Straw as an alternative roughage source for wintering beef cows

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Source: Manitoba Agriculture, Food and Rural Initiatives

When hay supplies are low, differing options for wintering the cow herd have to be considered. Straw can be used extensively as winter feed if energy, protein, mineral and vitamin requirements are met. Straw does not contain sufficient levels of these nutrients and the use of grain, protein supplements and mineral/vitamin premixes is needed make straw-based wintering diets work well. It is critical to supply all the nutrients the animals need in order for them to maintain good health, body condition, high reproductive rates and desirable weaning weights. It is important to understand the basic nutritional needs of your animals. The nutritional requirements of the beef herd change as the animals move through different physiological stages.

The general nutritional requirements of the breeding herd are listed in Table 1. When comparing the nutrient requirements of the breeding herd to the nutritive value of straw (Table 2) it is clear that straw alone is not sufficient to maintain the animals.

Table 1. Nutritional requirements of the breeding herd1

Class  

Total Digestible Nutrients%

Crude Protein%

Calcium%

Phosphorus%

Mid Gestation

50-53

7

0.20

0.20

Late Gestation 

58

9

0.28

0.23

Lactating

60-65

11-12

0.30

0.26

Replacement Heifers

60-65

8-10

0.30

0.22

Breeding Bulls 

48-50

7-8

0.26

0.20

Yearling Bulls

55-60

7-8

0.23

0.23

1Nutritional requirement varies with body weight, frame size, predicted average daily gain (ADG) and stage of production.

Physical intake of a straw based ration will be restricted due to the fibrous nature of the feed. This can create problems, particularly when beef cows increase intake in response to cold temperatures.  Rumen compaction may occur if straw is fed alone with no readily available energy and/or protein supply for the rumen microbes.

Table 2. Average nutrient values of straw (100% dry matter basis)

 

CP%

TDN%  

Ca%

P%

Wheat Straw

3.9

44

0.18

0.11

Barley Straw

4.9

46

0.13

0.08

Oat Straw

4.5

48

0.26

0.10

Flax Straw

5.4

43

0.26

0.08

Pea Straw

6.4

48

0.60

0.19

 

During cold periods, the energy component of the ration needs to increase approximately 15-20% as the ambient temperature drops to -20 to –25 ºC. In the last trimester of pregnancy, the cow’s nutrient requirements also increase significantly. Therefore, it is important to provide higher quality feed in the form of either good quality alfalfa hay or increase protein and energy supplementation of straw diets.       

When feeding straw several factors need to considered

  1. Feed test: straw sources (i.e. barley versus wheat straw) differ in nutritional content and digestibility. It is critical to know the nutrient content of all feedstuffs in order to provide a balanced ration.
  2. Cattle will digest 1.25% of their body weight of straw in a 24 hour period. 
  3. Diets must be balanced for energy, protein, minerals and vitamins.
  4. Cattle consume greater amounts of one year old straw as it is generally more palatable than freshly baled straw.
  5.  Ammoniation can increase the overall feeding value and intake of straw based diets.
  6. Grinding/chopping straw and feeding as a part of a total mixed rations will increase intakes.
  7. A 2:1 mineral (or 3:1) will be needed. Limestone may also be required if no other forage is fed.
  8. Check the nitrate content.
  9. Pesticide residues in straw from treated fields can harm livestock. Consult individual product labels for specific information.  

Table 3. Differing wintering ration options for gestating beef cows 1400*lbs     

Pre Calving – Cows

 

 

 

#1

#2

#3

#4

#5

#6

#7

#8

Feed Type

Ration – Feed Per Day (lbs based on 1400 lbs cow)

Alfalfa Hay

0

0

0

0

0

0

0

0

Alfalfa Grass Hay

35

0

0

0

16

0

10

0

Grass Hay

0

0

0

0

0

0

0

0

Barley Straw

0

17

19

23

0

23

15

23

Barley Greenfeed

0

0

0

0

19

0

0

0

Corn Silage

0

0

47

0

0

0

32

0

Barley Silage

0

48

0

0

0

0

0

0

Barley Grain

0

0

0

11

0

10

0

0

32% Feedlot Suppl.

0

0.5

0.5

1

0

0

0

0

32% Liquid Suppl.

0

0

0

0

0

2.9

0

0

20% Grain Pellets

0

0

0

0

0

0

0

14

1:1 Mineral

0.12

0

0

0

0

0

0

0

2:1 Mineral

0

0.06

0.06

0.06

0.12

0.2

0.2

0.06

Limestone

0

0

0

0

0

0.2

0

0.2

Blue Salt

0.07

0.07

0.07

0.07

0.07

0.07

0.07

0.07

*Add 5-15% for waste depending on feeding method

 

For a cost comparison on the different ration options vistit the Beef Cow-Calf Cost of Production

In conclusion, the first step is to do an inventory of available feed supplies and feed test. This allows you to match feed available with the animal’s requirements. Please contact the local Manitoba Agriculture Office for feed testing supplies, feed sample submission and ration formulation.

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