Table 10–3 Other Mineral Requirements and Maximum Tolerable Concentrations and Vitamin Requirements

Mineral/Vitamin

Unit

Growing and Finishinga

Cows

Maximum Tolerable Level

Gestation

Early Lactation

Magnesium

%

0.10

0.12

0.20

0.40

Potassium

%

0.60

0.60

0.70

3.00

Sodium

%

0.06–0.08

0.06–0.08

0.10

Sulfur

%

0.15

0.15

0.15

0.40

Cobalt

mg/kg

0.10

0.10

0.10

10.00

Copper

mg/kg

10.00

10.00

10.00

100.00

Iodine

mg/kg

0.50

0.50

0.50

50.00

Iron

mg/kg

50.00

50.00

50.00

1000.00

Manganese

mg/kg

20.00

40.00

40.00

1000.00

Selenium

mg/kg

0.10

0.10

0.10

2.00

Zinc

mg/kg

30.00

30.00

30.00

500.00

Vitamin A

IU/kg

2200

2800

3900

Vitamin D

IU/kg

275

275

275

aAlso for breeding bulls.

TABLE 10–4 Adjustment Factors for Dry Matter Intake for Cattlea

Adjustment factor

Multiplier

Breed (BI)

Holstein

1.08

Holstein×Beef

1.04

Empty body fat effect (BFAF)

21.3 (to 350 kg EQW)

1.00

23.8 (400 kg EQW)

0.97

26.5 (450 kg EQW)

0.90

29.0 (500 kg EQW)

0.82

31.5 (550 kg EQW)

0.73

Anabolic implant (ADTV)

1.00

No anabolic stimulant

0.94

Temperature, °C (TEMP1)

>35, no night cooling

0.65

>35, with night cooling

0.90

25 to 35

0.90

15 to 25

1.00

5 to 15

1.03

-5 to 5

1.05

-15 to -5

1.07

<-15

1.16

Mud (MUD1)

None

1.00

Mild (10–20 cm)

0.85

Severe (30–60 cm)

0.70

aNational Research Council, 1987.

For non-pregnant beef cows:

For pregnant cows (last two-thirds of pregnancy):

where

DMI is dry matter intake, kg/d;

SBW is shrunk body weight, kg;

NEma is net energy value of diet for maintenance, Mcal/kg;

Yn is milk production, kg/d;

BI is breed adjustment factor for DMI (Table 10–4);

BFAF is body fat adjustment factor (Table 10–4);

ADTV is feed additive adjustment factor for DMI (Table 10–4);

TEMP1 is temperature adjustment factor for DMI (Table 10–4);

MUD1 is mud adjustment factor for DMI (Table 10–4).

The same environmental adjustments (Table 10–4) are used to adjust intake for all cattle types.

Adjustment of Dry Matter Intake relative to forage allowance for animals grazing:

otherwise:

where

DMI is g predicted dry matter intake per kg SBW using previous equations;

pI is kg predicted dry matter intake adjusted for grazing situations;

FA is daily forage allowance, g/kg SBW/day;

GRAZE is forage availability factor if grazing, %;

IPM is initial pasture mass (kg DM/ha);

GU is grazing unit size (ha);



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