EQUUS

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2003
9152
8171
51120
160980
11050
14298
37000
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Color Breeds

• Palomino

• Buckskin

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Equine Coat Color Genetics

• Price differences for horses of various colors
  have created a demand for knowledge about color
  genetics
• Coat color is determined by a combination of
  several genes

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Gene W

• Unable to form pigment in skin and hair
• Overrides all other color genes
• WW lethal, dies in early pregnancy
• Ww pink skin, white hair, brown or blue eyes
  (albino)
• ww allows expression of other color genes

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Gene G

• Causes horses to be gray
• Progressive graying, any color at birth
• Original skin and eye pigment maintained
• GG becomes gray
• Gg same as GG
• gg no graying

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Gene E

• Controls black hair
• EE ability to form black skin and hair
• Ee same as EE
• ee red hair (chestnut, sorrel), black skin

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Gene A

• Controls distribution of black hair
• Affects only EE and Ee
• AA black at points (mane, tail, legs)
• Aa same as AA
• aa black over entire body

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Gene C

• Cream gene
• Causes pigment dilution
• Incomplete dominance
• CC red and black diluted to pale cream
• Cc red diluted to yellow
• cc full pigment according to other genes

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Equine Coat Color Genetics
White Ww -- -- -- --
Gray GG/Gg -- -- -- --
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Bay EE/Ee, AA/Aa, cc, ww, gg
Black EE/Ee, aa, cc, ww, gg
Red (Sorrel) ee, aa, cc, ww, gg
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Buckskin EE/Ee, AA/Aa, Cc, ww, gg
Palomino ee, AA/Aa/aa, Cc, ww, gg
Cremello CC -- -- -- --
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Equine Coat Color Genetics

• White X White? Ww -- -- -- --
• 25 dead, 50 White, 25 any color
• Red X Red? ee, aa, cc, ww, gg
• 100 Red
• Buckskin X Buckskin? EE/Ee, AA/Aa, Cc, ww, gg
• Bay, Black, Red, Buckskin, Palomino, Cremello

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Equine Coat Color Genetics

• http//www.vgl.ucdavis.edu/7Elvmillon/coatcolor/c
  oatclr3.html

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• 5) Dun/Not Dun (D and d)
• D Dilutes pigment to dun variation (Affects
  black and red pigment).
• dd Doesnt allow dilution.
• In horses carrying the dominant D allele
• Red is diluted to pinkish-red with dark points
  producing a red dun.

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• Bay is diluted to yellow with black points
  producing a buckskin dun.
• Black is diluted to mouse-gray with black points
  producing a grulla.

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• 6) Roan/Not Roan (RN and rn)
• RN Produces a roan.
• rn Doesnt allow roaning.
• Horses with a mixture of white and dark hairs on
  the body and dark heads, manes and tails.
• Red Roan (ee, RN) Blue Roan (E, aa, RN)

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Reproduction

• Horses are a model of reproductive inefficiency
  
• Puberty
• Estrus Detection
• Mating
• Breeding Season
• Foaling

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Puberty

• Fillies _at_ 12-15months
• breed at 2yrs
• Colts ready for breeding at 2yrs
• No known effect of subjecting fillies to stallions

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Estrus Detection

• Relaxation of external genitalia
• Frequent urination
• Watery mucous discharge
• receptiveness to stallion
• teasing

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Estrous Cycle

• Cycles are 21-23 days long
• Estrus is 3-7 days long
• Ovulation can occur anywhere from one day before
  to one day after the end of estrus
• No way of predicting the length of estrus

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Estrus Detection

• Ovulation nearing
• Palpation and ultrasound are the most valuable
  tools for detection
• Both are used to check size of follicle
• Avg 4.5cm follicle single ovulation

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Breeding

• Natural and A.I. usually done every other day
  once palpable follicle is detected or 3rd day
• Best if sperm deposited within 12 hrs of
  ovulation.

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Breeding

• Would this be a problem in the wild??
• Mate every day the mare is in estrus
• One source of created inefficiency

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Figure 2115  Mare seasonality. (Source Slusher
et al., 1998, p. 3974.1. Used with permission.)
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Breeding Season

• Cycles in mares controlled by daylength
• Breeding season lasts from Early Spring until
  Late Summer
• How long is gestation?
• 336 days
• When do mares recycle after foaling?

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Postpartum Anestrus

• Foal Heat when?
• 7-10 days after foaling
• Can they get pregnant?
• What are benefits/risks
• Benefits pregnant for next year
• Risks early embryonic mortality
• Later term abortions
• Gamble breed here or wait to later heat
• Risks of waiting?
• May move into seasonal anestrus wait till next
  year

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Artificial Lighting

• Use to extend breeding season
• Can be done with a regular 100 watt bulb
• 16 hrs
• 60-80 days prior to normal cycle

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Foaling

• Pre-foaling measures
• Watch teats for waxing
• sinking in of haunches relaxin
• safe, quiet, place to foal
• mares may become colicky

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Stage 1

• begins with the onset of contractions
• lasts 1-2 hours
• foal moving into position
• ends when the water breaks

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Stage 2

• actual expulsion of the foal
• 30 minutes or less
• normal foal presentation
• mare may stand up or lie
• down

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Stage 3

• afterbirth is expelled
• 1-3 hours
• over 3 hours could lead to infection

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Health Management

• Common diseases
• equine encephalitis (aka. sleeping sickness)
• viral annual vaccination
• influenza
• viral show horses
• Strangles (distemper)
• bacterial highly contagious vaccinate rarely
  fatal
• equine infectious anemia (aka. swamp fever)
• no treatment Coggins test required for
  show/sale
• If positive, 2 choices in OH destroy horse or
  maintain 150 yards from other horses freeze
  branded A

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West Nile Virus

• First case reported in the Western Hemisphere in
  1999
• Vector Mosquitos
• Effects mainly birds, horses and humans
• Encephalitis

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Rhinopneumonitis

• Virus, can vaccinate
• Causes abortions in pregnant mares
• Neurological strain occurred at University of
  Findley
• Horses develop symptoms quickly cannot hold
  themselves up--are placed in slings
• 10 of the Findley horses died

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Horses in the USA

• Horse Numbers in the US
• 1920s
• 26 million Horses
• Used for Transportation and Farming
• 1960s
• 3 million horses
• Present Day
• 6.9 million Horses-Mostly used for Pleasure,
  Showing and Racing

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Impact of the Horse Industry

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The Ohio Horse Industry

• Economic Impact-2.8 billion
• Total Horses 192,000
• Racing 40,000 major race close to Columbus?
• Showing 66,000
• Recreational 68,000
• Other 17,000

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The Ohio Horse Industry

• American Quarter Horse Industry
• 52,755 Quarter Horses
• 62 shows/year with an average of 655 entries
• Two Top 5 Special Event Shows
• All-American Quarter Horse Congress
• Top AQHA Show in total entries