Transcript Ration formulation

CALCULATING A
FEED RATION
Factors to consider
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Present state of condition and health.
Size and type.
Age.
Weight.
Amount of work.
Temperament.
Ability of rider.
Weather (horse in / out?).
Cost-effectiveness.
Availability of foodstuffs.
Feed storage and ease of handling.
Assessing condition in horses
• The horse’s condition can be described as
GOOD or BAD.
Soft
• Good condition
Hard
• Bad condition
Underweight
Overweight
• Good condition - Carrying an appropriate
amount of weight for the stage of training or
work required. Thriving appearance. Signs of
good health.
• Soft - Well but not fit. Slack muscles.
Slightly fat but not unhealthy. Incapable of
sustained effort without sweating / distress.
e.g. turned away / post injury.
• Hard - Well and fit. Free from excess fat
(internally & externally). Muscles hard / well
developed and clearly defined. Limbs toned.
e.g. hunter in regular work / competition
horse.
• Bad condition - Not carrying the correct
amount of weight for the work required. Not
thriving.
• Underweight - No layer of fat under skin.
Underdeveloped muscle. Neck, shoulders,
quarters very thin. Bones prominent. Skin /
coat dry & dull. Lacking energy. Cannot fight
infection or withstand the cold.
• Overweight - Gross, pads of fat. Neck, crest,
shoulder, quarters. Moving is an effort
leading to distress. Internal organs are
covered in fat, causing excess strain. Limbs
suffer due to extra burden.
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Gross / Obese =
Light =
Poor =
Emaciated =
Fat
Short of ideal
Short of flesh, dull coat
Skin and bone
• Condition is assessed by using the “condition
scoring” system.
• This measures the weight distribution over
the neck, back, ribs and quarters.
Step 1. Calculating the
horse’s weight
• How big is the horse? Either measure or estimate.
• Ideally, use a weighbridge.
• Weightapes – measure around the girth and they give an
approximate weight.
• Formulae - Girth & body length measurements – measure around
the girth (G) & from the point of shoulder to the point of hip (L)
and use the following equation:
• G(cm) x G x L(cm) = Bodyweight (kg)
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• G(in.) x G x L(in) = Bodyweight (lb)
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or
Table of approximate bodyweights:
Type
Height
(h.h.)
Approx.
weight (KG)
Approx.
weight (lb)
Pony
13.0
300
660
Large pony
14.2
425
950
Small hunter
15.2
500
1100
Medium
hunter
Large hunter
16.0
575
1250
16.3
650
1500
Draft /
shire
17.0
1000
2200
Step 2. Calculating
total daily feed requirement
• A horse can eat up to 2.5% of its bodyweight daily,
although it does not have to eat the maximum.
• Calculation used:
• Bodyweight (kg) x 2.5 = Max. daily amount of food kg
100
• For example – a 15.2hh small hunter weighs approx.
500kg.
• 500 x 2.5 = 12.5kg (28lbs) (to convert kg to lbs x 0.25)
100
• Quantity then needs to be adapted to suit the
individual & the circumstances.
Step 3. Roughage:
concentrate ratio
• Total daily feed
intake is split into
the hay / haylage /
grass ration & the
concentrate ration.
• Based mainly on the
horse’s workload.
Work done
Roughage
Concentrates
Resting
100%
0
Light work
80%
20%
Medium work
65%
35%
Hard work
50%
50%
• The percentages then
have to be converted
into weights of feeds.
• For example, the 500kg
horse being fed 12.5kg
food / day.
• If being fed 75:25% R:C
• 12.5 / 100 x 75 = 9.38kg
roughage / day
• 12.5 / 100 x 25 = 3.13kg
concentrates / day
EXERCISE
• Individually, work out a ration for your own horse or
one that you care for.
• State the height & type & estimate the weight.
• State the work done & temperament etc.
• Calculate the total daily feed requirement & roughage
: concentrate ratio.
• Calculate the weights of the roughage &
concentrates.
• Suggest suitable types of feed & forage.
Step 4. Protein requirements
• Suggested protein levels in the total ration:
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Light work
Medium work
Hard work
Strenuous work
7.5
7.5
8.5
8.5
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8.5%
8.5%
10%
10%
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Pregnant mares
Mares in last trimester
Lactating mares
Foals
Weaned foals
Yearlings
2 year olds
3 year olds
8 – 10%
11-13%
14 – 12% (gradually decreasing)
16-18%
14.5 – 16%
12-14%
10 – 12%
8.5 – 10%
Step 5. Calculating digestible
energy requirements
• Maintenance
• Horses need 18MJ plus an extra 1MJ for each 10kg
of bodyweight.
• 18MJ
+
bodyweight (kg)
10
• e.g. a 500 kg horse
• 18 + 500 = 68 MJ of DE / day
10
• Production
• For work, add 1-8MJ for each 50kg of bodyweight,
according to how hard the horse is working.
• Work score x bodyweight + maintenance DE
50
• e.g. a 500 kg horse in medium work (some cantering):
• 3 x 500 = 30MJ + 68MJ DE = 98MJ of DE / day
50
• (Add extra MJs for lactation, pregnancy and growth.)
Scale points for level of work
Category
Light work
Medium work
Hard work
Fast/ energetic
Scale point
Activity
1
1 hour walking
2
Walking & trotting
3
Some cantering
4
Jumping, schooling, dressage,
driving
5
Eventing, cross-country, driving,
hunting, endurance
6
Hunting 2 days / week, 3-day
eventing
7
Racing
8
Racing
Step 6. Allocating feed types
• You have calculated the daily intake, the roughage:
concentrate ration, and the energy requirements.
• You now have to decide on what types of feeds to
give.
• Start with the roughage. Use this as your base and
try to give the energy requirements as closely as
possible through the roughage.
• Any shortfall can then be made up with the
concentrate portion of the ration.
• Does the horse need high energy or low energy
foods?
• Does the horse need quick releasing or slow releasing
energy?
EXERCISE: Suggest a suitable daily diet for a
14.2hh horse doing 1 hour of walking / day:
Feed type
Quantity
e.g.
fed kg / day
Hay
DE / kg
Haylage
Cool mix
Hi-fi
Sugar beet
Total DE /
day in diet:
DE total
MJ / day
EXERCISE: Suggest a suitable daily diet
for a 16hh horse hunting twice a week :
Feed type
Quantity
e.g.
fed kg / day
Hay
DE / kg
Haylage
Total DE /
day in diet:
DE total
MJ / day
EXERCISE: Suggest a suitable daily diet
for a 15hh race horse:
Feed type
Quantity
e.g.
fed kg / day
Hay
DE / kg
Haylage
Total DE /
day in diet:
DE total
MJ / day
EXERCISE: Suggest a suitable daily diet for a
15.2hh horse doing schooling & dressage:
Feed type
Quantity
e.g.
fed kg / day
Hay
DE / kg
Haylage
Total DE /
day in diet:
DE total
MJ / day
Step 7. Reconciling the ration
• If the total DE content of the daily diet far exceeds
the horse’s requirements, or vice versa, you could
manipulate one or more of the following:
• Maximum daily appetite from 2.5% of bodyweight to
as little as 2% of bodyweight.
• Roughage : concentrate ratio.
• Choice of feed types.
• Proportions of different feeds (particularly
concentrates).
• Workload.
Step 8. Monitoring
• Ongoing monitoring of the horse’s
response to its diet is vital (i.e.
condition scoring), to gauge whether she
is loosing / gaining weight or maintaining
a desirable body condition.
• The diet can then be manipulated to
take the response into account.