Ration Formulation

Question 1

What is the first step in ration formulation?

Answer 1

A horse must be weighed

Question 2

What are different methods for gaining an estimate of a horse’s weight?

Answer 2

Weightbridge, weighttape, calculation of weight from formula

Question 3

What are different formulas for weight?

Answer 3

1. Leighton Hardman (1981) -
   (heartgirth² x length)/ Y
   The Y factor varies - there is one for TBs and one for others
2. The Henneke System -
   9 point scale based on the optimum weight of broodmares. To conceive, they should be slightly underweight
3. Caroll and Huntington (1988) -
   A 5 point scale measuring body condition. 0 is emaciated and 5 morbidly obese.
   (heartgirth² x length)/ 11877 (or 12265 or 11706)
4. Kienziele and Schramme (2004) -
   A system aimed at WBs. Based on the 9 point Henneke scale

Question 4

What are the main considerations for diet composition?

Answer 4

• digestive health
• heat increment
• glycaemic response + the excitability effect

Question 5

What should the roughage:concentrate ratio be?

Answer 5

A minimum of 50:50, ideally with more forage

Question 6

What happens if there are more concentrates than forage consumed?

Answer 6

• gastric distension (enlargement of the stomach)
• poor HCl penetration into stomach contents
• poor protein digestion (to polypeptides)

Question 7

What is digestible energy?

Answer 7

Most important part of the diet. The metabolic rate affects how much energy the horse needs for maintenance.
It is calculated in MCal using bodyweight.

For good doers: 0.0303 x BW
Average doers: 0.0333 x BW
Poor doers: 0.0363 x BW

Question 8

Define MAINTENANCE ENERGY

Answer 8

Maintenance energy is the energy that the horse requires to fulfil its bodily functions (i.e. to survive)

Question 9

How should overweight horses be managed?

Answer 9

• weight loss programme needs to include exercise
• starvation paddocks should be avoided
• long soaking hay to remove sugars is a good idea
• some dry matter may be lost when hay is soaked however

Question 10

Define a METABOLIC RATE

Answer 10

The metabolic rate is the total amount of energy that a horse uses in a unit of time.

Question 11

How much forage should be fed to gain weight? To maintain weight? To lose it?

Answer 11

To gain - 2.5% of LW
To maintain - 2% of LW
To lose - 1.5% of LW

Question 12

How are the different requirements of energy calculated?

Answer 12

Work energy = Mcal/hour of work/100kg +DE maintenance level
CP maintenance = 40 x MCal DE/day
Lysine = 0.035 x gCP/day
Calcium = 1.22 x MCal DE/day

Question 13

How should underweight horses be managed?

Answer 13

• exercise should be monitored to allow the adaptation of bone and muscle
• needs to have sufficient energy for maintenance plus workload
• risk of muscle wastage to accommodate protein if the horse is truly energy deficient