Title: EQUUS
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2Color Breeds
3Equine 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
4Gene 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
5Gene 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
6Gene E
- Controls black hair
- EE ability to form black skin and hair
- Ee same as EE
- ee red hair (chestnut, sorrel), black skin
7Gene 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
8Gene 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
9Equine Coat Color Genetics
White Ww -- -- -- --
Gray GG/Gg -- -- -- --
10Bay EE/Ee, AA/Aa, cc, ww, gg
Black EE/Ee, aa, cc, ww, gg
Red (Sorrel) ee, aa, cc, ww, gg
11Buckskin EE/Ee, AA/Aa, Cc, ww, gg
Palomino ee, AA/Aa/aa, Cc, ww, gg
Cremello CC -- -- -- --
12Equine 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
13Equine Coat Color Genetics
- http//www.vgl.ucdavis.edu/7Elvmillon/coatcolor/c
oatclr3.html
14- 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.
15- Bay is diluted to yellow with black points
producing a buckskin dun. - Black is diluted to mouse-gray with black points
producing a grulla.
16- 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)
17Reproduction
- Horses are a model of reproductive inefficiency
- Puberty
- Estrus Detection
- Mating
- Breeding Season
- Foaling
18Puberty
- Fillies _at_ 12-15months
- breed at 2yrs
- Colts ready for breeding at 2yrs
- No known effect of subjecting fillies to stallions
19Estrus Detection
- Relaxation of external genitalia
- Frequent urination
- Watery mucous discharge
- receptiveness to stallion
- teasing
20Estrous 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
21Estrus 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
22Breeding
- 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.
23Breeding
- Would this be a problem in the wild??
- Mate every day the mare is in estrus
- One source of created inefficiency
24Figure 2115 Mare seasonality. (Source Slusher
et al., 1998, p. 3974.1. Used with permission.)
25Breeding 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?
26Postpartum 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
27Artificial Lighting
- Use to extend breeding season
- Can be done with a regular 100 watt bulb
- 16 hrs
- 60-80 days prior to normal cycle
28Foaling
- Pre-foaling measures
- Watch teats for waxing
- sinking in of haunches relaxin
- safe, quiet, place to foal
- mares may become colicky
29Stage 1
- begins with the onset of contractions
- lasts 1-2 hours
- foal moving into position
- ends when the water breaks
30Stage 2
- actual expulsion of the foal
- 30 minutes or less
- normal foal presentation
- mare may stand up or lie
- down
31Stage 3
- afterbirth is expelled
- 1-3 hours
- over 3 hours could lead to infection
32Health 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
33West Nile Virus
- First case reported in the Western Hemisphere in
1999 - Vector Mosquitos
- Effects mainly birds, horses and humans
- Encephalitis
34Rhinopneumonitis
- 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
35Horses 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
36Impact of the Horse Industry
37The 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
38The 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