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General Breeding Information
The single most prevalent reason for reduced fertility today is lack of cleanliness or sanitation.
by Dickson D. Varner, DVM, MS, Diplomate ACT
Charles C. Love, DVM, Ph.D., Diplomate ACT
Terry L. Blanchard, DVM, MS, Diplomate ACT
Steven P. Brinsko, DVM, MS, Diplomate ACT
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University
Although the upcoming breeding season is 3 months away, a successful year for 2005
begins with preparation of mares and evaluation of stallions right now.
by B. W. Pickett, Ph.D. Professor Emeritus, Colorado State University
Although some of you may feel that the prior breeding season has just ended, it is time to
begin thinking about the upcoming breading season.
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
A uterine biopsy may be collected from a mare by a veterinarian to evaluate the histology or
microscopic anatomy of the uterine lining or endometrium
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
Culture of the uterus to determine if one or more microorganisms are present or if the mare is 'clean'
(i.e. free of organisms) is an important diagnostic test.
Stallions and Stallion Management
A hemacytometer, originally designed to count blood cells, has been used for many years to
count other types of cells. Toward the end of World War II, with the advent of artificial
insemination in cattle, it became painfully obvious that other methods of counting spermatozoa
had to be developed, because of the length of time it required for an accurate count to be
obtained with the hemacytometer.
When the stallion manager and the mare owner have confidence in one another and a spirit
of cooperation, shipped semen has many fewer disadvantages and a much greater chance
of success.
Extenders by B. W. Pickett, Ph.D. Professor Emeritus, Colorado State University
To quote Dr. R.H. Foote, one of the most noted reproductive physiologists of our era, "Artificial
insemination (AI) was the first great biotechnology applied to improve reproduction and genetics of
farm animals."
The birth of the first foal conceived using frozen semen occurred almost 50 years ago. Use of frozen semen was
approved by the AQHA in 2001 and in 200_ the rule was adjusted/an amendment was passed to allow for the use of
frozen semen from a given stallion even after he has died.
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
Artificial insemination of mares with cooled-transported semen has become a routine procedure in the equine
breeding industry. The ability to cool semen makes it feasible to ship semen from one location to another...
Mares and Mare Management
Are You Ready? by E.L. Squires, M.S., Ph.D., hon, ACT, Colorado State University
Dr. Squires outlines a strategy for assuring that mares are ready for the next breeding
season, with considerations for different categories of mares.
by Dickson D. Varner, DVM, MS, Diplomate ACT
Charles C. Love, DVM, Ph.D., Diplomate ACT
Terry L. Blanchard, DVM, MS, Diplomate ACT
Steven P. Brinsko, DVM, MS, Diplomate ACT
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University
Many advances have been made in assisted reproduction for horses in recent years,
and several breed registries in the United States have adopted many of these newly-found
techniques.
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
Mares can continue to produce foals well into their late teens or early to mid 20's. However, mare
owners should realize that the prognosis for fertility of an older mare decreases each year.
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
Cytologic evaluation of the uterus involves the collection and interpretation of cells lining the uterus
(endometrium) and within the uterine lumen. Cytology is used in conjunction with culture and biopsy
in the diagnosis of endometritis
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Economic pressures of the equine breeding industry result in a demand for accurate early pregnancy diagnosis. Some
horse owners presume that a mare that fails to come back into heat within 3 weeks after breeding is pregnant. That is
not necessarily true. Up to 10 % of bred mares that fail to return to heat are not pregnant. Reasons for a nonpregnant
mare not coming back into heat include persistence of the corpus luteum (pseudopregnancy), seasonal effects on
ovarian function, and some ovarian disorders. The most reliable test for pregnancy is ultrasonography. Pregnancy tests
based on hormone levels in blood or urine are generally used only when palpation and ultrasonography per rectum is
not possible.
By Patrick M. McCue, DVM, PhD,
Diplomate American College of Theriogenologists
A vaginal speculum examination is a routine component of a mare reproductive evaluation. The goals
of a speculum examination are to evaluate anatomic characteristics of the cervix relative to stage of
the estrous cycle and to detect abnormal conditions of the vagina and cervix
Foals and Foaling
Retention of the placenta is one of the most common problems of the mare in the early postpartum period. A
placenta is considered to be retained if it has not passed within 3 hours after foaling. The incidence increases
following abortion, dystocia, obstetrical manipulations, cesarean surgery, induction of labor, placental
infections, fescue toxicity and other factors.
Foal Diarrhea b y Patrick M. McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
A majority of foals will exhibit diarrhea at some time within the first 2 months of life. In most cases, the
diarrhea is mild, transient, not contagious to other foals and not life threatening. However, in some
instances, diarrhea can be contagious, severe and possibly even fatal.
Foal Rejection by Patrick M. McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Rejection of a foal by its dam can take several forms. The mare may avoid the foal, prevent the foal
from nursing, or may become aggressive toward the foal. Mares in the latter category may assume
a threatening posture, pin their ears back when the foal approaches, charge or chase the foal,
squeal at the foal, or in more serious cases, may kick at or bite the foal. Mares have, on rare
occasions, seriously injured or killed their foals in the first few days after giving birth.
Foaling Fundamentals by Patrick M. McCue, DVM, Ph.D., Diplomat American College of Theriogenologists
Patrick M. McCue presents an informative array of facts and tips that will be of interest to
beginning and experienced equine breeders alike.
By Patrick M. McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Newborn foals enter the world without antibody protection. Foals are entirely dependent on
antibodies absorbed following ingestion of mare's colostrum in the first few hours of life for
protection against infectious diseases.
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Colostrum is the thick, sticky yellow fluid produced by the mammary gland of the mare
during the last few weeks of pregnancy. It is comprised of carbohydrates, fats, proteins
and electrolytes. Colostrum is rich in antibodies or immunoglobulins that are critically
important for immune protection of the newborn foal.
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Meconium is comprised of digested amnionic fluid, gastrointestinal secretions, bile, and cellular
debris that accumulate in the intestinal tract of the late-term fetus.1 It is usually dark greenish
brown or black in color, firm pellets to pasty in consistency and is generally passed within the
first 3 to 4 hours after birth.
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
An owner or farm manager generally does not know in advance which foal will need supplemental
colostrum. An on-site supply of frozen colostrum can be critical for the health of a valuable neonate.
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
The placenta is the connection between the developing fetus and the mare and provides the means for obtaining
nutrition and for gas exchange. Examination of the placenta can offer valuable insight into the health of the newborn
foal. Consequently, it is recommended that owners, farm managers or foaling attendants perform an evaluation of
each
placenta.
by Patrick McCue, DVM, Ph.D., Diplomate American College of Theriogenologists
Neonatal isoerythrolysis (NI) or Jaundice Foal Syndrome is an uncommon but potentially life-threatening condition of
newborn foals. It has been estimated to occur in 1-2 % of equine births. The condition occurs when a foal ingests
colostrum containing antibodies directed against its red blood cells (RBC’s). Destruction of RBC’s leads to release of
a pigment called bilirubin that may cause the gums, white parts of the eye and feces to become yellow or jaundiced.
