Reproduction Flashcards
When do commercial and miniature swine reach sexual maturity?
3-7 months of age, 4-6 months for miniature breeds.
What is the average litter size of commercial and miniature breeds? At what parity is litter size smallest and largest?
Commercial: 8-12
Miniature: 4-6
Smallest at first parity, peaks between 3-7th, then stabilizes or decreases.
What is the average length of the swine estrous cycle? How long is estrus?
21 days (17-25 days). Estrus lasts 48h (1-3 days)
What signs occur prior to estrus and during estrus? Is silent estrus common in swine? How can estrus detection be facilitated?
Prior: Vulvar reddening and swelling, mucous discharge, nervousness, and increased activity
During: Sows stand immobile when pressure is applied to rump
Silent estrus common, but detection improved with presence of boar
Optimal fertilization rates occur when insemination takes place at what time? When do commercial producers usually breed sows? What is an additional advantage of this method?
Insemination takes place 12h prior to ovulation. As it is difficult to determine when ovulation will take place, commercial producers usually breed twice during estrus. Litter size increases with multiple matings during estrus.
Describe pen mating and hand mating.
Pen mating: Sow and boar left together during estrus
Hand mating: Sow and boar are placed in same pen at 12- to 24-h intervals until female is no longer receptive.
How do conception rates of AI compare to natural service? When are sows typically AI’d?
10-15% lower compared to natural service. Typically inseminate 10-30 hours after the beginning of estrus.
What is the first sign of pregnancy? How does a pregnant sow’s activity level change? How accurate is estrus detection?
Failure to return to estrus in 18-24 days following mating. General activity decreases with increases in inactivity and time spent sleeping. 98% accurate in determining pregnancy status after failure of conception or death of a litter.
When can ultrasound detect pregnancy? What is doppler ultrasonography used for?
Not prior to the fourth week of gestation. Reliably between 30-90 days. From four weeks on to determine litter size and fetal viability.
What progesterone concentration is typical of a non-pregnant female? At what day is an elevated progesterone concentration indicative of pregnancy? What hormone is more accurate for determining pregnancy status than progesterone and when does it peak?
<1 ng/mL on days 17-19. Day 18 after breeding. Estrone sulfate, produced by the fetus, which peaks at 23-30 days gestation.
What type of placenta do swine have? What does this require?
Diffuse epitheliochorial placenta. Requires colostrum for maternal protection of piglets from infectious agents.
What signs indicate impending parturition? At what times?
Typically during last week of gestation. Vulva become swollen and red during last 3-4 days. Development and distension of individual mammary glands during last 2-3 days of gestation, with expression of drops of clear or straw-colored fluid. Abundant milk can be expressed at farrowing; the interval between initiation of milk flow to parturition is typically 6-12 hours. Increased resp rate is most reliable.
What behavioral changes precede farrowing? When?
Restlessness and nesting with frequent urination, defecation, and chewing or biting on surrounding objects within 24 hours of farrowing. Just prior to birth, this activity diminishes and sow becomes recumbent.
Is use of farrowing crates typically necessary?
No, sows should be placed in a quiet room in a stall with abundant bedding material.
What type of bedding material should be provided to sows? Why
Abundant. Wood chips are ideal as they allow sow to engage in nesting behavior and maintain neonates body temperature.
