HTBA & HVERF
Course Notes
2011 Stud Middle Management Seminar
Basic Reproduction in the Mare Lecture One DR JOHN CHOPIN BVSc PhD FACVSc Registered Specialist in Equine Reproduction, Resident Veterinarian Coolmore Australia
ANATOMY Summary There are 2 ovaries in the mare (right and left). The ovaries play a critical role in reproduction to produce the oocyte (egg) for fertilisation and the hormones that help reproduction. Ovarian size can depend on activity. Small ovaries are found in anoestrus, whereas maximal size and activity is found during the breeding season. Once the follicle has released the oocyte, it collapses and forms the next important structure of the ovary – the corpus luteum. Corpora lutea (the plural of corpus luteum) form after ovulation and can start with a blood clot. The clot then shrinks and is replaced by yellow luteinised tissue which will undergo luteolysis (destruction of the corpus luteum) and form the corpus albicans. During pregnancy extra corpora lutea can form under the influence of endometrial cups between days 40 to 160. The uterine tube joins the ovary to the uterus and is the site of fertilisation and early embryonic life. The uterus is bipartite with 2 horns and a body. The endometrium has conspicuous folds with a cell cycle related to the stage of the oestrous cycle .
UTERUS
BLADDER
EXTERNAL GENITALIA
OVARY
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The
chemical
structure
for
deslorelin
is
{(6-D-tryptophan-9-(N-ethyl-L-prolinamide)-10-
deglycinamide)}GnRH. The product is a biocompatible pellet, which causes no systemic side effects and minimal local reaction. Deslorelin stimulates the release of luteinising hormone (LH) from the anterior pituitary, thus the administration of a deslorelin pellet induces ovulation within 48 hours in 80 – 96% of mares with a mature follicle. The efficacy of deslorelin inducing ovulation is equal to hCG. There is no evidence of refractoriness with repeated use, although recent work suggests there might be an increase in interovulatory period with repeated use of deslorelin in a small number of mares. The interovulatory period was significantly lengthened when control ovulations (22.0 days) were compared to those after the administration of 3 deslorelin implants at once, or one deslorelin implant administered daily for 3 days (36.8 days). Gonadotrophs were lower in the subsequent dioestrus when deslorelin was used to induce ovulation, with FSH and LH suppressed for at least 14 days after deslorelin administration. Despite early work to suggest that deslorelin does not have any negative side effects, the body of new work suggests a hypothalamic and/or a pituitary suppression in most mares for up to 2 weeks post administration.
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Cycle and Hormonal Revision; Cycle Modifications Lecture Two DR ALLAN GUNN BSc.Agric; BVM&S; MACVSc (horse medicine; reproduction); MRCVS; Diplomate ACT
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Parturition in the Mare Lecture Three Dr, J A ROGER, BVMS, MRCVS,FACVSc Specialist in Equine Reproduction CENTRE FOR EQUINE REPRODUCTION MEDICINE, JERRY’S PLAINS, NSW
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The human pregnancy was illustrated by Leonardo da Vinci in 1489
Some of the first accurate descriptions of the developing human foetus and obstetrics were done by none other than Leonardo da Vinci at the end of the 15 th Century. His excellent illustrations showed the developing foetus in the uterus, and he had some wonderful illustrations of foetal malpresentations at birth. Human dystocia was a disaster and as you will shortly see a caesarian procedure was not a great option for the mother!
Assisted births were not always successful and the history of modern obstetrics is relatively recent •
Between 1786 and 1876 not one woman survived a caesarian in Paris
•
In the 1880’s mortality was 92% in New York
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At the same time mortality was 12.5% for slaves in Louisiana “here it was performed early in labour because there was little concern for the mother”
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In a study mortality was 44% where women did sections on themselves or were gored by bulls -less than half the mortality having a physician operating in late labour!
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By 1930 “maternal mortalities were less than 2% in early labour,10% in late labour, 15% after induction of labour and 27% after failed forceps delivery in the second stage of labour
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Common Diseases in the first three days Lecture Four DR NIAMH COLLINS, Diplomate ECVIM Clovelly Intensive Care Unit, Scone Veterinary Hospital
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Introduction Over the last 20 years there have been large developments in the treatment and management of a sick foal so that the old belief of a “sick foal is a dead foal” is no longer true. Many studies have highlighted that the quick early recognition of the sick foal and subsequent early aggressive treatment is critical to a successful outcome. Recognis ing the “high-risk pregnancy” and being prepared for the birth of a compromised foal is also essential. The following article outlines problems that may indicate the birth of a potentially compromised foal, how to detect an abnormal foal and some of the more common neonatal diseases. Careful monitoring of the pregnant mare is essential to detect any problems which may be occurring with the pregnancy. Any systemic illness the mare has during her pregnancy such as colic, diarrhoea or laminitis may have an impact on the foetus and result in the birth of a weak, compromised foal. Mares showing clinical signs of an abnormal pregnancy may also produce a potentially compromised foal. The most common abnormal clinical signs seen during pregnancy are a purulent vaginal discharge and premature lactation or udder development, which are clinical signs of placentitis. The infection in the placenta can spread and cause an infection in the foetus. The placenta may also be compromised and therefore not provide adequate nutrition and oxygen to the foetus. A mare with a previous history of an abnormal delivery or problem pregnancy should also be monitored closely as she has an increased likelihood of producing another compromised foal. The identification of a potential problem with the pregnancy and the high possibility of a compromised foal being born should alert stud personnel and the veterinarian so there is closer monitoring of parturition and the newborn foal and there is potentially earlier detection of neonatal illness… the key to a successful outcome.
The Normal Foal It is important to know the normal behaviour and parameters of a neonatal foal so the subtle abnormalities of a sick neonatal foal can be detected (Table 1). A normal foal after birth should be immediately active and trying to support its head and sit sternal. The foal should be responsive and touching the foal’s nostrils and ears should evoke a brisk response. The foal should develop a - 73 -
Foal conformation & Uterine tube assessment and PGE deposition in mares Lecture Five Dr ANGUS R ADKINS, BVSc FACVSc Specialist in Equine Surgery Scone Equine Hospital - 86 -
Limb Conformation and Methods of Correction in Foals Introduction This article has been written to provide you with a summary of foal conformation – the anatomy and how growth occurs, causes of conformational faults, the definition of conformational faults, how to assess conformation in foals and the treatment options. The lecture I give will be an interactive presentation to show you the types of conformational faults seen, how to assess these and what methods of treatment are available. Conformation is a commonly evaluated component of any potential athlete. Some believe certain conformational traits can have an effect on a horse’s potential speed and that horses with a certain conformation have a better chance of being sprinters or stayers. These are the traits often evaluated by buyers at yearling sales and thankfully there are differing opinions as to the ideal conformation, thereby allowing the sale of all types of horses. The consideration of body type is beyond the scope of this lecture and I will concentrate on lower limb conformation as this is an area we can potentially manipulate to correct perceived faults. I doubt lower limb conformation can significantly affect a horse’s potential speed, but it can certainly affect a horse’s chance of developing lameness, thereby affecting its speed and performance. Certain conformation traits have been shown statistically to increase a horse’s chance of developing ligament injuries, knee chips and inflammation of fetlocks and knees. Many critics of surgery to correct limb deviations are of the opinion this is being done purely to increase a horse’s saleability. This is one reason, but I have no doubt a horse with good conformation has a better chance of racing earlier in its career, for longer, and with fewer interruptions to its training program. This can significantly impact on the cost of training a horse. Lower limb conformation can certainly be manipulated by non-surgical and surgical means and a thorough understanding of these techniques should be known by all staff on stud farms. These is a “window of opportunity” to allow manipulation of limb conformation, and if this window is lost, permanent conformational faults will result. Manipulation can only be undertaken if a fault is first recognised and brought to the attention of the manager, farrier or veterinarian. As such, the principles of anatomy and growth, causes of faulty conformation and the recognition conformation faults must first be known. This will allow a better understanding of the techniques - 87 -
Foal farriery & notes on laminitis assessment and treatment Lecture Six MICHAEL (‘SPOOK’) NEVILLE , Farrier
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Foal Limb Correction There are 2 natural causes which make it important for us to monitor foal limbs in the early stages of their young development. Foals are born with a very soft, pliable hoof, not much harder than jelly! This hoof hardens in time relative to conditions. Foals that are stabled or in irrigated yards, take longer for the hoof to harden than those in harder yards or paddocks.This hoof is generally long and is vulnerable to uneven wear or breaking away as it hardens, due to conditions and conformation. Foals are also born with very little muscle tone. They are very flexible and susceptible to change at an early age. This muscle tone develops rapidly, so it is very important to aim his correction along with muscle development. It is easier to correct a foal limb while the muscles and joints are developing, especially when correcting upright or flaccid foals. Therefore it is important to look at foals at: 
7-10 days of age, to ensure that the soft hoof is worn evenly, to ensure minimal pressure on growth plates. As well as being able to grade the foals limbs so that the grades can be compared at the next trim.
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It is then important to have a re examine date that is adhered to. In most cases, 10-14 days is sufficient, but worse cases in 7-10 days
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a second assessment at 20-24 days of age, is important to ensure the grade of the limb is correcting not worsening, as the best window for lower limb correction, especiall y using periostal elevations is at 3-5 weeks with most normal developing foals.
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