Merck Manual

Please confirm that you are a health care professional

honeypot link
Measures of Reproductive Performance in Swine Relative to Industry Averagesa

Measures of Reproductive Performance in Swine Relative to Industry Averagesa

Industry Data

Measure

Explanation

Below Average

Average

Above Average

Weaned sows bred by 7 days (%)

Percentage of sows bred within 7 days of weaning

<84%

86%–90%

91%–95%

Wean-to-service interval (days)

Days from wean to first service (may be extended in summer and fall and by parity 1 sows)

≥7–10 days

>6.0–6.9 days

4.5–6.0 days

Repeat services (%)

Percentage of sows reserviced within a wean group

≥9.0%–14%

5.1%–8.9%

2%–5%

Multiple matings (%)

Percentage of sows receiving multiple services (will be lower in single-service timed artificial insemination programs and can change with wean-to-service interval)

≤88%

90%–94%

95%–99%

Regular returns to service, 18–24 days (%)

Sows with a regular return to estrus (18–24 days)

≥9%–13%

5%–7%

1%–4%

Irregular returns to service, 25–37 days (%)

Sows with an irregular return to estrus (25–37 days)

>5%

2%–3%

<2%

Abortions (%)

Percentage of pregnant sows that abort

>3%

1.5%–3.0%

<1.5%

Not in pig (%)

Percentage of sows that reach full term, presumed pregnant, but do not farrow

≥2.1%

1%–2%

0.5%–0.99%

Day 30 conception rate (%)

Sows bred diagnosed pregnant by use of ultrasound

<85%

88%–92%

>92%

Farrowing rate (%)

Percentage of sows mated that farrow

<82%

83%–87%

88%–95%

Total pigs born/litter

Total number of pigs born per litter farrowed

<13.5

13.9–14.9

15.0–16.0

Live pigs born/litter

Number of live-born pigs per litter farrowed

≤12.6

12.9–13.9

14.0–15.0

Stillbirths (%)

Percentage of total pigs born that are stillborn (changes with litter size)

≥8.0%

6.0%–7.8%

<4.0%–5.99%

Number of stillborn pigs per litter

Number of stillborn pigs per sows farrowed

≥1.2–1.5

0.91–1.1

0.5–0.90

Mummified fetuses (%)

Percentage of total born pigs that are mummified (may increase as total born litter size increases)

≥3.0%–4.5%

1.0%–2.99%

≤0.7%–0.9%

Number of mummified fetuses per litter

Number of mummified fetuses per sow farrowed

≥0.5–0.6

0.3–0.4

0.1–0.2

Pigs weaned per sow farrowed

Based on calculation; measures may change if including nurse sows

≤9.8–10.8

11.0–11.5

≥11.6–12.2

Nonproductive sow days range

Measure will increase if data includes days from gilt entry until service

>56–74 days

42–50 days

≤30–38 days

Replacement rate (%)

39%–50%

52%–59%

62%–73%

Culling rate (%)

26%–37%

40%–47%

51%–65%

Sow mortality (%)

Includes sows that die or are euthanized

≥13.5%–16.8%

10.4%–12.4%

6.7%–9.4%

Weaning age range (days)

Excludes nurse sows

17.5–19.5 days

20.1–20.9 days

21.3–23.1 days

Gestation length (days)

May change based on use of induction of farrowing

<114.5 or >116.5 days

115.9 days

116.0 days

aValues are based on breeding-herd record summaries from 2019 and include data from ~1,500 farms; the average herd size was >2,000 sows, representing fertility data for >2.5 million sows. Reference sources: MetaFarms, Production Index Analysis 2019; Swine Management Services, LLC; PigCHAMP, 2019 Benchmarking Summaries, USA.