REVISITING THE BASICS OF BREEDING

Posted in: Pork Insight Articles, Production, Uncategorized by admin on May 10, 2017

With traditional, intracervical artificial insemination (AI), 2 to 3 inseminations/estrus period are performed with each AI requiring 3 to 5 minutes. Individual AI doses contain 1.5 to 3 billion sperm cells in a volume of 70 to 85 mL. However, a significant proportion of sows in estrus on commercial farms are now bred 2 to 3 times using post-cervical AI (PCAI) with each AI dose containing approximately 50% of the sperm cells and volume that doses contained previously. With PCAI, semen is deposited just inside the uterus, requiring 10 to 15 seconds.

Regardless of whether intracervical AI or PCAI is employed, proper timing of inseminations is a prerequisite for high farrowing rates and large litter sizes. Reproductive performance in sows is greatest when semen is deposited 0 to 24 hours before ovulation (Soede et al., 1995)

PROPER DETECTION OF ESTRUS IS KEY FOR REPRODUCTIVE SUCCESS

• The ability to accurately detect estrus, particularly in gilts, is perhaps the most important factor impacting reproductive performance and longevity on sow farms
• Having a designated person for detecting estrus and breeding gilts has been listed as a key factor in wether or not sows are high or low longevity
• Estrus can only be confirmed, by display of the lordosis or immobilization response
• Daily boar exposure (10 to 15 minutes) commenced at 160 days of age, gilts given direct contact with a boar after movement to an estrus detection pen were significantly younger at first estrus (180.9 days of age) compared with gilts given fence-line contact only (191.9 days of age),
• Age of boars used to detect estrus is important, beginning at approximately 10 months of age.

SINGLE, FIXED TIME ARTIFICIAL INSEMINATION

A new product called OvuGel is labelled for inducing ovulation in weaned sows by stimulating the release of luteinizing hormone. Sows receive intravaginal treatment with OvuGel 96 hours post-weaning, and ovulation occurs 40 to 48 hours after treatment (Knox et al., 2014). Thus, when using OvuGel, a single fixed time AI (FTAI) can be performed approximately 24 hours after treatment. In theory, sows can be bred without regard to estrus.

• In order for OvuGel to be effective at inducing ovulation, treated animals must have an available crop of mature ovarian follicles.
• P.G. 600, has been demonstrated to accelerate the onset of follicular growth, estrus and ovulation in sows weaned during the summer (Bates et al., ).
• After first mating, a greater proportion of control sows (24.8%), compared to P.G. 600-treated sows (12.0%) returned to estrus.

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