Equine Matters Spring 2019

18 Equine Matters Spring 2019 Some mares also experience pain at, or around the time of ovulation and may show colic symptoms. Veterinary internal examination may elicit a severe pain reaction on ovary palpation on the side of follicular development. These mares may have repeat colic episodes during their oestrus cycle. If there is any infection within the mare’s reproductive tract, such as infection in the uterus (endometritis), the mare will often short cycle, coming into oestrus more frequently than the normal 21 day interval. The inflammation of the uterus lining may stimulate hormones to mark the mare’s return to season more quickly. If a mare is short cycling, then veterinary examination of the uterus would be recommended. This may consist of ultrasound, swabs and biopsy of the uterine tissue itself. Treatment of the endometritis should return the mare to a more regular cycling pattern. Although moody behaviour is common in mares under the influence of hormones (such as oestrogen), it is essential to rule out other non-hormonal causes of pain-type behaviour before embarking on treatment to suppress oestrus. Common causes of such behaviour include back or saddle pain, gastric ulcers, low-grade lameness or dental pain. A thorough veterinary examination of your mare is essential to establish the cause of such behaviour and to plan the optimal treatment or management. Treatment options for the moody mare: 1. Hormone therapy Use of progestogen in the mare stops the mare’s cycles (acting like the human pill). This can be administered daily in feed (Regumate) or injected weekly. 3. Vaccination Although not licensed in the UK, a hormone (GnRH) vaccine has been shown to suppress mares’ oestrus activity. Some injection site reactions have been reported. A similar vaccine is available in Australia and is licensed there for horses. It also carries much less risk of side effects although importation is very costly. Vaccines of this type are not suitable for mares which may be considered for breeding in the future. 6. Feed Supplementation and Calmers There are many supplements on the market for the treatment of moody mares. Although none of these have been shown to suppress oestrus or affect hormone levels, there is anecdotal evidence these can help some mares. 5. Surgery A permanent solution to hormone related moody mare behaviour is to surgically remove both ovaries (ovariectomy). This surgery is carried out under standing sedation and local anaesthesia, using laparoscopy (key-hole surgery) via the mare’s flanks. 2. Uterus Implantation Implantation of either a marble or plant oil (such as peanut oil) into the uterus after time of ovulation can trick the body to thinking the mare is pregnant and therefore the mare doesn’t return to oestrus. 4. Pregnancy During pregnancy, the mare has high levels of progesterone and low levels of oestrogen and therefore mares don’t show oestrus behaviour. Pregnancy being a sure-fire way of preventing mare-ish behaviour! If you are concerned about your mare’s behaviour, keeping a diary of events and behaviour will help establish whether there is a pattern to this behaviour and whether it coincides with oestrus or certain seasons. Discuss these matters with your vet who can help establish the cause and plan the best treatment option for your mare.