Telephone: 01768 899513 | Mobile: 07711 034141 | Email: jerry@lakelandscottish.co.uk
15th October 2020

Ruminant Nutrition for Beef


Introduction

The nutrition needs for beef animals follows the same principals outlined in the Lakeland Scottish Feeds & Services website entitled “Ruminant Nutrition”.
We recommend that the student should read this first, however those who already have a basic knowledge of ruminant nutrition should find this section of interest and perhaps even useful!

Beef production is obviously split into different priorities. For the dairy cow, the focus is on milk production and pregnancy, this is also true for the suckler cow but on a much lower milk production scale.
The main area of focus for beef is that of growth. The replacement heifers for the suckler herd and the growth of cattle to supply the market for beef.
The growth of the beef for the meat market is made up of many different management systems.
This guide looks at the best ways of managing animals within the variation of techniques that we use in this industry.

UK beef production has its roots firmly embedded in tradition.
The evolution of modern beef farming is based on two systems.
Pure beef breeds and their interbreeding, and pure and crossbred dairy beef.

The following text is not designed to be commercial.

Please visit our website at lakescot.co.uk for information about our beef system feed supplements.

The Beef Breeds

There is also a distinction between Suckler beef, (where the calves are left with their dams (mothers) until they are weaned: and Managed beef (where calves are separated from their dams soon after birth and reared using bought in feeds).

The pure beef breeds broadly fall into three categories:

  • Upland native breeds, E.g. Highland cattle, Aberdeen Angus, Galloway, Welsh Black, Luing, etc
  • Pastoral native breeds, E.g. Beef Shorthorn, Hereford, North Devon, Sussex, etc
  • Continental, E.g. Limousin, Charolais, Belgian Blue, Simmental, etc.

These breeds evolved to suit the local grazing and management conditions.
Generally, the pedigree (pure-bred) stock are retained for breeding stock bulls for cross breeding. The best bulls are retained to further improve the pure-bred blood lines and the rest go for meat.

Commercial suckler cows are generally dairy crosses or pure-bred upland and pastoral breeds which have been served with any of the main beef bred bulls with the objective of producing a dam which is then crossed with another beef breed to produce a commercial carcass for the food chain.

The Dairy Beef Systems

UK dairy breeds include the following breeds:

  • Holstein, Friesian, Holstein/Friesian, Ayrshire, South Devon, Jersey, Guernsey, and many other imported breeds like Brown Swiss, Montbeliarde, Norwegian Red, Swedish Red, MRI etc.

These breeds are primarily used for producing milk. The most popular breed being the Holstein/Friesian. Unfortunately, the dairy breeds do not generally have the best conformation for meat production (Montbeliarde being an exception,) so the dairy farmers use mainly continental beef bulls to serve cows that they do not wish to breed dairy heifers from.

They also have a choice as to whether or not to try and rear pure-bred bull calves for beef.
This has become less of an issue when the farmer can use sexed semen for dairy heifer calves.

Pure bred Holstein beef is considered to be unprofitable to rear and attracts a very poor market price in the event that bulls, or steers are reared through to marketing.

The matriarch of the glen

Aims & Objectives for Beef Feeding Plans

Rationing the Suckler cow and its beef calf should reflect the need to achieve a target level of productivity. I believe that there are four steps in planning the appropriate feeding regime:

  1. Agree a target level of performance requirements.
    • For Growing & Finishing Cattle.
      • Target slaughter, or disposal weight. (Tables 3 a to 3 e)
      • Length of feeding period.
      • Required daily live weight gain.
      • Preferred housing & feeding system to be used.
      • Timing of subsidy payments.
    • For the Cow.
      • Milk yield and stage of pregnancy and Preferred housing & feeding system to be used depending on time of year of calving.
  2. Formulate the ration.
    • Feed intake levels.
    • Energy & protein needs.
    • Nutrient content of the feedstuffs to be used.
    • Balancing the ration.
  3. Working out the quantity and cost of the feeds required.
  4. Flexibility of rationing.
    • Will you be able to adjust the diets to match the actual quality of the forage you finish up with? Or can you take advantage of better value for money substitutes?

Diet planning is not usually aimed at grazing cattle, although it should be borne in mind that grazing management is bound to have a big effect on performance, especially when sward quality is deteriorating in the summer droughts, or autumn decline.

Housed cattle are usually the ones to be rationed according to the agreed target level of performance.

Table 1 shows the normal variation of beef cattle groupings commonly found on suckler units.
The variability of the groups can make achieving an ideal diet for all of the animals in a group quite difficult.
There is frequently a need to compromise the ideal balance of the diet and employ a tactic of feeding a forage balancing supplementary feed which gets close enough to the requirements of the average animal in the group and achieving an acceptable compromise in performance.

A typical example of this is to be seen where the earlier finishing heifers are fed the same ration as the later finishing bulls. Care has to be taken that the heifers do not get over fat on the ration.

Table 1: Suckler Systems

Spring Calvers
Heifer Calves Some Bull Calves
1. Spring Calving Hill Cows
Suckled & Grazed Suckled & Creep fed
Calves weaned November
Minerals
Wintered on Grower Diet
Out wintered
Silage & Minerals
Housed
Semi Intensive Silage Grower Diet
Spring Grass
Castrate Bulls 12 Months
Grass & Minerals Either Finish Bulls in house 16 months
Or Turn out & Store(Grow)(Steers)
Re-House Sell lightweight off
grass as store cattle
Sell medium off grass
Or Finish at 24 months Or Re-house & finish at 24 months
Spring Grass Or Replacements calving
24, 30, or 36 months
Or Grass finish at 24 to 30 months
(Prime Beef)
Autumn Calvers
2. Autumn Calving Hill Cows
Suckled & Trough fed Suckled & Creep fed
Turn out
Grass fed & sold October Grass fed & sold October
as light stores as medium stores
Re-house
Reared as replacements Steers finished 21 months (April)
Turn Out
Sold Heavy Stores Some Steers Grass finished to 24 months
Or Reared as replacements

Target Setting

Setting targets is important if cash flow and profit & loss forecasts are to be met.
Checking the current performance standards is a pretty good base to start from. Check on current slaughter weights, carcass weights and EC fat class classification levels, and decide what needs to be improved on and what factors have been responsible for impeding performance.

Setting performance targets

This is a relatively simple but important task, vital if the enterprise is to be properly budgeted. (see Table X)

Table X

Start weight
Final weight
Average weight
Total weight gain
Number of days required to finish
Target daily liveweight gain

The next step in planning has to be assessment of the feed requirements for the job. In order to do this, we need to know the following information as shown in table Y.

Table Y

Feed Analysis Daily Ration Feed Budget
Feed available DM(%) ME (MJ/Kg DM) CP (%) DM (Kg) ME (MJ) CP (grams) Fresh Weight (Kg) Feed Quantities
Per head (Kg) Total (Tonnes)
Concentrates
Forages

Some consideration should be given to the system best suited for the type of farm, buildings, forage quality and availability and the returns needed.
Planning this is a much more subjective process. Personal preferences are important here but have to be kept realistic.
I suggest that a good place to start is by looking closely at the type of animal that is best suited to your inputs.

Early maturing UK Beef breeds are well suited to the low input forage-based systems but have a tendency to get fat easily. Big Continental breeds tend to need a more concentrated ration if they are to be finished at the best marketing weights. The UK Breed / Continental cross is probably the most popular type of beef animal because it falls nicely between the extremes.
Looking at birth weights of typical breeds of cattle will give a good indication of the variation expected in the natural mature weights.
Table 2 shows the average birth weights of common breeds of cattle. These weights are directly related to the mature animal weights of the same breeds. Genetic progress has generally resulted in small increases in birthweights over the years, but these averages are not far off the mark!
When selecting crosses the ease of fattening needs to be closely considered, for example Ayrshire cross beef will fatten earlier and much more easily than Holstein cross beef.

Table 2

Calf Birth Weights of Common Breeds of Cattle

AFRC 1992 and other sources breed averages show a wide variance on mature cow weights.

Breed of Sire Bull Calf Heifer Calf Average Mature Dam Weight
Angus 28 26 27.1 Angus 550
Ayrshire 35 32.6 33.8 Ayrshire 525
Charolais 44 40.9 42.5 Charolais 800
Friesian 39 36.3 37.6 Friesian 617
Guernsey 33 30.7 31.9 Guernsey 475
Galloway 29 27.4 28.2 Galloway 520
Hereford 26 33.5 34.8 Hereford 540
Holstein 45 41.9 43 Holstein 720
Jersey 26 24.2 25.1 Jersey 450
Limousin 39 36.3 37.7 Limousin 650
Belgian Blue 51.6 47.6 49.2 Belgian Blue 780
Simmental 44 40.9 42.5 Simmental 680

Twins = Single Calf Weight x 1.75

Energy requirements are based on the bull calf weight given above divided by 40 x the calculated requirement for the 40 kg calf.

Table 3a

Slaughter weights of cereal beef (bulls)

10 – 14 months (Slaughtered at fat class 3)

Breed/Cross Slaughter Weight
Friesian x Holstein* (F) 460
Aberdeen Angus/Hereford x Friesian (AA x F, He x F) Not recommended
Belgian Blue x Friesian (BB x F) 500
Simmental x Charolais (S x F, Ch x F) 520
Limousin x Friesian** (L x F) 490

* Only Recommended system for this cross
** Most popular dairy cross for beef

Table 3 a (above) shows slaughter weights based on required carcass weights and conformation to supply the meat chain with their required meat cut sizes. There is also some requirement for larger animals and these tend to be required by individual butchers rather than the mass market chain.

*EC Carcass classification scheme.

In the E C scheme, the carcases are classified on a scale 1(Leanest), 2, 3, 4L, 4H, 5L, 5H (Fattest). Preferred fat classes 3 and 4L have a back-fat thickness of about 3 mm and 4.5 mm respectively.

Body Condition Scoring

Body condition score represents a pretty good indication of nutritional status. The assessment of condition should therefore be used to plan feeding management.
Body condition score is based on a system of inspection and handling on a scale 1 (Thin) to 5 (Fat).
The technique is to grip the loin with the thumb curled under the edge of the transverse processes of the spine and use the ball of the thumb to feel the fat thickness over the bone.

Score 1 Bony with no detectable fat cover
Score 2 The bones of the transverse processes can be felt but they are rounded by a thin fat cover.
Score 3 The transverse processes can only be felt with firm pressure.
Score 4 The bone cannot be felt even with firm pressure.
Score 5 The cow is obviously very fat with puffy deposits around the tail head.

The suckler cow should vary in score between 2 and 3 according to her cycle and stage of pregnancy. In practice, many suckler cows tend to be 3 to 4L to H.

Season Target Score Spring Calver Autumn Calver
Spring 3 Calving Pregnant / Suckling
Summer 2.5 Bulling / Suckling Weaning
Autumn 3 Weaning Calving
Winter 3 Pregnant / Dry Bulling / Suckling

Cattle feeding on grass

Cattle feeding on grass

The Tables below from 3b to 3e show the typical slaughter weights achieved according to the rate of daily live weight gain for four different finishing systems.
At first glance the tables don’t look logical with faster growing animals being killed at lower carcass weights. The reason for this is that they achieve the right conformation and fat class earlier than slower growing animals which achieve their correct fat class at higher carcass weights. (see notes below)

Housed cattle on silage & concentrates, mainly bulls but also steers & heifers.

Table 3b

Slaughter weights of beef from grass & maize silage

12 – 18 Months

Daily gain from three months (Kg)
0.8 0.9 1 1.1 1.2 1.3
Breed Sex Fat Class
F* Bull 3 520 515 505 490 475
Steer 3/4L 510 500 485 460
Heifer 4L 460 475
He x F Bull 3 500 490 475 460
Steer 4L 475 460 440
Heifer 4L 410 370
BB x F Bull 3 560 550 540 525 510
Steer 3/4L 540 530 520 505 490
Heifer 4L 480 465 445
CH x F
S x F
Bull 3 575 565 555 540 525
Steer 3/4L 560 550 535 520 490
Heifer 4L 500 485 460
L x F Bull 3 545 540 530 520 505
Steer 3/4L 535 525 515 505 490
Heifer 4L 480 460 440

* Note this system is not particularly good for Holstein beef, the poor confirmation and high maturity weight of the dairy character of the Holstein means that they will tend to grow lean rather than fat, and hence take longer to finish. Animals which exhibit the blockier Friesian type conformation tend to be better suited to the system.

It is the case in all the crosses that exhibit the more traditional the Friesian conformation : the better the resulting conformation and killing out weight at finish.

Table 3c

Classic 18 Month Beef

15 to 20 months

Autumn born dairy bred calves, reared in the first winter, grazed and finished in the second winter on silage and concentrates. Steers and heifers.

Daily gain in finishing winter period (Kg)
0.7 0.8 0.9 1 1.1 1.2
Breed Sex Fat Class
F Steer 4L 520 510 490 470
Heifer 4L 480 465 450
He x F Steer 4L 500 480 460 440
Heifer 3/4L 435 415 375
BB x F Steer 3/4L 550 535 525 510
Heifer 4L 490 485 470 450
CH x F
S x F
Steer 3/4L 570 560 545 525 500
Heifer 4L 500 495 485 455
L x F* Steer 3/4L 545 535 530 520 500
Heifer 4L 485 480 465 445

L x F* This system is extremely popular with the main autumn calving dairy herds in the west.
there is a good level of reliability in the system and the animals tend to come through with a surprising evenness of character.

Cattle feeding from trough

Table 3d

Winter finishing of suckled calves and stores

15 to 26 months

Suckled calves up to 1 year and stores 15 to 20 months fed rationed concentrates and silage to appetite.
Older stores are also fed on the same system to finish at 20 to 26 months, usually after the second subsidy has been drawn.

Daily gain in finishing (Kg) to fat class 4L
0.7 0.8 0.9 1.0 1.1 1.2
Slaughter weight
UK breeds & crosses (light weight, e.g. Hereford, Angus, Galloway, Welsh Black etc.)
Suckled Calf Steer 486 475 455 425
Heifer 415 405 375
Older Store Steer 510 500 475 445
Heifer 435 425 400
Continental breeds & crosses ( heavy weight, e.g. Charolais, Simmental, Limousin, etc.)
Suckled Calf Steer 540 535 525 515 490
Heifer 475 465 450 425
Older Store Steer 575 570 560 550 530
Heifer 500 490 475 450

There are many variations on this basic system; some farmers use home grown roots and turnips to supplement the silage, some use Draft or Brewers Grains, and some prefer to base the finishing ration on other bought in feeds from the human food processing industries.

Table 3e

Suckler Bull Beef

10 to 12 Months or 14 to 18 months

Daily Gain 1.0 1.1 1.2 1.3 1.4 1.5
Slaughter Weight (Kg)
UK Breed/Cross EC fat class 3 to 4 L. 475 470 460 440
Continentals & Crosses EC Fat class 3 530 525 520 515 500 485

Fattening Notes:

  1. The speed at which cattle fatten is directly related to the rate of daily liveweight gain. As the rate of daily gain increases so does the rate of fat cover.
    I am sure that this can be manipulated by dietary adjustment.
  2. Cattle do not normally finish quickly; this means that there can be quite a range in possible slaughter weights within a particular EC fat class for the same type of cross. This will be directly related to the type and quality of diet that the animal is reared on.
  3. The difference in rate of fattening has major effects on the normal slaughter weights at fat classes 3 and 4 L. Most buyers are looking for cattle that will classify as 3 and 4 L.
  4. Continental crosses tend to mature later and heavier so in order to provide a 3 to 4 L carcass at the required weight, the animal has to be finished light for its breed. This means that the continental type cross is more suited to the intensive systems with high target daily liveweight gains, like the cereal beef system.
  5. Conversely early maturing, light weight British breed crosses are much better suited to high forage systems with lower liveweight gains in order to avoid the carcass from becoming over fat to quickly.
  6. Individual animals can show considerable variance in performance from the group. Regular assessment of the individual is important in order to select the optimum feeding regime for the animals concerned. Regular weighing and handling in order to determine the right moment to market the animal at its optimum weight and class, is essential if the best prices are to be obtained.
  7. Slow growers are usually pretty inefficient at converting food into liveweight gain and are best slaughtered at the bottom of the fat class in order to prevent them from losing too much money as they slowly increase in weight.
  8. Fast growers should be allowed to get to the higher weights within the target fat class, because if they are converting feed into liveweight efficiently, they will be contributing profit.
  9. Selecting and targeting animals for system and marketing weights in this way will reduce inefficient feed use and help to maximise profit by reducing feed costs.

Storing Cattle

Cattle are normally stored in the winter in order to be grazed the following season. This sounds pretty obvious, but the main object in storing cattle is to take advantage of the extra compensatory growth from the highly digestible high value spring grass.
This is very desirable since the grass is much cheaper and more effective for finishing cattle, than the conserved winter forages on their own. Feeding cattle too well in the winter generally depresses the gains from grass later on.

Table 4

Target over wintering (Store) cattle gains.

Daily liveweight gain
Summer/Autumn born dairy bred calves. 1st rearing winter. 0.8 Kg per day.
Suckled calves/store cattle for grass finishing. British breeds & crosses. 0.4 to 0.6 Kg per day.
Continentals & crosses. 0.6 to 0.8 Kg per day.

Nutritional Requirements

The construction of rations for suckler beef relies on essentially the same information required for all ruminants.

  1. The liveweight of the animal.
  2. The targeted level of production. (daily liveweight gain)
  3. The type of production required. (growth, finish)

Once these parameters have been assessed the ration nutrient requirements essential to produce the target level of performance need to be calculated.

  1. Dry Matter Intake.

The calculation of this figure has been the subject of much debate. It is derived from the liveweight, body condition, breed, sex, chosen feeding system, general digestibility, palatability, forage quality, and amount of concentrates; and the way all of these interact.

As a rule of thumb, the figures in Tables 5a to 5e should be used.

Table 5a

Dry Matter Intakes of Growing Cattle

Dry Matter Intake Percentage Variation
100Kg 2.2 up to plus or minus 20%
300Kg 5.7 up to plus or minus 25%
500Kg 8.6 up to plus or minus 25%

Table 5aa

Modified to 2.10% body weight (Jerry Trowbridge 2001/2020)

Dry Matter Intake Percentage Variation
100Kg 2.1 up to plus or minus 10%
300Kg 6.3 up to plus or minus 15%
500Kg 10.5 up to plus or minus 20%

Table 5b

Modified to 2.10% body weight (Jerry Trowbridge 2001/2020)

Hay and Straw

Hay Straw Concentrates
ME (MJ/Kg DM 10 9 8 7.5 6.5 12.5
Liveweight (Kg) Feed intake (Kg DM per day)
100 2.5 2.3 2.1 2.0 1.8 2.9
200 4.6 4.2 3.8 3.6 3.2 5.1
300 6.3 5.7 5.1 4.8 4.2 7.2
400 7.7 6.8 6.1 5.7 5.0 8.7
500 8.9 7.8 6.9 6.4 5.5 9.5
Reduction of forage DM per Kg Concentrate DM (Kg) 0.6 0.5 0.4 0.2 0.2

Cattle feeding from trough

Table 5c

Feed intakes for growing cattle fed to appetite

Grass and maize silages

Maize Silage
ME (MJ/Kg DM) 11 10 9 11
Fermentation Good Poor Good Poor Good Poor
Liveweight (Kg) Feed intake (Kg Dry Matter per day)
100 2.6 2.3 2.4 2.1 2.2 1.9 2.7
200 4.8 4.2 4.4 3.9 4.0 3.5 5.0
300 6.6 5.8 6.0 5.3 5.4 4.7 6.9
400 8.0 7.0 7.4 6.5 6.4 5.6 8.4
500 9.1 8.0 8.6 7.5 7.2 6.4 9.7
Reduction in forage DM per Kg concentrate DM (Kg) 0.6 0.5 0.5 0.4 0.4 0.3 0.6

Note:
We have seen cases of growing cattle being able to consume up to 12.5 Kg DM on easy access maize and grass silages where the presentation is good and the trough space per beast is adequate.

Unless ad-lib feeding is available, adequate space should be provided for all stock to feed simultaneously. This will prevent more dominant animals bullying more timid animals. Pregnant cows should be allowed extra space.
Table XX shows minimum feeding space requirements for different weights of cattle for both ration fed stock and stock fed ad-lib. We would suggest a slightly more generous allowance.

Table XX

Mass of animal(kg) Ration fed, Feed barrier width (mm/animal) Ad-lib fed, Feed barrier width (mm/animal)
200 400 150
300 500 150
400 550 190
500 600 240
600 670 280
700 700 320
800 800 340

Feed intakes for suckler cows are very closely linked to forage quality. Good quality silage may have to be limited to prevent cows from getting too fat.

Table 5d

Dry matter intakes for suckler cows

(Grass Silage)

ME (MJ/Kg DM) 11 10 9
Fermentation Good Poor Good Poor Good Poor
Liveweight (Kg) Feed intake (Kg Dry Matter per day)
Lactating Cows
450 9.5 8.5 8.8 7.8 8.1 7.2
550 11.6 10.3 10.7 9.5 9.9 8.8
650 13.7 12.2 12.7 11.3 11.7 10.4
Dry Cows
450 8.6 7.7 7.7 6.8 6.8 6.1
550 10.5 9.5 9.4 8.4 8.3 7.4
650 12.4 11.2 11.1 9.9 9.8 8.7
Reduction in forage DM per Kg concentrate DM (Kg) 0.5 0.4 0.3 0.2 0.2 0.1

Table 5e

Feed intakes for suckler cows

(Hay and Straw)

Hay Straw
ME (MJ/Kg DM) 10 9 8 7.5 6.5
Liveweight Feed intake (Kg Dry Matter per Day)
Lactating Cows
450 9.0 8.1 7.4 6.7 6.1
550 11.0 9.9 9.1 8.3 7.4
650 13.0 11.7 10.7 9.8 8.8
Dry Cows
450 8.1 7.4 6.8 6.1 5.6
550 9.9 9.1 8.3 7.4 6.9
650 11.7 10.7 9.8 8.8 8.1
Reduction in forage DM intake per Kg concentrate DM (Kg) 0.5 0.4 0.3 0.2 0.2

Energy Sources for Beef

The use of bought in feeds to supplement the forages fed to beef animals is fascinating. The industry has been able to use a large portfolio of human food industry by-products which are often fed to pigs but can also be fed to intensive beef and finishing diets.

Sucklers may have access to a little concentrates around calving but they tend to be reliant on grazing and or mineral buckets or feed blocks. This suits the extensive systems very well and the upland and hill breeds will thrive on a forage system.

The only issue I have ever had with this is with farmers who seem to think that it’s okay to place a feeding ring in a field and allow a foot or so of “mud” to accumulate around it and watch their stock trudge through the morass in order to get a few mouthfuls of big bale silage!

Cattle stood in muddy field

It is a very damaging public image of farming.
It would be far better if they kept moving the ring feeder and allowed clean access to the silage. This would be better for feet and general health and performance; it would also do a great deal to clean up the public image of livestock farming.

Moving on!

The finisher diets and intensive beef diets can use many sources of by-products or they can be traditional.
The barley, soya-based diets are a great benchmark for many farmers and rely on the real quality of the barley and correct addition of a good mineral supplement.

Where some larger units can justify full articulated lorry loads of feed to be brought in, these can be great value for money provided the wastage is kept to a minimum.
Moist feeds in particular tend to ferment and spoil rapidly, The mycotoxin loading from these rotting heaps of feed can be very detrimental to performance and for that reason we strongly advise that farmers using moist feeds should include a good mycotoxin binder in the mix.

Dry feed by-products do not pose the same degree of mould risk (but they are not immune!).
The availability of blended sweet mixes based on bakery and confectionery waste is quite common and can offer good value provided they are balanced with the correct level and quality of protein.

The guidelines for starch and sugar in intensive grower and finisher diets recommend high levels and as a result the rumen can lapse into acidosis at a sub-clinical level as a matter of normality.
We suggest that when these diets are fed, the integrity of the rumen villae is compromised and the absorption of nutrients via the rumen wall is much less efficient.
The overall attraction of the high starch diet is rapid finishing and high energy density relying on large intakes to compensate for lower feed conversion efficiency.

This inherent weakness in the intensive system can be greatly improved by using plenty of structural fibre like chopped straw and chemical buffers along with a yeast all of which have great trial work to prove their effectiveness and financial return.

Energy Requirements for Beef & Suckler Cows

In the UK we use a system known as the Metabolisable Energy system (ME) system.
Energy requirements are based on units of Energy called Megajoules.
These are the equivalent of calories in human nutrition. In order for a ration to be constructed we need to know the daily ME requirements to support the level of performance of the animal and, also the ME contents of the feeds.

There are many publications which give the nutrient values of feeds. Most of them quote the Agricultural Research Council (ARC or NRC) National Research Council (USA) data, upon which most of the industry in the UK bases its rationing activity.

There is a bit of a dilemma in estimating the level of energy required this is due to the fact that the efficiency with which energy is utilised increases as the energy concentration in the diet increases!

In order to avoid hours of tedious calculations, many nutritionists let the computer software do all the tedious work and derive the ration the easy way.

A simple approach is to use the published data and adjust the diet by targeting a total ration energy density.

The energy density or M/D is the number of Megajoules per Kilo of Dry Matter of the diet.
Using M/D allows us to calculate the total amount of energy just by multiplying by the estimated total dry matter intake of the animal (from tables 5 a to 5 e).

For example:- (see page 14)
A 400 Kilo growing animal fed on good 11 MJ/Kg DM silage
It will consume 8.0 x 11 MJ = 88 MJ

So, if that hasn’t induced a deep sleep by now, you will be relieved to know that since all the hard work has been done, all we have to do is check the relevant tables.

The table below shows a generalisation of how the M/D will relate to various performance levels in differing types of cattle.

Table 6

Final ration M/D and its effect on performance (adjusted figures)

Designation Cattle Types
A Continental breed / cross bulls.
B Continental breed / cross steers & British breed / cross bulls.
C Continental breed / cross heifers & British breed / cross steers & Friesian / Holstein bulls.
D British breed / cross heifers & Friesian / Holstein steers.
E Friesian / Holstein heifers.

Table 6a

Growing and finishing cattle

Cattle Type > A B C D E
Daily Gain (Kg) Predicted ration energy density (M/D) expressed as MJ ME/Kg DM*
0.6 N/A N/A 10.4 10.5 10.6
0.8 N/A 10.7 10.8 10.9 11.0
1.0 11.2 11.3 11.4 11.5 11.6
1.2 11.4 11.5 11.6 11.2 N/A
1.4 11.6 11.8 12.0 N/A N/A
1.6 12.0 N/A N/A N/A N/A

* – Megajoules of metabolisable energy per kilogram of dietary dry matter.
N/A – Not applicable to this type of cattle.

The figures quoted here are at variance with some other sources of published data.
I have found that certain guidelines have proved somewhat optimistic.

For example:-to gain 0.9 kg per day:
a 400 Kg Continental cross bull needs 78 MJ.**
a 400 Kg British breed cross bull needs 83 MJ***
a 400 Kg Friesian / Holstein bull needs 88 MJ****

** Equivalent to 7.5 Kg dry matter at 10.4 MJ > Corrected to 7. 2 Kg DM at 10.8 MJ
*** Equivalent to 7.5 Kg dry matter at 11.0 MJ > Corrected to 7. 5 Kg DM at 11.0 MJ
**** Equivalent to 7.5 Kg dry matter at 11.7 MJ > Corrected to 7. 8 Kg DM at 11.3 MJ

Note: In reality the higher the M/D the higher the intake so the corrected figures are actually closer to reality.

Table 6b

Suckler Cows

Predicted ration energy density (M/D) MJ ME/Kg DM
Early lactation 10
Late lactation 9
Dry 8

There will be considerable variation in theses figures. Multi Sucklers need much higher density diets up to 11 MJ ME/Kg DM.

The efficiency of energy use is shown clearly by the example on page 13 Continental breeds and crosses are the most efficient, British breeds and crosses are intermediate and the Holstein Friesian cross is the least efficient.
AFRC requirements published in 1990 seem to result in some extreme variations in the calculated energy requirements of some bulls and heifers, in housed or outdoor systems.
I am in broad agreement with the guidelines published by Dr David Allen in 1992. The tables shown below are a useful and practical guide to determining the energy requirements for all beef systems practised in the UK.
The tables do not allow for the effects of compensatory growth in turned out store cattle or for the effects of growth promoting enhancers, like selected yeasts. I have varied some of the figures after reviewing some recent publications generally they are adjusted slightly up.

Table 7

ME requirements of growing cattle (Modified from AFRC)(JJT 2020)

Table 7a

Continental breed/cross bulls

MJ ME per day at a daily gain in Kg of:
Live-weight Kg Ration M/D 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6
100 11 32 34 37
12 30 32 34 36 39 42
13 28 30 32 34 37 39 42 45
200 10 49 53
11 47 51 54 56 62 65
12 44 47 50 54 58 63 66 70 75
13 54 58 62 66 71
300 10 65 69 75
11 62 65 69 74 79 85 91
12 62 66 71 75 79 85 90 96
13 69 74 79 84 90
400 10 78 85 91
11 74 79 84 90 96 103 111
12 75 80 86 91 97 103 110 117
13 91 97 102 109
500 10 92 98 105
11 88 93 99 105 113 121 129
12 89 95 100 106 113 120 128 137
13 106 112 119 127

Table 7b

Continental breed/cross steers, and British breed/cross bulls

MJ ME per day at a daily gain in Kg of:
Live-weight Kg Ration M/D 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4
100 10 30 33
11 29 31 34 36
12 28 30 33 35 38 41 45
200 10 46 49 53 57
11 45 48 51 55 59 64 69 75
12 46 49 52 55 59 63 68 73
13 49 53 56 60 64 68
300 9 63
10 60 65 70 75
11 57 61 65 70 75 80 87 93
12 62 66 70 75 80 86 92
13 70 75 80 85
400 9 75
10 72 77 83 90
11 69 74 79 84 90 98 105 113
12 75 80 85 92 98 106 112
13 92 98 105
500 9 88
10 84 90 96 103
11 80 85 91 97 106 113 122 131
12 88 94 100 106 116 121 130
13 107 114 122

Missing figures on the tables are, at the higher gains, above the normal potential daily liveweight gains for the type of animal and at the lower gains, below the normal range of typical dry matter intakes.

Table 7c

Continental breed/cross heifers, British breed/cross steers

Friesian/Holstein bulls

MJ ME per day at a daily gain in Kg of:
Live-weight Kg Ration M/D 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
100 10 29 32
11 27 29 32 35 38
12 28 30 33 36 39 42 45
13 28 31 34 37 39 42 45
200 10 41 48
11 43 47 50 55 59 64 70
12 51 55 59 64 69 75 81
13 52 57 61 65 69 75 82
300 9 60 65
10 57 63 67 73
11 56 60 65 69 77 80 88 97
12 62 67 72 77 85 91 98 105
13 72 77 85 91 98 105
400 9 73 79
10 70 75 81 88
11 66 73 77 85 91 98 108 116
12 74 80 86 92 99 106 119 129 140
13 93 100 107 118 125
500 9 84 91
10 81 87 94 103
11 78 83 90 97 104 119 130 141
12 86 96 100 106 118 130 140 151 162
13 108 115 124 133 143

Table 7d

British beef/cross heifers and Friesian/Holstein steers

MJ ME per day at a daily gain in Kg of:
Live-weight Kg Ration M/D 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3
100 10 29 32
11 29 32 35 38
12 28 30 32 36 39 43
13 30 32 35 37 41 45
200 10 46 49
11 44 47 52 56 62 68
12 46 50 54 58 63 68 76 80
13 55 59 64 68 75
300 10 59 68 71 78
11 52 68 73 79 86 95
12 64 69 75 80 86 93 101
13 71 76 81 87 95
400 10 72 77 85 93
11 69 75 82 88 96 104 114
12 72 78 83 91 97 105 113 124
13 91 98 105 114
500 10 84 91 99 109
11 80 87 94 101 111 120 131
12 84 90 97 104 112 121 131 143
13 106 112 121 131

Table 7e

Friesian/Holstein Heifers

MJ ME per day at a daily gain in Kg of:
Live-weight Kg Ration M/D 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
100 11 30 33 36
12 29 31 35 38 41 45
13 28 31 34 36 40 44 47 51
200 10 47 52 57
11 46 50 55 60 66 74
12 48 52 57 61 67 74 80
13 54 59 64 69 75
300 10 62 68 74
11 60 65 72 77 85 93
12 62 67 74 80 86 94 103
13 75 81 87 95
400 10 75 82 92
11 72 78 86 94 104 115
12 75 81 88 96 104 114 125
13 89 97 105 114
500 10 87 95 105
11 84 92 100 109 119 130
12 87 95 104 113 122 132 143
13 105 113 121 132

Cattle feeding from trough

Protein Requirements

Protein is the stuff that meat is made of. The growth of the animal is governed by the relationship between the amount and type of energy in the diet and the amount and type of protein.

There are essentially two types of protein:- Effective rumen degradable protein (ERDP) ( the bit that the rumen bugs can use in order to make more rumen bugs), and Un-degradable protein (UDP)(the protein that doesn’t get degraded in the rumen).
The ERDP fraction generally contains some Non protein Nitrogen (NPN) which is also a potential protein building block for the little rumen microbes to use.

It is important to balance this ERDP with an appropriate source of energy. This energy has to be able to be used by the rumen microbes, ideally at the same rate as they can use the ERDP. The energy is referred to as fermentable energy or FME. The FME is made up of different carbohydrates like sugar, starch, and cellulose from the crude fibre in the diet.

The proportion of ERDP in the ration is directly related to the amount of FME required to utilise it and has been set by the AFRC back in 1992 at 10 grams per Megajoule of fermentable energy in the dietary dry matter. This is still a reasonable guide in 2020.

Without going into detail here, it is important to remember that energy and protein is co-reliant, so when we construct the diet, we have to bear in mind that it is not enough to simply supply enough energy. The best diets will supply enough energy of the right types to optimise the metabolism of the protein in both the rumen and the hind gut.

In order to keep life simple Table 8 shows the requirements of protein for growing cattle to be matched with the energy density of the diet.
In the light of experience my figures are at slight variance with some of the published data. I have found that growing animals actually grow better if the protein contents are a little higher than normally recommended.
This can be easily borne out by comparing the performance of growing stock at the same age on spring grass at say 18% to 22% crude protein and indoor silage-based diets typically at 13% to 14% crude protein.

As a rule of thumb, the list below seems to work really well:

• 0 weeks to weaning Milk plus 18% CP pellet or coarse mix creeps fed dry.
• Weaning to 200 Kg Forage plus a 16% pellet or blend to average 16% in the total ration.
• 200Kg to 350 Kg Forage plus a 15% pellet or blend to average 15% in the total ration.
• 350Kg to finisher diet Forage plus a 14% pellet or blend to average 14% in the total ration.
• Finisher diet Forage plus a 12% pellet or blend to average 12% in the total ration.

These diets work well but for Holsteins it works better at one percent less protein from start to finish and extra energy density if possible.

Table 8a

Crude protein requirements for growing cattle (college notes)

Ration energy density (M/D)( Megajoules per kilo of dry matter)
9 10 11 12 13
Liveweight Crude Protein content of the dry matter of the total ration (%)
100 18 21 24
200 14 14.5 15.5 16.5
300 13 13.5 14 15 15.5
300+ 12 13 13.5 14 14.5

There are some modifications that can be made to the data in table 8 a. UK breeds can require around 1% less crude protein than the stated values although this should be reviewed against actual performance rates of growth. Check weighing at regular intervals is recommended good practise for all growing cattle in order to make any adjustments necessary to keep to the targeted performance levels.

Table 8b

Protein requirements for housed Suckler Cows (college notes)

Daily weight change (Kg) Milk Yield (Kg) Crude Protein
(Percentage of DM)
Spring Calvers
Pre-calving 0.50 0 14
Suckling -0.50 10-15 15-16
Autumn Calvers
Suckling – Bulling -0.25 10-15 15-16
After Bulling 0.50 7-12 15

Rations for suckler cows will usually supply excess protein especially with cows fed on spring grass and good dairy type silage.
Cows will use energy to remove excess protein out of the body, although most cows are left to graze grass, they have evolved to generally cope with much poorer forage than the farmed pastures that they experience today.
Modern grass pastures have grass varieties that have been bred for productivity and these should be balanced with rougher herbage at the times of the year when they are too high in protein and low in fibre. (Spring and early autumn).

Minerals for Beef

The main mineral requirements for beef cows are similar to those of dairy cows. Sucklers are susceptible to staggers since they are generally fed less concentrates and, in the case of upland beef, tend to be reared on poor pastures.
It is advisable for these farms to dose with boluses or feed mineral supplements.
Male animals and steers (castrates) should not have access to Magnesium or Phosphorous since these two elements predispose Urinary Calculi (Stones) which eventually block the urethra and prevent the animal from passing urine, the effect is normally fatal.
Most beef should get plenty of calcium, salt, copper, selenium, and vitamin E. It is advisable
to check the mineral status of the diet ingredients first and then buy a balancing supplement.

What We Need To Know

System Data

Single Multi
Suckler System
All Year Round Spring Autumn
Calving Pattern
UK Continental Cross
Breed (Dam)
Breed (Sire)
Silage 2nd Forage Straw
Forage
Quality
Intensive (Cereal) Semi-Intensive (Silage) Extensive (Grass)
Desired Beef System
Growing
Storing
Finishing

What We Need To Know

Animal Data

Sex Bull Heifer Steer
Liveweight Kg
Target Daily Liveweight Gain Kg per day
Or
Stage of lactation (Daily milk yield) Litres
Feeding system restrictions
Silage 2nd Forage Straw
Forage quality analysis
Straights Concentrates Succulents
Suitable Feed Supplements (Analysis)
In Feed Ad Lib Blocks/Boluses
Minerals

Today we can use powerful rationing software on our laptops and tablets to do the diet formulation calculations for us. This text has endeavoured to explain some of the thinking behind these models and allow us to have a better understanding of the diets that are put in front of us.

JJT 2020
© Copyright LSFS Ltd 2020