Flashcards in 6a Life Cycle Nutrition of Horses 2 Deck (29):
What 4 parts make up the heat increment?
1. heat of product formation
2. health of digestion and absorption
3. heat of waste formation and excretion
4. heat of fermentation
How long is the estrus cycle of the horse?
What is the estrus cycle influenced by?
What is the season for seasonal polyestrous?
- inherited trait
- better to be foaling in spring when there is adequate pasture
What is a footcandle and how much is needed to stimulate cycling?
- measure of light intensity
- the illuminance cast on a surface by a one candela source one foot away
- 10 foot candles 16h a day
Describe the estrous cycle of the broodmare.
- pineal gland stimulated by light and reduced melatonin production
- increases in GRH
- LSH and FH stimulate follicle to develop
- at peak estrogen, follicle ovulates
- corpus luteum produces progesterone
- if no pregnancy detected, PF2a stimulates lysis of CL
Where are 6 body sites to determine fat deposition?
- crease down loin
- along withers
- along neck
- behind shoulder
- 335-345 days
- winter conception has longer gestation period due to photoperiod in last 3 months
- can shorten gestation by 11d with 16h light
- BCS very important (>5 BCS)
- protein and energy requirements not completely determined
- deficiencies can be partly offset (mare can adjust to situations)
- ideal = gain12-15% above normal BW
What are the effects of an optimum BCS?
- increased fertility
- increased milk yield
- increased health
- will have shorter follicular phase, increased cycles and shorter winter inserts
- low BCS leads to longer anestrus due to decreased hormone levels
What 5 things do energy requirements during pregnancy go towards?
1. maintenance of dam
2. deposition of fetal and placental tissue
3. hypertrophy of the uterus
4. mammary development
5. maintenance of accumulated tissues
When does tissue accretion occur during gestation?
- fetal and non fetal accretion greatly increases after d150
- most fetal tissues accumulated in last 60 days od gestation
- non fetal tissue is very metabolically active
What are the energy requirements during pregnancy?
- met by DEm for first 5 months
- months 5-8 increase by 11%
- month 9 increase by 15%
- month 10 increase by 21%
- month 11 increase by 28%
What happens with mares who have BCS <5?
1. delayed estrous
2. reduced conception
3. embryonic death
What other factors may affect energy requirements during gestation?
- food availability
- nutrient quality
Protein requirements during pregnancy.
- too little can caught weight loss or early fetal loss
- fetal weight gain related to gestational age
- conception to 4th month: average CP requirement
- month 5 until parturition: maintenance + fetal gain
- lysine requirement 4.3% of CP requirement
What are some other mineral requirements for pregnancy?
- increased requirements of Ca, P, Mg and K during late gestation because non fetal tissue accretion
- increase vitamin A and E to 2x maintenance
Feeding during parturition
- 24h before birth, feed intake should be reduced (good quality hay, low quality cereal, bran assists in digestion)
- after parturition, energy and protein needs must be met (first feed be bran mash, then feed with cereal and protein)
- restrict concentrate feeding to 10 days post datum to avoid excess milk secretion and Gi disturbances in foal
- too much milk can cause fermentation in foal gut
How does milk production change after gestation?
- first few days 5-15kg/d
- months 2-3 10-20kg/d
- month 5: 5-10kg/d
What 5 things are milk yield influenced by?
1. feed consumption during late gestation
2. Feed quality
3. water availability
4. nutrient and energy intake
5. breed, nursing frequency, BCS
Describe energy requirements during lactation.
- DE maintenance + DE milk production
- month 1-2: 75% increase
- month 3-4: 62-66% increase
- month 5-6: 50-55% increase
Describe protein requirement during lactation
elevated CP requirement + milk production
- lysine requirement = CP x 4.3% + milk production
Describe calcium requirements for lactation
- demand for Ca
- mares lose bone density during first 3 months of lactation
- Ca requirements decreases as months of lactation pass
Describe P, Mg and K requirements during lactation.
- reduction in requirements as lactation decreases
- encourages weaning
What are some factors that would increase energy requirements of stallions?
- they are breeding!
- extra energy if lots of live cover
- DE requirement depends on breeding frequency
- limited research but recommend 20% higher
What are some physical signs of aging?
- chronically low body condition score
- loss of muscle mass
- sway backed appearance
- gray coat
- dental disease
What are some general considerations of aged horses?
- large metabolic changes in older horses
- dental abnormalities common in older horses (alter physical form to increase digestibility, feed chopped hay, soak hay or hay cubes in water, supplement oil)
Energy requirement of aged horses
- MER lower in aged animals because reduction in lean tissue
- MER relationship to age undefined in horses
Protein requirements in aged horses.
- suggest there is a decline wit aging
- requirements undetermined
- lower CP digestibility in aged vs young horses