Equine breeding management Flashcards
Horses are seasonal long day breeders and seasonally polyoestrous what does this mean
Seasonal ‘long day’ (spring/summer/early autumn) breeders
Seasonally polyoestrous (21 days between each ovulation)
2week dioestrus, 1week oestrus
When to breed a horse
First Ovulation April ongoing to September
Outline Spring transition manipulation (breed during spring transition)
Photostimulation Length = 14.5 h (14 – 16 h)
Artificial light (8-10weeks prior to when breeding commences)
Progesterone intravaginal devices
On average what month would you expect a sexually mature mare to have had her first ovulation of the breeding season
April
What is the function of teasing
Mare is exposed to a stallion and behaviour is assessed for evidence of receptivity
Differentiates oestrus from dioestrus
LACK OF PROGESTERONE that drives mating behaviour
Signs of Oestrus during teasing
Quiet and calm & ears forward
Tail up, urinating and winking
Can you use palpatation to determine state of mare’s oestrous cycle
Can assess cervical and uterine tone
Dioestrus: high PROGESTERONE = uterine tone prominent and cervix is closed (cigar like)
Oestrus: high Oestrogen & low Progesterone = soft uterine tone and relaxed open cervix
Can’t palpate CL
5 ways to determine mare’s state in her heat cycle
Teasing
Rectal palpation
Ultrasound
Endocrinology
Vaginal speculum
Describe oedema differences in different stages in heat cycle
Oestrus - oedema increases each day until maximum and then starts to reduce prior to or at time of ovulation
Dioestrus – no oedema
Anoestrus – no oedema
Phyometra
Air in uterus- No good
Outline using endocrinology to determine stage in mare’s heat cycle
Serum Progesterone conc >1ng/ml dioestrus
<1ng/ml in oestrus or anoestrus
Progesterone increases or decreases during horse’s oestrous
DECREASES
Which of the following methods would accurately confirm that a mare has recently ovulated?
Indifferent teasing behaviour
Vaginal speculum exam showing a raised cervix
Transrectal palpation of the ovaries
Ultrasound visulising a Corpus Haemorrhagicum on her ovary
Breeding records indicating 3 weeks from previous ovulation
Ultrasound visualizing a Corpus Haemorrhagicum on her ovary.
Main idea of oestrous cycle control in the mare
Shortening of CL lifepsan
Drug used to shorten CL lifespan to control oestrous cycle
Prostaglandin
Dinoprost tromethamine (Lutalyse®)
Cloprostenol (Estrumate®)
Two drugs used to induce ovulation in the mare
Human chorionic gonadotropin (hCG (Chorulon®)
Biorelease Deslorelin
Outline Oestrus suppression in mare
Determine if ovaries /ovarian hormones are the cause of undesirable behavior
History, physical exam and reproductive exam to check stage of the oestrous cycle and determine pathology
Keep a behaviour diary and track undesirable behaviour
Treatment trial with oral progestin (30days)
Name of drug used to suppress oestrous in mare
Oral progestin- Altrenogest
4 methods to suppress oestrous in mare
Progestin treatments
Intrauterine marble
Ovariectomy
Equity®Oestrus Control Vaccine
The use of the GnRH analogue Deslorelin is used most in the mare for
Oestrous suppression
Vernal transition manipulation
Ovulation induction
Oestrus synchronization
Shortening of CL lifespan
Ovulation induction
How does Equity® Oestrus Control Vaccine control oestrous
Administer the vaccine to produce antibodies against GnRH, reducing LH and FSH release.
How does Intrauterine Marble control oestrous
Presence of the marble mimics the presence of an embryo, which can prolong the luteal phase and prevent the mare from returning to estrus.
How does Progestin Treatments control oestrous
The synthetic progestins maintain elevated levels of progesterone in the mare’s system. High progesterone levels inhibit the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which in turn prevents the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. Without LH and FSH, the follicles in the ovaries do not mature and ovulate, thus preventing the mare from coming into estrus (heat).
What is handmating
When a stallion and mare are handled in such a way that they are both restrained, and the act of breeding is orchestrated in a controlled environment.
How often can mare be handmated
Mares can be hand mated every other day when in oestrus or by a single breeding during oestrus.
Advantages of mare handmating
Breeding’s can be scheduled and the mare can be examined prior to and after breeding to confirm ovulation occurred and no reproductive issues are present.
disadvantages of mare handmating
Increased time required for teasing mares, more personnel required for the breeding process and risk of injury to personnel in breeding shed.
Advantages of AI
Semen Evaluation: Quality can be assessed after collection and before insemination.
Multiple Doses: One ejaculate can be processed into multiple doses for inseminating mares.
Reduced Contamination: Hygiene measures and semen extenders with antibiotics minimize the introduction of organisms into the uterus.
Injury Prevention: Reduces risk of injury to mare, stallion, and personnel compared to hand or paddock mating.
Genetic Diversity: Chilled and frozen semen provide access to a broader selection of stallions and a larger genetic pool.
Sperm viability once thawed
12-24 h
How many hours after can you see oocyte during after ovulation
6 – 12 h post-OV
Check every 6 to 8 h
How many days after ovulation can you see pregnancy in mare and diagnosis
14-15 days post-ovulation
Palpation per rectum
U/S
Which of the following breeding management practices is most intensive with regards to the number of mare examinations required per cycle?
Frozen semen single dose AI
Chilled semen AI
Natural paddock serve mating
Frozen fixed time double dose AI
Frozen semen single dose AI
