Yorkshire Pig Gestation Calculator

The Most Popular Commercial Breed

The Yorkshire (also called Large White) is the most widely used commercial pig breed worldwide, prized for excellent maternal traits, large litter sizes, good milk production, and lean, efficient growth in offspring. It's also a foundational breed in most commercial crossbreeding programs, often used as the maternal line crossed with terminal sire breeds like Duroc for market hogs.

The Yorkshire Breed: The White Maternal Line

The breed is named for the county of Yorkshire in northern England, where hog keepers in the 1700s crossed their large native white pigs with imported Asian stock to add early maturity and prolificacy. The result was a big, white, long bodied pig that fattened faster than the coarse local breeds it replaced. Britain and much of Europe register the same pig under its older name, the Large White, while North American breeders spent the last two centuries selecting a slightly longer, leaner frame, so the words describe one breed with two regional styles.

Two physical traits identify a Yorkshire at a glance. The first is the all white coat, an old market requirement that also makes the breed poorly suited to unshaded outdoor lots, since white skin sunburns easily. The second is a pair of erect ears that stand upright from birth, the feature that separates Yorkshires from their lop eared cousins, the Landrace, even though the two breeds are closely related and constantly crossed.

The phrase maternal line has a precise meaning in modern pork production. In the standard three breed system, Yorkshires are mated to Landrace to produce the crossbred mother gilt, valued for litter size, milking ability, and durability, and that gilt is then bred to a terminal sire such as a Duroc to produce market hogs. Every piglet in that system inherits half its genes from a Yorkshire grandmother, which is why the breed's mothering reputation shows up in carcass barns it never enters.

Large Litter Size & Mothering Ability

Yorkshire sows average 12 to 14 piglets per litter - a notably large litter size that's a core reason for the breed's commercial dominance. Well-managed, experienced sows can occasionally produce even larger litters. Yorkshire sows also carry a strong reputation for good mothering ability, including attentive nursing behavior and a lower tendency toward accidentally crushing piglets compared to some other breeds, which significantly improves piglet survival rates on commercial operations.

Feed Requirements During Gestation

Pregnant Yorkshire sows need a carefully managed gestation diet that avoids excessive weight gain (which can complicate farrowing) while still supplying adequate protein, energy, and minerals for the large litters typical of the breed. Feed intake is typically increased notably in the final third of gestation, when the majority of fetal growth occurs, and again sharply after farrowing to support milk production for 12-plus piglets.

Yorkshire Sow Gestation Specifics

The breed calculator above runs on the 114 day average, with farrowings inside the 112 to 115 day window considered fully normal. What surprises many first time producers is how little that clock moves. Unlike litter size, which swings widely, gestation length in Yorkshire sows barely responds to parity, season, or litter size, shifting by a day at most. That stability is why the old mnemonic still works as a planning tool for batching breedings into all in, all out farrowing groups.

Parity, meaning the number of litters a sow has farrowed, is where the breed's numbers really change. A gilt, a female farrowing her first litter, typically produces two to three fewer piglets than she will at maturity, and her piglets tend to be lighter at birth. Litter size climbs steadily through early parities and usually peaks around the third to fifth litter, when a well managed Yorkshire commonly farrows 13 or more live piglets. After that peak, performance plateaus and then slips, with later parity sows producing more stillborn piglets and smaller litters, which is why commercial herds often cull around parity six or seven.

Two other reproductive numbers matter for planning. Sows return to heat four to seven days after weaning, so a 21 to 28 day lactation sets the rhythm of the whole herd calendar. And because gestation is so fixed, the date you actually control is breeding: record it accurately, whether from a hand mating or an artificial insemination dose, and the 114 day countdown gives you the farrowing date with unusual confidence for a livestock species.

Year-Round Breeding

Unlike many seasonal farm animals, domestic pigs including Yorkshires are not strongly seasonal breeders and can cycle and be bred throughout the year, which is a major reason commercial pork production can run continuous farrowing schedules rather than a single annual season - a significant operational advantage over strictly seasonal livestock species.

Farrowing Preparation for Yorkshire Sows

Standard practice is to wash sows shortly before they move into the farrowing room around day 110 of gestation, a few days ahead of the earliest farrowings in the 112 to 115 day window. Washing removes caked manure and parasite eggs that a sow would otherwise carry into the crate and pass to newborn piglets, whose immune defenses at birth are minimal. Farrowing crates with side rails sit at the heart of the setup: they let a sow lie down slowly while the rails give piglets a split second to escape crushing, the single largest cause of preweaning death.

Piglets need a different climate from their mother. Newborns require a creep corner heated to roughly 90 to 95 degrees F with a heat lamp, while the sow is kept cooler, and training piglets to use that warm corner within hours of birth keeps them out from under her when she lies down. Have on hand obstetric gloves and lubricant, dry towels for rubbing wet piglets, iodine for navels, and a means to warm a chilled piglet quickly, because a cold piglet stops nursing within hours and deteriorates fast.

Most Yorkshire litters arrive over two to four hours, with piglets born every 10 to 20 minutes once labor is underway, so check the sow regularly but let her work. Call for help if strong straining continues for more than about an hour with no piglet appearing. Once farrowing finishes, make sure every piglet gets colostrum within the first few hours, and plan for fostering: with litters of 12 to 14 common, splitting surplus piglets onto a sow with a smaller litter is the standard way to make sure the whole litter thrives. Iron supplementation in the first few days is also standard, since sow milk contains almost none.

How Yorkshire Compares to Duroc and Landrace

See our general pig gestation calculator for all breeds.

Frequently Asked Questions

Sources & References

• Merck Veterinary Manual - Porcine reproduction

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