Mares, Foals, Stallions and General Health
Baldivis Vet Hospital has a special interest in breeding horses and caring for foals.
Mare
Overview of reproductive physiology
Mares breed in the longer day length of the year. Large breed mares cycle each 21 days while ponies often take 23 days. Mares stay in season 3 to 7 days depending on the stage of their season. Mares generally ovulate when they have a 35 to 45mm follicle.
Veterinarians use a transrectal ultrasound to determine the best time to breed the mare and this procedure is often called a follicle test. Factors such as follicle size, follicle softness, follicle shape and endometrial oedema indicate the proximity to ovulation.
A typical breeding cycle breeding using natural cover or cooled semen consists of:
- Follicle tests to determine where the mare is in her oestrus cycle and how long to ovulation. Generally mares are examined each second day then daily as ovulation approaches
- An endometrial swab to culture for bacteria
- Ovuplant or chorulon are often given to induce ovulation within an average of 41 or 36 hours respectively
- Breeding with stallion or insemination with cooled semen
- Post breeding examination to detect ovulation(s) and to determine whether the uterus is normal
- Post breeding treatments may be required if the uterus is inflamed or contains excessive fluid
- Problem breeders may require various treatments to help them establish pregnancy
- Pregnancy diagnosis needs to be carried out 14 or 15 days from ovulation. It is important to examine mares prior to day 16 so twin pregnancies can be effectively managed
- Follow up pregnancy tests at 25 and 45 days
- Problem breeders may require a uterine biopsy and another endometrial swab for bacterial culture
Breeding mares with frozen semen
Generally the breeding cycle is similar to breeding with cooled semen except mares need to be bred at ovulation. Mares for frozen semen are follicle tested at regular intervals and ideally are bred within 2 hours of ovulation. Often frozen semen causes significant post covering inflammation and mares usually require a post breeding lavage.
Foal
Many foals will stand within 30 minutes of birth and suckle within 60 minutes. Generally foals are considered abnormal if they do not stand within 2 hours of birth and/or don’t suckle within 2 hours of birth.
The first milk from the mare is called colostrum and foals need to absorb the antibiodies (IgG) from the colostrums. The IgG from the colostrum enables the foal's immune system to function properly. We recommend that all foals are IgG tested at 8 to 12 hours after birth to ensure they have absorbed the IgG in the colostrum. A plasma transfusion is recommended for foals that fail to absorb IgG/colostrum.
Useful Links
Developmental Orthopaedic Disease: Problems of Limbs in Young Horses
http://www.equineortho.colostate.edu/questions/dod.htm
Diagnosis and Treatment of Osteochondritis Dissecans
http://www.equineortho.colostate.edu/questions/ocd.htm
Angular Limb Deformities and Physitis
http://www.equineortho.colostate.edu/questions/angular.htm
Flexural Deformities
http://www.equineortho.colostate.edu/questions/flexural.htm
Common problem with foals
Neonatal septacaemia
Neonatal septacaemia is a widespread blood infection that affects many organ systems. Generally bacteria originate from the foal’s intestine. Foals usually appear normal for 24 hours to 48 hours then rapidly become ill. At Baldivis Vet Hospital we aim to recognise foals at risk of neonatal septicaemia and where possible prevent disease.
Baldivis Vet Hospital has a purpose built hospital and staff present 24/7 treat foals with septicaemia.
Meconium retention
Some foals become constipated on the faecal material present in the rectum at birth. Retained meconium is often cleared by an enema however some cases may require intensive treatment.
Diarrhoea
Many foals develop diarrhoea at 7 days of age and this diarrhoea is often called "foal heat diarrhoea". Diarrhoea is caused by an overgrowth of bacteria in the foal's intestine and this often occurs at the time of the mare’s foal heat. Most diarrhoea’s settle within a few days. However, the intestine of some foals is colonized by pathogenic bacteria such as Salmonella spp and/or Clostridium spp and severe diarrhoea can develop. Foals with severe diarrhoea require hospitalization, intravenous fluid therapy and other treatments.
Bent Legs
Many foals are born with bent limbs and most of these straighten without requiring treatment. Deviations of the fetlocks must be corrected at an early age while those involving the knees can be given a little time to correct naturally. Vets at Baldivis Vet Hospital are practiced at observing foals and determining which foals require early intervention to correct leg deviations.
Other illnesses
Generally any illness in a foal can be potentially serious and our advice is to have any abnormal foal examined.
Stallions
Baldivis Vet Hospital provides semen collection for stallion fertility evaluation, semen preparation for cooled transport and semen freezing. Stallions are semen collected on a dummy or on a jump mare. The mare is brought into season using hormones.
Useful Links
Andrologic Examination of Older Stallions
http://www.vetcontact.com/en/art.php?a=736&t
General Health
Colic
Colic means abdominal pain and it is a common abnormality which requires veterinary treatment.
The signs of colic include:
- Lying down
- Looking at the abdomen
- Not eating as normal
- Stretching out as if to urinate
- Rolling
- Pawing at the ground
- Lying down and getting up
- Lying on their back
Causes of colic are varied and only sand colic is discussed as it is common in our area.
Sand colic - occurs when the horse accumulates sand in the large intestine. Predisposing factors are generally a white sand in the paddock, reduced amount of hay in the diet, heavy grazing on kikuya and/or new shots of grass at the start of the season. Horses often present with colic around the afternoon feed time. Often sand can be heard in the ventral abdomen. Treatment includes drenching with paraffin oil, sometimes Epsom salts and medications relieve pain. More severe sand colic requires hospital treatment and intravenous fluids. Severe cases may require surgery to remove the sand. In some cases the weight of sand in the colon causes the colon to twist and these cases require surgery.
