OLDS, Alta. – Hog sense is the best guarantee of successful pregnancies among pigs.
About 80 percent of North American pigs are artificially inseminated and often infertility can be traced back to improper management of females and semen, said swine specialist Sasha Gibson. Originally from England, she works with large pork producers in Minnesota as a reproductive consultant.
“When you do the same thing every day, you get complacent,” she said in an interview at a farmer meeting in Olds.
She explained artificial insemination is part of a good herd health plan. There is less variability in breeding results and less risk of infection and sickness among females.
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Artificial insemination also makes more efficient use of boars. Each ejaculation can provide 24 doses of 80 grams each, thus allowing more females to get bred.
Successful conception starts with proper semen storage.
When the semen is delivered, it must go into a controlled environment immediately at a constant temperature of 16-17 C. Poorly maintained coolers that break down cause semen losses. Larger farms of more than 600 sows should have two coolers so packages can be less tightly packed with better air circulation. More than one cooler also provides a backup machine in case of breakdown. She suggested installing an alarm system that triggers a warning if a cooler shuts off.
“Think about the cost of semen and the losses if it is not stored properly,” she said.
Coolers should be kept about 10 centimetres away from a wall and away from windows if possible.
Coils at the back might be pushed against the wall, get damaged and stop working. An oscillating fan at the back can also cool the coils. Ultraviolet rays shining through windows can destroy semen.
Coolers need to be cleaned once a week. Dust and bacteria can contaminate supplies.
“If you wouldn’t lick it, it isn’t clean enough,” she said.
Turn the semen twice a day and organize the doses so older packages are used first. Those working with females need to correctly assess the stages of estrus.
A female cycles every 21 days and goes through recognizable stages. Estrus is when she is receptive to a boar for 10-15 minutes at a time.
Sows in heat stand still, stare straight ahead and have a shiny red vulva on the inside of the lips. They may also urinate, shake, tail twitch or groan. They may return to heat because they did not ovulate the first time or the semen quality was poor and they failed to settle.
Breed gilts in their second heat, or when they are 220 days old. They are likely to have fewer pigs if they are bred during their first heat.
“To get the best from AI, let the sows show you what they want.”
Fertility problems may occur because the technician misjudged the signs of heat and the female was not quite ready to be bred.
She may fail to get pregnant if stressed by new neighbours, new surroundings or not enough feed.
Sows can also absorb or abort pigs. This often happens due to stress or illness. Embryos can be reabsorbed but in an abortion, muscle tissue and skeletons may be observed.
Boars are vital to a successful pregnancy. A farm should have four working boars that can be rotated every day. Sows need to see, touch and smell them to improve chances of pregnancy.
“Boars need to breed to be boar-like. Testosterone goes down and your boar becomes less smelly,” she said.
Natural semen lasts about 72 hours in the reproductive tract compared to collected semen’s 48 hours.
Technicians need to observe simple health rules. They should wash hands regularly or wear gloves when inseminating sows to prevent infections. Also, the catheters used for injecting semen need to be kept clean.
