Because the nature of outdoor pig production does not allow close supervision of young piglets on the sow, in the way that can be done in farrowing crates indoors, it is often more difficult to identify the most significant causes of death in the newborn pig.
Moreover, it is even difficult to know exactly the levels of death, the only figure available that is verifiable is the numbers weaned. Stillborn pigs and those dying in the first 24hrs of life may be eaten by the sow or buried within straw bedding meaning their existence may never be known to the stockman. An outdoor herd with low weaned/litter productivity presents the challenge to ascertain whether it is a breeding problem (producing low litter size) a farrowing related problem producing unfound stillborn pigs or a lactation husbandry problem causing high mortality. Consolidated herd records suggest that UK outdoor herds produce both less pigs born alive and higher piglet mortalities limiting overall weaning numbers compared to indoor herds.
Stillborn pigs and those dying in the first 24hrs of life may be eaten by the sow or buried within straw bedding meaning their existence may never be known to the stockman. An outdoor herd with low weaned/litter productivity presents the challenge to ascertain whether it is a breeding problem (producing low litter size) a farrowing related problem producing unfound stillborn pigs or a lactation husbandry problem causing high mortality. Consolidated herd records suggest that UK outdoor herds produce both less pigs born alive and higher piglet mortalities limiting overall weaning numbers compared to indoor herds.
However, certain principles can be applied that provide the basis for reducing losses. When born, there is a dramatic drop in the temperature to which the piglet is exposed. Moreover, as it dries off, latent heat of vaporisation is extracted from the piglet with the result that body temperature falls. This hypothermia can only be offset:-
a) by reducing the heat loss
b) by the piglet burning energy to maintain body temperature
In the absence of active management techniques such as drying and use of infra red lamps such as may be used in the tpical indoor farrowing facility, the outdoor born pig can only rely on warmth from mother and the warming and drying effects of the bed. Huddling together will also preserve heat.
Features of the bed which will affect heat loss include:-
1) Quantity of straw - there is a very fine art to bedding outdoor arcs. Too little and the piglets chill; too much and small piglets become entangled making them vulnerable to crushing by the sow.
2) Quality of the straw - short chopped barley straw that is clean, dry and fresh provides the best medium.
3) Dampness - the wetter the bed, the greater the heat loss. At wet times of the year, there is a balance to be found between providing a new bedded area that is clean on wet ground. Normally arcs should be moved to a new site for each farrowing with old beds either lifted and removed or burnt in situ. Some producers, in wet conditions, may prefer to add new bedding on top of the old but this should only be limited to one off situations. Lying boards may be used in extreme circumstances.
4) Frequency of bedding - allowing the sow a week to settle the bed prior to farrowing should be followed up with daily addition of clean straw; bare in mind that the sow may eat some of it.
5) Draughts - orientate arcs away from prevailing winds and always ensure there are no gaps around the base. Either pack straw at the base of the arc from the inside or earth up around the outside. Doors closed during farrowing may also help as may the tight fitting of the fender.
Conversely it should be borne in mind that in very high ambient temperatures a deep compacted straw bed will limit the sow's ability to dissipate heat leading to overheating, likely to raise stillbirth levels, desertion from the arc rendering new born piglets more vulnerable or disturbance of the bedding. In extremely warm conditions reduction of bedding material maybe appropriate but a fine balance is still required between the needs of the sow and the needs of the piglets at birth.
In exactly the same way as would apply indoors, increasing sow feed levels between weeks 13 and 15 gestation will boost energy reserves in newborn piglets, giving them a greater change to maintain body heat. An early suck of adequate amounts of colostrum is essential but the ability of the stockmen to influence this by assisted suckling, split suckling and fostering is more limited than in the indoor farrowing facility. Discuss with your veterinary surgeon or nutritional advisor the most appropriate strategy for your herd.
Chilling is the underlying feature of a large number of piglet deaths, both indoors and out. Not only can pigs die directly due to hypothermia, but chilled pigs tend to be slow moving, making them vulnerable to crushing and will not receive sufficient colostrum, making them vulnerable to infection in the first few weeks of life.
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