What is the first step in ration formulation?
A horse must be weighed
What are different methods for gaining an estimate of a horse’s weight?
Weightbridge, weighttape, calculation of weight from formula
What are different formulas for weight?
- Leighton Hardman (1981) -
(heartgirth² x length)/ Y
The Y factor varies - there is one for TBs and one for others - The Henneke System -
9 point scale based on the optimum weight of broodmares. To conceive, they should be slightly underweight - 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) - Kienziele and Schramme (2004) -
A system aimed at WBs. Based on the 9 point Henneke scale
What are the main considerations for diet composition?
- digestive health
- heat increment
- glycaemic response + the excitability effect
What should the roughage:concentrate ratio be?
A minimum of 50:50, ideally with more forage
What happens if there are more concentrates than forage consumed?
- gastric distension (enlargement of the stomach)
- poor HCl penetration into stomach contents
- poor protein digestion (to polypeptides)
What is digestible energy?
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
Define MAINTENANCE ENERGY
Maintenance energy is the energy that the horse requires to fulfil its bodily functions (i.e. to survive)
How should overweight horses be managed?
- 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
Define a METABOLIC RATE
The metabolic rate is the total amount of energy that a horse uses in a unit of time.
How much forage should be fed to gain weight? To maintain weight? To lose it?
To gain - 2.5% of LW
To maintain - 2% of LW
To lose - 1.5% of LW
How are the different requirements of energy calculated?
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
How should underweight horses be managed?
- 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
