Three months, three weeks, and three days. That, as the old saying goes, is how long it takes to make a litter of pigs.
Because all months are not created equal however, figuring out a sow’s due date isn’t always quite that simple. In fact, it rarely is. Three months, three weeks, and three days only works out to the official length of a full term pig pregnancy — 114 days — if all three of those months contain thirty days, rather than, say, thirty one or twenty eight. And since only four of the twelve months in any given year actually contain thirty days, you might imagine how often a good calendar and day-by-day count of the gestation comes in handy.
Of course, pigs don’t always deliver when they’re supposed to either. They’re not as prone to early and late labors as some animals — humans, for instance — but a day or two here and a day or two there, does occasionally happen. Especially, as the sow pictured above with a fresh batch of pigs can attest, if there’s a good winter storm to be had in the coming week. Why deliver when it’s forty and sunny when one can wait until it’s twenty-five with a cold rain?
The official consensus is that most healthy litters arrive between 111 and 116 days after conception, but as you can see from Bridget’s wily bunch born last night at 117 days, rules are made to be broken.
Why do sows and gilts go overdue?
How long is a string? There are probably almost as many reasons for a sow to go longer than her due date as there are sows who do so, and those reasons can range from simply carrying a small litter, to serious health complications. In most cases, an overdue sow is nothing to worry about, but every once in a blue moon a farmer may have to take matters into his or her hands, rather than letting nature take its course. Nature, as we so often tend to forget, can be cruel.
How long is too long?
As with human pregnancies there are few truly hard and fast rules, generally speaking however, anything beyond 117 days is probably pushing it. Before you take any action though it’s important that you are absolutely certain how many days it’s been since mating. If a sow has been artificially inseminated it’s very easy for a farmer to know how far along she is, and that goes for sows who have been hand mated with a live boar as well. But for sows who have been penned with boars for extended periods, sometimes, even if we think we know, we don’t really. Because pigs come into estrus once every three weeks it’s not uncommon for beginner hog farmers to mistake a gilt or sow’s due date by one estrus cycle and begin to fret when the pigs aren’t even due for another twenty one days. Once you’re absolutely sure of a due date, if there is no signs of pigs for three to four days you may want to contact your veterinarian for a professional opinion.
The reason for the 118 day cut off is two fold. If we were to compare pig gestation with human gestation, every three days would be equal to one week, which means at 118 days the sow is now the equivalent of more than one week overdue. At this point the pigs are growing quite rapidly and every day overdue they continue to grow in utero increases the chances of delivery complications due to their size. In a first farrowing gilt this is an especially important consideration, in a third parity sow it may not be as big a factor. Also, for every day past 118, the chances of in utero complications that result in the death of piglets before they’re born. When a pig dies in utero and is not immediately expelled it begins to decompose, leading to the potential for a life-threatening infection for the sow.
When should you intervene?
Prior to 118 days, and even sometimes shortly thereafter, as long as the sow is not in distress, the pigs are active in utero, and there is no virulent discharge from the sow’s vulva it is best to allow nature to take its course. Signs that you may need to intervene include:
- Prolonged distress in the sow with no apparent progression in the labor. Sows will often show distress by being extremely restless, getting up and down often, making pawing motions with their hind legs, nipping or biting at their own flanks, breathing heavily and rapidly, or walking in circles and sniffing or looking behind themselves.
- Green, foul-smelling, and/or virulent discharge from the sow’s vulva.*
- Inactivity in the piglets for more than 12-24 hours when you could previously feel or see activity frequently.
How Should You Intervene?
Because much of the care of livestock in emergency situations is extremely nuanced it’s best to seek help from an experienced friend or veterinarian where possible. When or if help is not available however, the first step is to check the sow’s birth canal for obstructions and cervix for dilation. National Hog Farmer magazine has a truly amazing set of printable posters for hanging in your barn or farm office. One of those posters is the “See What You Feel Delivery Poster” which shows a mock-up cut-away of a sow’s birth canal to help visualize what you’re feeling.
In cases where the sow is in distress it may be as simple has removing a large, stuck pig from the birth canal to allow others to pass. Where a sow is not laboring properly however, it may be necessary to administer medication to help move things along. In this case it is always a good idea to consult with your veterinarian for dosing information if you’ve never handled a similar situation before. In swine Lutalyse can be used to help labor along, but oxytocin should never be administered prior to the first — and preferably the first few — pigs being passed. Oxytocin will encourage placental detachment and if the pigs cannot pass as this happens they will drown and/or suffocate in utero.
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This post is part of the Hog Farming 101 series on bringing bacon into the world. For more posts about raising hogs click here.