Larger litter sizes create animal welfare challenges because there are more and smaller pigs for farmers to manage
RED DEER — The modern sow is more prolific than ever but increased litter size carries consequences.
Selective breeding has resulted in four more pigs per sow per year in the past 13 years, said veterinarian Egan Brockhoff of Prairie Swine Health Services.
“There is no question larger litter sizes are associated with sow and piglet welfare challenges. There are simply more animals to manage and more small pigs to manage,” he said at the Red Deer swine technology workshop held in late October.
Stillbirths have increased in part because of the longer farrowing period.
Farrowing duration of hyper prolific sows has increased by 150 minutes.
The standard sow farrowing 10 years ago lasted three to five hours from the first to last piglet. Now the average farrowing length is seven to seven and a half hours and the sows become fatigued.
“We are asking these ladies to do a lot of physical activity. Giving birth is labour intensive,” he said.
There is a higher risk of piglets experiencing oxygen deprivation during these long farrowing periods. The result is more stillborns and more weak piglets that do not want to get up and nurse. Piglets also have a wider weight range of 400 grams to 1.5 kilograms. Piglets born weighing less than 1.2 kg grow nine percent slower from birth to slaughter compared to heavier pigs.
Another condition is intrauterine growth-retarded piglets, in which the piglets are fairly lightweight and have domed heads. There may also be retarded post-wean maturation of the gut.
The smaller ones fail to compete at the udder and their gut morphology is different from larger piglets. They have altered muscle and organ development. They struggle to warm up, show less vitality and have reduced immune responses.
Colostrum is vital.
“We don’t spend near as much time on colostrum in the pig industry as the dairy sector. We can’t milk sows in a simple way,” he said.
Colostrum gives piglets fat, sugar, protein, vitamins and minerals, as well as growth factors that drive development of a pig’s intestine. This affects its ability to grow. It helps warm the pig with unique brown fat properties that help with thermoregulation. It provides passive and acquired immunity.
By 12 hours after birthing, there is almost a 50 percent difference in colostrum quality because its potency has declined.
Colostrum production starts a couple weeks before birth so Brockhoff suggested trying to milk the sow and get it into the piglet right away so it receives mother’s milk. Colostrum can also be expressed from the teats during the birthing process.
A sow produces a limited amount of colostrum and the more piglets born alive, the more it has to be divided.
If cross fostering, move the piglets after they receive mother’s milk.
These newborns struggle to warm up so a farrowing room set at 20 C is cold. If they did not get enough colostrum, they suffer more.
Piglets need to get sucking within 15 minutes because the amount of colostrum is decreasing. After 48 hours, the piglet’s gut is no longer able to absorb immunoglobulin from colostrum.
Intake matters but it is hard to know how much a piglet has nursed. If it gets less than 400 grams in the first 24 hours, the death rate increases.
“If it consumes less than 200 grams, it has a six times greater chance of dying before it is weaned,” he said.
Birth order also matters.
The first born is likely to get a better producing teat at the front while the further down in the birth order, the less colostrum is available, especially for those nursing at the hind end.
Piglets are faithful to teat order and it is established in three days so they may need to be moved around to make sure they receive enough milk.
Probably 10 percent will try to use more than one but others are loyal to a teat, said Brockhoff.
“That means watching, counting, supervising,” he said.
Colostrum intake also influences lifetime productivity in the sow herd.
If a day-one gilt has not consumed enough colostrum, she will have reduced growth, greater age at puberty, fewer piglets born alive and reduced litter immunity.