Stillbirths in Pig and its Managements
Stillbirths are usually recorded as such when they are found dead behind the sows. A good target level for stillbirths is 5 % of total piglets born. At this level there is no point in carrying out investigations because it is unlikely that external inputs can alter the situation. However once the level reaches beyond 7 to 10% it is worthwhile carrying out an investigation by records and post-mortem examinations for infectious diseases.
Types of stillbirths are of 3 types:
1. Pre partum deaths: the piglets die before the end of gestation. The cause may be different infection. A pig herd with more then 7-10 % stillbirth may be suspected to be affected by infectious disease (i.e Enteroviruses,Circovirus,Parvovirus,PRSS ,Leptospirosis etc).
2. Intra-partum deaths: these piglets die during the process of parturition. May be due to non-specific causes and may be influences by duration of farrowing, litter size etc
3. Post-partum death: A piglets that dies just after the farrowing.
Causes of stillbirth in pigs:
1. Infections: a) Aujeszky’s disease. b) Enteroviruses. c) Eperythrozoonosis (Mycoplsma suis). d) Erysipelas. e) Leptospirosis. f) Mycotoxicosis(mainly zearalenone). g) Parvovirus (sequential to the delivery a mummified pig). h) PRRS. i) Circovirus (PCV2) j) Toxoplasmosis k) Reovirus l) Swine influenza virus .m) Streptococcal infections also have been implicated as a cause of stillbirth. n) Japanese encephalitis
2. Anaemia (Sow’s with Hb content of 9mg/100ml blood farrows more stillbirth)
3. Malnutrition’s
4. Mismanagement
5. Poisoning
6. Prolonged farrowing Risk factors associated with stillbirth piglets:
These factors can be categorized as genetic, maternal, piglet and environmental factor but also interactions exist between several factors (Vanderhaeghe et al.,2013).
The following factors need to be considered as causal or contributory factors to the stillbirth:
1. Stillbirths increase with the increasing age of the sow and beyond 5th parity may reach 20%.
2. Stillbirths occur more in larger litters then smaller litter size. Johnson et al.(1999) concluded that selection for sows with larger litters will increase the number of still births piglets per litter.
3. They are more common in pure breeds then crossbred. there is a small but significant genetic influence on stillbirth(knoll et al., 2002)
4. The mean interval between two piglets birth is 12-15 minutes and normal time may vary from 2-5 hours (Bazer and First.1983). Sows that have prolonged farrowing will have a higher number of stillbirths.
5. Farrowing house temperatures above 30ºC during days 102-110 of gestation increase the risk of stillbirths (Sprecher et al,.1974).
6. Sows with uterine inertia produce high numbers of stillbirths.
7. Sow associated with calcium deficiency produce high numbers of stillbirths.
8. Anoxia and high carbon monoxide levels in the air associated with faulty gas heaters can raise stillbirth rates significantly.
9. Piglets found dead behind the sow after birth related to hypothermia.
10. Lack of exercise may have an effect on the stillbirth rates in pig farm.
11. Diseases of the sow such as fever, mastitis, septicaemia, acute stress or haemorrhage also produce high stillborn piglets.
Clinical signs:
Stillborn piglets are found dead in the membrane behind sow or delivered dead as a result of assistance at farrowing or uterine inertia during prolong farrowing. The cause of death may be congenital and the piglet may be malformed or very small to be viable. Culture or demonstration of infectious agents may suggest a cause. Animals which are die for carbon monoxide poisoning is often cherry red colour. Oversize foetuses may delay parturition and are often born dead. Presence of dead piglet or a mummy in front of the piglet concerned and the delay caused can deprive it of oxygen and kill it.
Post-mortem lesions:
If the pig dies before farrowing, then depending on how long before, it will show varying degrees of post mortem or degenerative changes including discoloration of the skin and loss of fluids. If death occurs in the early stages of pregnancy a fully-formed mummified pig will be seen. A pig that dies during the process of farrowing or immediately afterwards will be fresh and normal. Stillborn piglets have a fleshy cord, membrane on the skin and cartilaginous curled up tips to the toes (Fig.1). The piglets stillborn can be differentiated easily by post mortem examination.
1. The chest is opened and the lungs and the trachea examined to determine whether the pig had breathed, i.e. born alive and then died.
2. The lungs of the true stillborn pig are a dark plum colour, showing none of the pink areas associated with inflation and breathing, resemble like liver (Fig.2) and sink in water. Pigs that attempt to breath during the process of farrowing will also show evidence of mucous obstructing the wind pipe.
Treatment:
If uterine inertia is occurring remove foetuses manually as soon as possible until normal farrowing continues. If calcium deficiency in the sow suspected, give calcium borogluconate into the ear vein and treat any other illness in the sows. Compromised piglets may be resuscitated by clearing the membranes from the mouth, nostrils, massaging the chest or swinging the piglet by the hind legs to stimulate breathing.
Management to reduce stillbirths
Where stillbirth levels are high it is necessary to eliminate disease as a possible cause and then identify the predisposing factors and their relevance. Most stillbirths in the absence of diseases or environmental faults are related to age, individual sows and large litters.
1. Vaccination of pig against infectious diseases.
2. Do not let the age of the herd spread beyond the fourth partum.
- Identify problem sows. Observe farrowing behaviour. 4. Look at breed differences. 5. Check farrowing house environments and ambient temperature. 6. Check farrowing pen designs. 7. Monitor farrowing and assistance if needed. 8. Interfere early in prolonged farrowing. 9. Give good management at farrowing. 10. Provide a heat source behind sow at farrowing. 11. Examine the herd records register. 12. Check haemoglobin levels in sows. 13. Check for blood parasites and parasite levels. 14. Check for diseases in the sows. 15. Check for sow nutrition condition.
CONCLUSION
Stillbirths are a worldwide problem in pig farming which mainly affect newborn. Stillborns in the absence of diseases or environmental faults are related to age, individual sows and large litters. Significance if stillbirths are more than 7 to 10 %.
PIG FARMING IN INDIA
Compiled & Shared by- This paper is a compilation of groupwork provided by the Team, LITD (Livestock Institute of Training & Development)
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