Exam 2 Flashcards
Hitch ball
- the steel, ball shaped piece over which the trailer coupler latches
- diameters are 1 7/8 inch, 2 inch, 2 5/16 inch, 3 inch
Bumper hitch
- some trucks and SUVs have provisions on their rear bumpers for attaching a hitch ball for towing
- only good for light duty applications
Bolt-on hitch
- a permanent hitch ball and bracket that are welded or bolted directly to the tow vehicle
- can be a fixed tongue hitch, which includes the ball and platform or a receiver style with a removable draw bar
Class I hitch
- trailer hitch with a capacity up to 2000 pounds gross trailer weight, with up to 200 pounds of tongue weight
Class II hitch
- trailer hitch with a capacity up to 3500 pounds gross trailer weight, with 300 to 350 pounds of tongue weight
Class III hitch
- trailer hitch with a capacity up to 5000 pounds gross trailer weight, with 500 pounds of tongue weight
Class IV hitch
- trailer hitch with a capacity up to 10,000 pounds gross trailer weight, with 1000-2000 pounds of tongue weight
Class V hitch
- fifth wheel or gooseneck trailer hitch
Coupler
- the forward most part of the trailer tongue that drops over the hitch ball and latches
Fifth wheel hitch
- a class V hitch that mounts in the bed of a pickup truck.
- much smaller, but designed similar to those used on tractor trailers
Gooseneck
- a class V hitch that mounts on the bed of a pickup to engage a coupler on a trailer.
- ball sizes can be 2 5/16 inch or 3 inch
Gross combined vehicle weight rating (GCVWR)
- total combined weight of truck and trailer including all passengers, fuel, fluids and cargo
Gross trailer weight rating (GTWR)
- the manufacturer-specified recommended maximum weight of a trailer when fully loaded
Gross vehicle weight rating (GVWR)
- the manufacturer-specified recommended maximum weight of a vehicle when fully loaded
Safety chains
- these chains attach to the eyelets adjacent to the receiver
- they keep the trailer connected should the coupler come unhooked from the hitch ball
Sway control
- a system that uses a shock absorber to resist side to side swaying movement of a trailer tongue sometimes caused by passing vehicles or cross winds
Surge brake system
- self contained system used on trailers
- have a master cylinder in the trailer coupler
- when you apply the brakes in the tow vehicle, the initial slowing compresses the piston inside the master cylinder to apply braking force at the trailer wheels
Tongue weight
- the downward weight applied by the towable equipment on the hitch ball
- tongue weight should be around 7 to 8 percent of GTW and should not be more than 10% of the GTW
Torsion bar
- a type of suspension that uses bars that twist rather than coil or leaf springs
- weight distributing hitch A receiver style hitch system that includes additional equipment such as spring bars that work to distribute trailer tongue loads to the trailer axles and to the front axle of the tow vehicle
Trailer maintenance
1) before every trip
1) trailer lights and turn signals
2) trailer brakes
3) trailer hitch - is it stable?
4) trailer safety cables
5) spare trailer and truck tires and tools to change a tire, including a jack
6) trailer floorboards
7) wasp nets and other insects
Trailer maintenance
2) every 3-4 months
1) tires (tread,inflation,dry rot) including spare
2) jacks
3) floorboards
4) lights
5) hitch welds, safety chain welds, snaps
6) wheel chocks
7) grease hitch ball as needed
Trailer maintenance
3) yearly maintenance
1) inspection of frame
2) inspection of wiring
3) grease all hinges, springs
4) bearings checked and repacked
5) inspection of brakes and emergency breakaway cable, pin and control box
Loading and Unloading
- SAFETY IS THE KEY FACTOR
1) horse should be trained to load before planning a trip
2) handler should always have an escape route
3) horses should not be tied to the trailer while horses are loading and unloading
4) door should be held open or opened wide
5) horse should be led straight towards the trailer
And handler should walk in first
6) encouragement can be provided with rope or lunge whip if needed
7) once loaded handler can exit and door should be secured after last horse is loaded
8) unloading depends on trailer either horse will back out or can have space to turn and lead the horse out
9) important to be clear of the horse before he gets off the trailer
Traveling with horses
- variables to consider such as length of trip, out of state, more than one horse and if with mare and foal
1) plan to have all traveling paperwork in order before leaving - needs a current minimum of 12 month coggins test (tested negative for equine infectious anemia)
2) consider the stress on the horse - ensuring proper ventilation (travel at night when temp is cooler if in summer)
- have hay available for reassurance (make sure hay bag is hung where horse can’t get foot caught)
- if horse is a nervous traveler bringing a second well-seasoned horse may help calm or hanging a mirror can calm a nervous herd bound horse
3) how long to travel with a horse before stopping - approximately every 400 miles or 6 hours
- take time for horse to stand on trailer without having to balance bc not moving
- offer horse water at each stop
- try to keep horse on trailer until reach destination
- every 10-12 hours horse needs a longer break from balancing (don’t need to unload but needs to stand quietly on trailer)
- if you do unload recommended to find a layover barn with a stall or small paddock for horse
4) double check everything before you leave again - check hitch, all doors, windows and make sure all equipment is secure
- do not travel with drop down windows open unless face guard or screen is there
Estrous
- entire cycle
- 21 days
- 23 days for ponies
2 phases
1) estrus phase
2) Diestrus phase
Estrus
- in “heat” -> when mare is receptive to stallion for breeding
- concludes with ovulation
- 5 to 7 days long
Diestrus
- period between estrus phases
- mare is not receptive to stallion (out of heat)
- 12 to 16 days long
Sub stages
1) luteal phase
- 5 days after ovulation the CL is fully functional and secreting progesterone
- part of estrous cycle when mare is under influence of corpus luteum (secreting progesterone)
- this hormone is needed to maintain pregnancy
2) proestrus
- around day 13 CL regresses
- period post corpus luteum regression and
pre-estrus
- brief period of time where not thinking pregnant, but also not ready for fertilization
Seasonally polyestrous
- multiple estrous periods for a portion of the year and none at other times
- undergoes regular estrus cycles during a portion of time (late spring, summer and early fall) and none at others (winters -> prevents fooling in bad weather)
Anestrus
- complete absence of estrus cycle
- winter periods for the most part bc don’t wanna have a foal in the middle of winter
- no estrus cycle means horse is DORMANT
- in south: anestrus starts around Oct 15-Nov30 and will become estrus again around Feb 1
- period is longer in northern climates
Transitional Phase
- between estrous cycle and anestrus cycle
- either early or late in the breeding season
Ovaries
- the primary sex organ of the mare
- large and kidney shaped, 7-8 cm
- more than 60,000 oocyte(cell that can become ovum-> egg) present at birth
- 10 oocytes used per cycle - 80% of ovulations occur between 4-8am (overnight)
- mare can ovulate with progesterone present
- will cause cycle irregularity
Follicles
- dominant and secondary
- grow 3-5 mm per day (large)
- ovulation size is 45-60 mm
- mare will develop follicles during the estrous cycle
Ovulation
1) when the follicle “implodes” and oocyte passes through ovulation fossa to oviduct
2) once the dominant follicle ruptures it becomes the corpus hemorrhagicum (CH)
- it appears as the black center in a corpus luteum (CL)
3) Becomes corpus luteum which is around 79% of the diameter of the follicle
4) ovulation usually occurs one day before the end of estrus cycle (34%) or the last day of estrus cycle (35%)
- egg is only viable for 12 hours after ovulation
- do not start breeding until we know follicle has reached a critical size
Estrogen
- secreted from follicle
- is responsible for estrus (in heat) behavior
Progesterone
- secreted by the CL that is formed after the mare has ovulated
- prevents estrus cycle behavior -> if a riding horse and don’t want to breed the mare giving this will prevent heat/crabby behavior
- can also help with keeping a pregnancy if mare is not forming accessory CL
Luteinizing Hormone (LH)
- responsible for ovulation
- controls and maintains development of CL
- secreted from anterior pituitary
- use when breeding to ensure timed ovulation it regulates cycle
Follicle stimulating hormone (FSH)
- responsible for follicular waves and dominant follicle development
- helps follicle grow larger
2 Waves: smaller wave and then a larger wave closer to estrus cycle to help follicle grow
Prostaglandin F2a
- responsible for lysing CL (destroys it)
- immediate drop in levels of progesterone which permits mare to begin showing estrus behavior (short cycle the mare-> lutalyse)
- uterus will release this from the uterine lining if can’t detect pregnancy
- occurs approximately day 17-19 of estrus only
- will save time and money bc accelerates estrous cycle to either get mare pregnant faster or terminate the pregnancy
hCG
- times ovulation in mares in estrus cycle
- mimics LH and causes ovulation (human drug that horses are responsive to)
- can only use 2-3 times per estrous cycle because horse will build antibodies and become immune
Deslorelin
- does the same thing as hCG, but won’t lead to build up of antibodies
- more expensive and is a pharmaceutical compounded drug
Transitional Phase
- late winter/early spring; late summer/early fall
- 60 to 90 days in spring -> cycling by April 7 +- 1 week
- negative feedback on production of melatonin
- sufficient FSH, insufficient LH -> no ovulation
Rule of Thumb: 4 consecutive days estrus followed by 8 consecutive days of diestrus, the first day of next estrus considered first day of breeding season
- estrus indicates to begin teasing
- most mares are fully cycling/breed able by first week of April
Phototropic Stimulation
- use of artificial lighting
- induce earlier regular estrus
- same length of transitional phase, but happens earlier in the year
- start 2-3 months prior to desired first breeding date
- requires minimum of one 100 watt bulb in 12x12 stall
- requires minimum of 14-16 hrs/day
- 60 day stimulus required
- extreme cold weather may override
- used to try to trick mare into beginning estrous cycle early but can also be used to keep summer coat on riding horses in the winter
Cessation (end) of light
- return to transitional or anestrus phase
- 3 day cessation
Stallion fertility
- Daily Sperm production -> 7 day collection, then you average the number collected
- 3 to 6 billion sperm cells per day are produced and it takes 57 days to mature
The number of mares a stallion can breed with depends on
1) testicular size -> 80 mm for breeding soundness exam
2) volume of semen -> sperm and secondary fluid
3) number of sperm cells
4) motility -> progressively motile (swimming) KEY
5) morphology (semen shaped correctly)
- primary problems occur in development (can’t help)
- secondary happens during semen processing -> bad management
- abnormalities -> double tails, bent tails (secondary), disconnected heads from tails, cold shock (huddled together)
Morphology anomalies (in sperm)
1) primary anomalies-> genetic errors
2) secondary anomalies-> semen handling, human error
Stallion Management
1) exercise -> physical and psychological health
- worry about mental health is if stallion only exercises on hot walker will become “Tarzan”
2) anabolic steroids negative feedback
- reduced reproductive efficiency
3) stallion handling
- breeding should be pleasing, excitement okay as long as safety is not compromised
- handler safety most important
- let them have enough libido, act like a “stallion” but still mannerly with handlers
- consistency aids libido -> direction to breeding shed, use certain halter, handling different for work and for breeding. Mannerly for work and libido for breeding