Practical approach to the sick neonate

The key to success with the newborn foal is to understand what is normal and to immediately act upon anything that deviates from this as time is of the essence if sick foals are to be saved. The key therefore revolves around ATTENTION TO DETAIL. Minor changes in behaviour can be warning signs of impending illness and the sooner treatment is started, the more likely there will be a positive outcome. The normal gestation of a horse is between 320-340 days but can be significantly more or slightly less than this. Immediately after birth, the cardiorespiratory system must adapt to extrauterine life.

Breathing

Spontaneous breathing should begin within 1 minute of birth, although many foals attempt to breathe as soon as the chest has passed through the pelvis. Whilst adaptations to extra-uterine life occur, respiratory rates are normally >60 breaths per minute but should decrease to 30–40 breaths per minute within a few hours. The foal may appear slightly blue at birth, but should resolve within a few minutes.

Cardiovascular system

The heart of a normal newborn foal should have a regular rhythm and the rate should be greater than 60 beats per minute after the first minute. Occasionally rhythm disturbances can be auscultated but should resolve within 15 minutes after birth. Murmurs may be heard in the first week of life, but should resolve beyond this time. A continuous or systolic murmur may be heard for the first few days after birth in the third or fourth left intercostal space and is due to a patent ductus arteriosus. Other systolic murmurs, thought to be flow murmurs, may also be auscultated. Murmurs that persist beyond the first week of age, those that are loud (>3/6), or associated with clinical signs should be further investigated. Mucous membranes should become moist and pink within a few minutes of birth.

Normal responsiveness

Foals are usually unresponsive whilst in the birth canal. As the foal is born, it should possess a righting and withdrawal reflex. Menace response is absent at birth and has a learned component and as such may not be present until 7-10 days. Thus, it should not be used to assess vision. Foals should have a strong suck reflex within 10 minutes of birth. However, try not to allow foals to suck fingers as they ingest organisms present on human skin, which can be pathogenic. Within 1 hour of birth, foals show evidence of being aware of auditory stimulation evidenced by movement of their ears. Eyes are angled slightly ventromedially at birth (similar to what would be seen in lightly anaesthetised small animals) and the eye angle gradually becomes more dorsomedial over the next month.

Foals should attempt to stand within 20 minutes of birth and most can stand unaided by 1 hour. They should then be steady enough and driven to nurse by 2 hours. Some foals will pass their meconium (first faeces) shortly after standing, but other will not defaecate until they have consumed colostrum approximately 3-4 hours after birth. Urination is more variable - fillies usually urinate before colts.

Foal resuscitation

For foals with difficulties, it is important to recognise and institute appropriate resuscitation procedures speedily. A scoring system (modified Apgar) has been developed as a guide to help effectively implement resuscitation and estimate the level of fetal compromise. A combined score of the four parameters of less than 3 should initiate cardiopulmonary resuscitation. If the score is between 4-6, then the foal should be closely monitored as it is suggestive of some degree of asphyxia.

The priority in resuscitation of the newborn foal, assuming that there are no other life threatening abnormalities present, is to establish an airway (A) and breathing (B) pattern. The upper airway should be cleared of membranes or any fluid. If the airway is suctioned, it should be performed with care. Tactile stimulation (stimulating the nose or ear) can be attempted initially. If this is not successful, then ventilation should begin. Usually the two options available at birth are mouth-to-snout resuscitation or the use of an Ambu bag. Evidence suggests that room air is as good, if not preferred to, 100% oxygen. Respiratory rate should be 10-15 breaths per minute.

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