Horses Flashcards
What are the feeding behaviours of horses?
High gut fill
16-17hrs a day grazing
Ingest more food/unit BW than ruminants.
Spend less time chewing.
Peak grazing times early am and late pm, bouts last 30mins to 4hrs.
Grazing is not dependent on feed availability and will consume beyond their needs - evolutionary sense to lay down fat reserves.
Prefer young growth and leaves, graze shorter grasses than ruminants.
Do concentrates or fibres increase the chewing in horses?
Hay has 4 x more chewing than oats (also takes 4 x longer to eat).
What foods enhance saliva production? Why is this important?
Hay has most, then grass, then mixed feed.
Important for bicarbonate (buffer).
Decreased fibre - decreased chewing - decreased saliva - less buffering - more gastric acidity - more ulceration - more stereotypies.
What is neophobic?
Fear of trying new feeds - horses on well balanced diet are reluctant to try different feed stuffs.
What influences food intake?
Taste, smell, visual appraisal, texture, aversions formed when illness immediately follows ingestion.
Voluntary feed intake increases when indigestible fibre present in feed.
What macronutrients does a horse require?
Water
Energy - carbohydrates (glucose, VFA’s)
Lipids - triglycerides, FFA’s
Protein - AA (essential and limiting)
What micronutrients does a horse require?
Macrominerals
Microminerals - trace minerals, trace elements
Vitamins - water and fat soluble
What is the most limiting nutrient after water that a horse requires? Discuss this?
Energy.
Primary source is nonstructural CHO (starch, maltose, sucrose), digested in SI and stored as muscle glycogen.
Structural CHO - cellulose, hemicellulose, pectin. Fermented in caecum to VFA’s.
What factors influence the energy requirements of a horse?
Stage of life Body composition Environment - temp., humidity Intensity and duration of work Weight and ability of rider Condition of working surface/terrain Degree of fatigue
What are the maintenance requirements of a 500kg horse?
DE = 68.5MJ/day
How do you determine DE for a horse?
DE (Mcal/d) = 1.4 + 0.03W
W=weight
to convert to MJ x4.18
What challenges are associated with feeding maiden and barren mares?
Don’t want them to get to fat (above 3,3.5/5 BCS).
Rising plane of nutrition for joining (6wks prior).
What nutritional considerations need to be taken into account when feeding a mare in the last 3rd of gestation?
Last 3 months - rapid growth of foetus (500g/d)
Energy, protein, Ca and P requirements increase.
Lay down fat for lactation.
Intake problems - capacity of GIT.
At what life stage is a horses nutrient needs the highest?
During lactation.
Recovering from parturition and producing milk.
3% BW produced in milk per day in first 3 months.
Body condition suffers before milk production.
How many MJ DE are required to produce 1kg of milk?
3.3MJ DE
What are the requirements of a breeding stallion?
No special requirements.
Maintain good body condition with their increased physical activity.
Extra energy and protein if workload warrants it.
Some evidence that increased omega-3 FA in diet assists sperm quality in stallions with poor transport quality semen.
How much more energy do grains have than hay?
40-60% more
What are some ways to increase energy density?
Feed higher quality hay
Add grain
Substitute grains/concentrate by adding fat (up to 15% by weight)
What are some problems associated with the feeding of excess energy?
Excess body weight
Laminitis
Behavioural problems
Thermal stress
What should obese horses be fed?
Grass hay 1.5%BW
Divide into 2 meals, soak for at least 8hrs to remove WSC.
Balanced vitamin and trace mineral supplement - mix with low energy chaff.
Atleast 1hr/d exercise
Free access to water at all times
Fitted grazing muzzle if turned out.
How much protein should be fed for maintenance?
8%
12% for growing horse in work
Good quality lucerne - 15-20%CP
How much water can you expect a horse to drink?
2-3L/kg DM intake
Lost as urine, faeces, sweat, evaporation from lungs and skin, lactation.
Lactation has requirement 50-70% above maintenance.
What influences water intake?
Water to feed ratio
Increased hay = increased water intake
Temperature - decreased with decreased temp.
Work - increases 20-300%
What causes endotoxaemia?
Excessive consumption of readily fermentable CHO’s.
Inadequate adaptation to diet - rapid change in diet.
Accidental access to grain/concentrate.
What are endotoxins?
Lipipolysaccharides (LPS).
Structural component of gram -ve, non sporing rods of enterobacteriaceae (eg. E.coli)
Inhabit intestines.
Elicit strong immune responses in animals.
Clinical signs mediated by prostaglandins.
Inhibit gastric secretions and increase Na output.
Describe disease progression in the case of endotoxaemia.
Grain overload - increased lactobacillus & streptococci - produce lactic acid - drop caecal pH.
Starch fermenters proliferate faster than cellulose fermenters.
Organisms that utilise lactic acid not adequate - pH drops further.
Ciliate protozoa that normally engulf starch and act as buffers are killed by low pH
Normal homeostatic mechanisms are destroyed - acid production continues.
Enterobacteria die, releasing large amounts of LPS.
Colonic integrity compromised.
Intestinal ischaemia, abetted by lactic acidosis or previous parasitism.
Endotoxins overwhelm mononuclear phagocytic system that normally clears them.
