.10 0.01 0.07 barley 1.27 6.4 0.064 0.78 7.9 1.96 12.51 13.3 4.6 39.5 0.04 0.02 0.25 0.18 0.09 0.36 0.08 0.01 0.08

0.58 3.0 0.03 0.37 2.3 0.44 2.0 – – 24.5 0.05 0.03 0.01 0.01 0.09 1.82 0.18 0.44 –

Soybean meal 1.93 9.8 0.098 1.48 45.1 27.5 16.61 19.6 10.2 20.0 0.27 0.16 0.56 0.41 0.22 1.69 0.35 0.04 0.04

1.35 6.8 0.068 0.83 24.82 4.45 20.32 30.6 19.38 2.7 0.29 0.18 0.68 0.48 0.38 0.65 0.18 0.01 0.06

0.58 2.9+ 0.029 0.31 5 0.91 4.0 12.3 4.5 8.6 0.05 0.03 0.23 0.16 0.08 0.28 0.07 0.01 0.01

Premix 0.2 1.0 0.01 0.08 1.4 0.2 1.1 3.4 1.2 2.4 0.04 0.02 0.08 0.06 0.05 0.12 0.03 0.01 0.01

Chalk 0.2 1.0 0.01 3.8 2.85

0.12 0.6 0.006 2.37 3.6

Total 19.8 100.0 1.0 11.01 165.79 61.55 131.17 325.66 191.1 386.3 9.1 4.68 3.57 2.65 2.3 14.57 2.09 3.259 6.18

10.7 168 56 112 6.5 2.7 3.4 2.3 1.8 10.2 2 2.3 3.6 g/kg DM 330 210 440

Ca availability coefficient in forage is 30 %, in concentrates – 60 %.

P availability coefficient in forage is 64 %, in concentrates – 70 %, NSC – non-structural carbohydrates.

EXAMPLE: alfalfa hay in 0.086 kg of DM was 1.87 g, RDP – 5.19; taking into account and using N-fractions of SB and the amount was 2.63 g (0.086 × 22 g × 139)/100) RUP and 10.62 g (0.086 × 61 × 2012.3/100) respectively.

An analysis is performed based on the formulated ration.

13) The final version of the ration should be in table format.

Determine the amount of natural feed to be included in the ration.

EXAMPLE: Alfalfa hay: 1 kg contains 85 % dry matter or 850 g or 0.85 kg of feed dry matter. Total DM from hay included in the ration is 1.7 kg; 1.7:0.85 = 2 kg of alfalfa hay.

When analyzing the ration, minor discrepancies with the standards are observed (but they are acceptable).

The ration must be supplemented with vitamins and minerals. Premix for dairy cows includes per 1 kg of DM: vit. A – 8000 IU, D3 – 1500, E – 30 mg, Co – 0.3 mg, J2 – 1.2 mg, Fe – 10 mg, Mn – 35 mg, Se – 0.5 mg, Zn – 60 mg.

Moisture content in the natural feed of the ration is 52.5 %.

41.68 kg of natural feed – 100 %

19.8 kg of dry matter – x %

X = = 47.5 % DM. Moisture = 100–47.5 = 52.5 %

41.68 Table 6 – Ration for lactating cows with a live weight of 600 kg, daily milk yield 30 kg, milk fat 3.8 %, protein – 3.3 %, lactation period

22–120 days after calving (NF – natural feed)

Feed NF, kg NF, % DM, kg DM, %

1 2 3 4 5 Hay

2 4.8 1.70 8.6 alfalfa Haylage

5.56 13.3 2.50 12.6 alfalfa Silage

15.50 37.2 4.65 23.5 corn Wet beet pulp 6.58 15.8 0.79 4.0 Grits:

3.02 7.2 2.66 13.4 corn Wheat 1.44 3.5 1.27 6.4 Barley 1.44 3.5 1.27 6.4 Molasses 1.33 3.2 0.58 3.0

1 2 3 4 5 Soybean meal 2.14 5.1 1.93 9.8 Meal

1.50 3.6 1.35 6.8 sunflower Bran

0.65 1.6 0.58 2.9 wheat Premix 0.2 0.5 0.2 1.0 Chalk 0.2 0.5 0.2 1.0 Table

0.12 0.2 0.2 0.6 salt Total 41.68 100.0 19.8 100.0

Per 1 head/day Standard Per 1 kg DM Standard DM, kg 19.8 19.8 – – ME, MJ 165.79 212 – 10.7 CP, g 3282.6 3326 165.79 168 RDP, g 1218.7 1109 61.55 56 RUP, g 2597.2 2218 131.17 112 NDF, g 4950–6534 325.66 250–330 ADF, g 3783.8 3366–4158 191.1 170–210 NSC, g 7648.7 7128–8712 386.3 360–440 Ca total, g 180.2 128.7 9.1 6.5 Ca avail, g 92.7 53.5 4.68 2.7 P total, g 70.7 67.3 3.57 3.4 P avail, g 5.25 45.5 2.65 2.3 Mg, g 45.54 35.6 2.3 1.8 K, g 288.5 202 14.57 10.2 S, g 41.38 39.6 2.09 2 Na, g 64.5 45.5 3.258 2.3 CL, g 122.4 71.3 6.18 3.6

Table 7 – Feed composition for cattle, sheep, horses, rabbits per 1 kg of dry matter

ME, CP, RDP, RUP, TP, CF, NDF, ADF, CFat, CA, NSC, NFE, Starch, Sugar,

MJ g g g g g g g g g g g g g

15 85 8.2 155 22 61 83 300 396 312 21 100 323 424 24

55 45 9.4 165 26 61 87 228 460 280 36 100 239 471 16

70 30 9.6 90 19 28 47 233 500 300 40 46 324 591 120 90

Wet beet pulp 88 12 10.4 74 33 16 49 200 390 280 10 70 456 646 10 corn 12 88 13.1 95 33 25 58 24 95 34 42 15 753 832 680 35 wheat 12 88 13 130 28 49 78 21 134 44 23 20 693 816 670 30 barley 12 88 12.2 124 23 48 71 53 208 72 22 29 617 772 570 29

Soybean meal 10 90 15.1 460 261 83 344 55 200 104 81 55 204 349 17 110

110 90 12.2 365 56 147 203 148 450 285 82 64 39 361 28 90

11 89 10.6 173 23 70 93 114 425 155 43 63 296 607 190 70

23 77 12.2 78 12 32 44 4 818 817 716

Table 8 – Mineral composition of feed for cattle g/kg DM mg/kg DM

15.2 2.6 3 25.3 0.1 7.4 2.5 0.45 9 – 286 35 0.2 24 2.9

17 2.1 2.6 25 0.6 6.2 2.4 0.65 7.7 735 65 0.2 25 2.4