engineering

Gestation crate

Gestation crate is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Gestation crate rather than just read about it. In short: A gestation crate, also known as a sow stall, is a metal enclosure in which a farmed sow used for breeding may be kept during pregnancy. A standard crate measures 6.6 ft × 2.0 ft (2 m × 60 cm).

Key takeaways

Gestation crate belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gestation crate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gestation crate from memory before moving on to harder problems.

Reference excerpt

A gestation crate, also known as a sow stall, is a metal enclosure in which a farmed sow used for breeding may be kept during pregnancy. A standard crate measures 6.6 ft × 2.0 ft (2 m × 60 cm). This is insufficient room for a sow to turn around. Gestation crates are associated with higher levels of injury and disease. They contain no bedding material and are instead floored with slatted plastic, concrete or metal to allow waste to drop below. This waste is then flushed into open-air pits known as lagoons. A few days before giving birth, sows are moved to farrowing crates where they are able to stand up and lie down, with an attached crate from which their piglets can nurse. Opponents argue they are a form of animal abuse, citing the detrimental effects of close confinement and the barren conditions. Supporters argue they are necessary to prevent aggression among sows housed together. Gestation crates are banned in the United Kingdom, Canada, Switzerland and Sweden, and in nine states in the US (Arizona, California, Colorado, Florida, Maine, Michigan, Ohio, Oregon and Rhode Island). The crates are banned for new installations only in Austria and Canada, so many sows are still confined there in pig breeding facilities. However, farrowing crates, in which female breeding pigs can be kept for up to five weeks, are not banned in the UK.

Usage

Pregnancy

Between 60 and 70 percent of sows are kept in crates during pregnancy in the United States. Each pregnancy lasts for three months, three weeks, and three days. Sows will have an average of 2.5 litters every year for two or three years, most of which is spent in the crates. They give birth to between five and eight litters before being slaughtered. Some older sows may reach a size at which they have to sleep on their chests, unable to lie on their sides as pigs usually do. The floors are slatted to allow excrement and other waste to fall into a pit below.

Birth

A few days before giving birth, sows are moved to farrowing crates, which are slightly wider so they can lie down to nurse. Crates have 18 in (46 cm) "troughs" on each side where the piglets can safely lie without being in danger of sow overlay (when the sow lies down on top of a piglet). Piglet survival also depends on selection pressure. Groups of piglets bred for higher survival showed no difference in mortality when weaned in farrowing crates and outdoor systems.

Piglet mortality Although farrowing crates have been used based on the assumption that they reduce piglet mortality rates, there is little published evidence in support of this claim. The most comprehensive publication to date on this subject concluded that there is no significant effect of housing on overall piglet mortality, the authors stating that "Despite the fact that the crate system has been considered to reduce piglet mortality mainly through a reduction of crushing, there is not much scientific evidence for this when considering the few large surveys that compare the mortality rate in commercial herds." The review goes on to describe several large studies dating from as early as 1983, the majority of which found no difference in piglet mortality rates between loose and crated sows. The review also details an argument as to why piglet mortality rates have been reported to be somewhat higher in a comparably small number of studies, citing methodological flaws.

Limitations on usage

Europe In the European Union, the crates must not be used after the fourth week of pregnancy following a 2013 EU Directive. Gestation crates are illegal at all times in the United Kingdom and Sweden, however farrowing crates are permitted in the UK. Denmark and Norway are some of the countries where gestation crates are still used in conventional pig farming operations.

New Zealand The use of gestation crates following mating will be phased out in New Zealand by 2015. However the crates are still legal for up to four weeks after farrowing. A review led by the Ministry for Primary Industries, in 2016, found that "The current code of welfare allows for up to 5% of sows to be retained in crates for a further week (following the 4 week maximum in crates post-farrowing) as nurse sows. This practice enables slowly growing or poorly performing piglets to be properly weaned. It has been noted that industry does not accept or comply with this requirement and some producers are exceeding both the maximum 5% of sows allowed to be retained for this purpose and the amount of time that they are being retained (i.e. greater than the one week maximum as stated in the code)." And "The current code requires that sows in any farrowing system constructed after 3 December 2010, must be provided with material that can be manipulated until farrowing (to allow the sow to perform nesting behaviour which she is extremely motivated to do). It has been noted by NAWAC during this review that industry disagrees with this requirement and does not comply with this minimum standard."

North America

In 2014 Canada instituted a nationwide ban on new gestation crates. This ban however has been delayed another 5 years until 2029 and will not include existing installations. In the United States, they have been banned in Florida since 2002, Arizona since 2006, and California since late 2008. A Rhode Island law banning the crates, passed in June 2012, took effect in June 2013. They are also banned in Colorado, Maine, Michigan, Massachusetts, Ohio, Oregon and Rhode Island. In California, Proposition 12 prohibits pork from gestation crates from being sold, even if they were produced elsewhere. As of 2013 New Jersey had a pig population of about 9,000 none of which, according to Humane World for Animals, are kept in gestation crates. In survey conducted in 2013, 90% of New Jersey voters were in favor of banning the crates. In June 2013, Governor Chris Christie vetoed S1921, a bill to ban pig gestation crates. which had passed in the General Assembly with a vote of 60–5 and the Senate 29–4. An attempt to override the veto did not come to a vote. In October 2014 the New Jersey Legislature adopted S998 with a vote in the Senate of 32–1 and in the Assembly 53–13 (with 9 abstentions) On 27 November 2014 Christie vetoed the bill. A new bill was introduced in 2020 and they were banned in 2023.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Gestation crate

Start with the simplest possible case. Write down what Gestation crate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Gestation crate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Gestation crate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Gestation crate

In research: Gestation crate appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Gestation crate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Gestation crate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures used to confine animals, Cruelty to animals, Ethically disputed business practices towards animals, so understanding it makes those chapters shorter.
In everyday life: Look for Gestation crate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Gestation crate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gestation crate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Gestation crate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gestation crate in simple terms?

A gestation crate, also known as a sow stall, is a metal enclosure in which a farmed sow used for breeding may be kept during pregnancy. A standard crate measures 6.6 ft × 2.0 ft (2 m × 60 cm).

Why does Gestation crate matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Gestation crate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Gestation crate.