Equine 1 - Aimee Flashcards
What is the primary function of the mouth in digestion?
Mastication/chewing, reduce feed particle size, mix feed with saliva, starch digestion.
How much saliva is secreted per day?
Approx 40L/day, only secreted while eating.
List the relative sizes of the stomach, small intestine, cecum, and large intestine in horses from largest to smallest.
From biggest to smallest:
* Large intestine
* Small intestine
* Cecum
* Stomach
The stomach is relatively small compared to body size.
Where do microbial and enzymatic digestion occur in the GIT?
Enzymatic:
* Stomach
* Small intestine
Microbial
* Cecum
* Large colon
* Small colon
What enzyme is involved in starch digestion in the mouth?
Amylase
What are the main functions of the stomach in horses?
- Storage and physical mixing
- Initial chemical digestion
- Propel food to small intestines
- Protein digestion.
Protein digestion occurs here with the aid of HCl and pepsin.
What enzymes are involved in protein digestion in the small intestine?
- Trypsin
- Chymotrypsin
- Carboxypeptidase
What is the rate of passage in the small intestine?
Fast rate of passage
Where are the majority of carbohydrates digested and absorbed?
Small intestine
How much of the small intestine can be removed during anastomosis and resection?
Up to 75%
What nutrient types are digested in the small intestine?
- Protein
- Carbohydrates
- Fat
Main site of carbohydrate digestion.
What is the main function of the large intestine in equine nutrition?
- Fermentation vat
- Microbial breakdown of cellulose
- Water and salt absorption
- Reservoir for water and electrolytes
What is absorbed in the large intestine?
- Water
- Salt (Sodium Chloride)
The large intestine also serves as a reservoir for water and electrolytes.
What is the rate of passage in the large intestine?
Slow rate of passage
How much ingesta can the large intestine contain?
75-90kg
Important when treating colics because it is a misconception that if horses pass manure, they are not in colic. This is wrong! They can have up to 5 days of manure in the LI and can still pass it if obstruction is before LI.
What is the primary function of the small colon?
Water absorption and fecal ball formation
What are the main components that determine feed requirements for horses?
- Forage requirements
- Energy requirements
- Protein requirements
- Nutrient composition of feed
How many hours a day should horses ideally be eating?
15 hours a day
This is crucial for meeting their nutrient requirements.
True or False: Most of a horse’s nutrient requirements can be met with forage alone.
True, if it is a good quality forage.
How much pasture is required to graze one horse during the summer?
3-5 acres of good pasture
Adequate grazing land supports the horse’s dietary needs.
What is the average daily dry matter intake (DMI) for adult horses?
1.5% - 3.0% of body weight (2% avg) but depends on body condition!
For a 500 kg horse, this translates to about 10 kg dry weight of feed.
What is the minimum maintenance energy requirement for horses in kcal/kg body weight?
30.3 kcal/kg BW
This is the baseline energy needed for maintenance.
What is the average maintenance energy requirement for horses in kcal/kg body weight?
33.3 kcal/kg BW
What is the elevated maintenance energy requirement for horses in kcal/kg body weight?
36.3 kcal/kg BW
This may be necessary for horses with higher activity levels.
What factors are included in the maintenance energy requirement?
- Basal Metabolism
- Basic Activity
- Temperature Regulation
- Maintenance of weight
How much weight change is required to increase/decrease body condition by one score?
25 kg of weight
This change should occur gradually over 60-180 days.
How many Mcal above maintenance is required to increase body condition by 1 kg?
20 Mcal
TOTAL! Not per day lol
If a 500 kg horse is at a current BCS of 4 and desired BCS of 5, how much weight change is needed? How much additional energy is required for this change?
25 kg gain to change from a 4 to 5 BCS.
20Mcal x 25kg = 500Mcal of additional feed required TOTAL.
What is the basal daily energy maintenance (DEm) for a horse?
17 Mcal/Day (for a 500kg horse)
What happens if energy needs are not met in an animal?
The animal will burn protein for energy instead
Important to meet energy requirements before supplementing protein!
Is there any benefit to supplementing protein if energy requirements are not met?
No
Supplementing protein without meeting energy needs is ineffective.
What is the average digestible protein requirement for a 500kg horse?
500 g digestible protein, 10% protein in feed.
What percentage of protein is typically found in horse feed?
10% protein in feed
What is the maximum percentage of fat allowed in a horse’s total diet?
Max ~20% in total diet
How much fat can a 500kg horse typically handle?
500 ml of fat (just over 2 cups)
This is an efficient source of digestible energy.
How much energy does half a cup of fat provide?
1 MCal
What is the fat content in natural horse diets?
< 3-4% fat
What is the fat content range in ‘high fat’ concentrates?
6-10% fat
These concentrates are formulated to provide more energy.
Describe how omega 6 is metabolized.
Linoleic acid to arachidonic acid to prostaglandin E2
Prostaglandin E2 is an inflammatory mediator.
Describe how omega 3 is metabolized.
Alpha linoleic acid converts to EPA and DHA, which compete with prostaglandins to suppress inflammation.
What is the omega-6 to omega-3 ratio in flax oil?
1:5
Flax oil is particularly high in ALA, an omega-3 fatty acid.
What is the omega-6 to omega-3 ratio in marine oils?
1:3
Marine oils are a good source of DHA and EPA.
Which is pro-inflammatory and which is anti-inflammatory between Omega 3 and 6?
Omega 6 - Pro-inflammatory
Omega 3 - Anti-inflammatory
What is recommended for diets consisting only of forage?
A vitamin and mineral supplement
This is important because forages may not provide all essential nutrients.
What is the importance of salt in a horse diet?
It increases the amount of water a horse drinks / encourages more drinking.
What happens to hay as it ages?
It loses nutrient value, especially vitamins
What are two important nutrients to monitor in horse diets?
Vitamin E & Selenium
What are the essential functions of water in the body?
Essential for all body functions!
- Temperature regulation
- Feed digestion
What factors influence the amount of water intake for horses?
- Level of exercise
- Sweat losses
- Ambient temperature
- Quality of feeds in ration
- Proportion of diet that is forage
Inadequate water intake can lead to…
impaction colic (constipation)
What is the minimum water requirement for a horse per day?
50-60ml/kg/day = ~24L/day
This is a general guideline for hydration.
True or False: Eating snow is sufficient for a horse’s water intake.
False
What is the Thermoneutral Zone?
The range of temperatures at which metabolic heat production doesn’t change.
What happens below the lower critical temperature (LCT)?
Metabolic heat production increases, requiring more energy.
The LCT ranges vary for different age groups of horses.
What is the estimated time to acclimatize to a new environment?
21 days to ‘reset’ the Thermoneutral Zone.
Acclimatization is important for proper thermoregulation.
How much does cold weather affect the daily energy requirement (DE) for horses?
DE requirement increases 1.3-2.5% for each 1°C below LCT.
What is the LCT range for newborn and week-old foals?
Newborn: 16-26°C.
Week-old: 13-23°C.
What is the LCT range for adult horses?
-20 – +5°C.
What are the effects of heat on metabolic rate?
Increased energy requirements and main loss of heat through sweat.
Other factors include increased activity and electrolyte needs.
How does obesity affect heat stress in horses?
Obesity increases heat stress due to less circulation through adipose tissue.
What is the UCT range for adult horses?
20-30°C.
This is an estimate.
What is the heat increment of feeding?
Different feeds produce different amounts of heat.
What are the heat increments of different feeds?
Hay > Grain > Fat
Fibre > Protein > Starch > Fat
What factors affect nutritional needs?
- Size, body type and weight
- Age
- Work: production stage
- Breed: temperament
- Environment: climatic conditions
- Health status (external & internal parasites, dental disorders, systemic disease)
- Vices
What happens if energy needs of performance horses are not met?
Performance horses have increased energy requirements.
If energy needs are not met, the animal will burn protein for energy instead.
Performance horses need _______ as part of their diet.
[forage]
What are the feeding requirements for a stallion?
Similar to adult horse, adjusted for level of breeding activity
What is the ideal body condition score for stallions?
5 or 6 out of 9
What is the effect of supplements on stallions?
Provide varied and inconsistent results, limited to no changes in semen quality
What are the nutritional requirements for broodmares during early to mid-gestation?
Good quality forage + mineral supplement
What are the increased nutritional requirements at 5 months gestation for broodmares?
- Energy
- Protein
- Mineral
What is required for broodmares in late gestation?
Additional energy through concentrates, BCS 6+ as a buffer for poor feed conditions
What is the ideal body condition score (BCS) for foaling mares?
5-7
This score helps optimize conception rates and overall health.
When does the fetus grow the most?
In last trimester
How much body weight will pregnant mares gain?
12-15%
What percentage of body weight can a lactating mare produce in milk per day?
2–4% of her body weight
Lactation is very energy demanding!!
What happens to a lactating mare’s nutrient stores?
Mares will use nutrient stores to supply milk nutrients first
True or False: It is common to overfeed pregnant mares.
True
Overfeeding can lead to complications during pregnancy and foaling (dystocia).
What is the primary diet for a growing horse from birth to 3 months?
Primarily milk, starts eating what dam does within a week.
What is the primary diet for a growing horse from 4 to 6 months?
+ when is weaning?
Drop in milk consumption, increased forage and concentrates.
Weaning usually around 5 mo.
What is creep feeding and when should it start?
Creep feeding involves providing supplemental feed to foals while they are still nursing from their mothers.
Should start at 8 weeks of age.
What is the rule of thumb for creep feed intake?
Feed 0.45 kg per day for each month of age.
What are the goals of creep feeding?
- Accelerate digestive tract maturation
- Allow for consistent growth
- Decrease stress of weaning
- Provide adequate nutrients (if milk doesn’t)
Creep feeding helps in the transition from milk to solid food.
What strategies can help maintain growth rate around weaning?
- Introduce foal to concentrates and forages before weaning
- Wean foals onto the best quality forages available
- Supply additional supplementation in winter and cut back on dietary energy in spring
How does the diet of yearlings differ from that of weanlings?
Dietary nutrient concentrations for yearlings are less than that for weanlings.
Yearlings’ diet is more similar to that of an adult horse.
What is a key consideration in feeding yearlings?
Use nutrition to reduce drastic changes in growth rate.
This helps mitigate risks of developmental orthopedic disease (DOD).
What is an old horse?
Generally healthy and over 20 years old
What defines a geriatric horse?
Older horse with signs of senescent changes, may have concurrent disease.
What are some digestive changes in geriatric horses?
- Reduction in digestion and changes in microbial population
- Fiber digestion decreases
- Decreased ability to produce or absorb certain vitamins
- Poor dentition
- Over/underweight
Which vitamins may geriatric horses struggle to manufacture or absorb?
- B vitamins
- Vitamin C
What factors can lead to decreased feed intake in geriatric horses?
- Less active
- Decreased basal metabolic rate
- Dental disease
- MSK pain - Decreased movement
- Changes in hierarchy - Bullying
- Health changes (e.g., PPID, Asthma, Neoplasia)
What are some considerations for selecting feed for geriatric horses?
- Highly palatable
- Easy to chew & swallow
- Clean & dust free
What are some recommended feeding strategies for geriatric horses?
- Highly digestible pellets or extruded feeds
- High quality fiber to aid digestion
- Chopped hay, hay cubes or pellets
- Soaked feeds or mashes
