"Disease, Sex And Genetics And Their Effect On Pre-Weaning Survival"
Published:June 26, 2014
By:Paul Walker Thompson
“Disease, Sex And Genetics And Their Effect On Pre-Weaned Piglet Survival”
By: Paul Walker Thompson
June 25, 2014
Disease
Because the neonatal piglet is immunologically immature at birth, it is dependent on its dam’s colostrum for passive immunity in the form of antibodies, especially Immunoglobulin-G (IgG).
Maximum absorption of colostral antibodies occurs within the first 12 hours of life, and completely stops at about 48 hours of life. Failure to get the required amount of passive immunity sets the piglet up for possible disease invasion.
Disease Protection and Energy Intake are reduced when colostrum intake is reduced.
Proper Sanitation and Biosecurity are important factors in reducing disease causing organisms which can cause high mortality in nursing piglets for short periods of time.
A Proper Environment is important because a chilled piglet is more likely to suffer a challenge from disease(s). On the other hand, disease itself can cause hypothermia in the nursing piglet.
If a piglet is experiencing hypothermia due to a disease challenge, it will most likely seek warmth from the sow’s udder, but will usually be weak and lethargic, and thus more likely to be laid on by the sow.
Diseases that cause scours in piglets (Rotavirus, Clostridium difficle, PRRS and sometimes Escherichia Coli, Costridium perfringens, Streptococcus species, Coronavirus, and TGE) can cause morbidity and even death to neonatal piglets.
Sex
Female neonatal piglets appear to be a bit more durable, as they have a higher survival rate than male neonatal piglets, especially in large litters.
Male neonatal piglets temporarily loose time nursing once they have been castrated, and they are more susceptible to being weak, stillborn, getting chilled and being laid on.
It is possible that the stress of the process of castrating males may predispose them to disease challenges.
Male piglets have more cortisol in their metabolism, which may make them more susceptible to stress, which in turn may lead to more disease challenges than the female piglet.
It is possible that male piglets are drawn to pheromones put off by the sow’s udder, and thus are more likely to be crushed.
Genetics
The authors hypothesize that “Maternal Ability” of sows has most likely been bred out of the modern sow and increased the incidence of crushing. This is in contradiction to the first part of their article (i.e. the Introduction) that stated the National Pre-Weaning Death Loss decreased from 35% in 1928 down to 9% in 1995!
The authors demonstrate the great “Mothering Ability” of the Chinese bred, the Meishan. However, the Meishan produces primarily a fatty carcass, with very little lean.
There appears to be a difference in the amount of crushing of piglets by the different U.S. pork production breeds.
Apparently Modern Breeding Schemes have not emphasized “Maternal Ability”, choosing instead to emphasize Growth, Pigs Born Alive, and Number of Pigs Weaned.
Crossbreeding, and the heterosis it brings with it, appears to increase Piglet Survival Rate by up to 6% over that of purebred litters.
Selection for lean producing sows has a high negative correlation to daily fee intake, which may predispose lean sows from being able to eat enough food required to adequately milk large litters.
As we can see, Disease, Sex and Genetics all can have a great effect on Piglet Survival.
References:
Lay, D.C. Jr., R.L. Matteri, J.A. Carroll, T.J. Fangman and T.J. Safranski “Preweaning survival in swine” j. Anim. Sci. 80(E.Suppl.1)
pages 77-78, 82.
