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Small Litter Size: Describing the Problem From The Farm’s Perspective. David K. Bishop dbishop@sampsoncc.edu Sampson Community College. Season: Physiological Changes. In most animals, exposure to conditions that cause the body temperature to increase causes
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Small Litter Size: Describing the Problem From The Farm’s Perspective David K. Bishop dbishop@sampsoncc.edu Sampson Community College
Season: Physiological Changes • In most animals, exposure to conditions that cause the body temperature to increase causes - a decrease in gonadotropins; and - a decrease in feed intake.
Lifetime Performance: Genetics + Environment 29,000 gilts
Dealing with Weaned Sows: “as Delivered” • Condition Scores • Regular Patterns of introduction • Some program for “Knotheads” • Maximum performance • Fertility- Typical measures • Farrowing Rate • Born-Alive • Fecundity- Maximum Pigs per mating • Avoid the negative impacts of “outliers”
Reproductive Failures Associated with Animal Welfare • Weaned sows that Fail to return within 7 days • Gilts / Sows that are/go Anestrus • Chronic Embryo Losses after Preg Check • Timing Issues due to intensity of expression • Improper use of hormonal therapy
Effect of ambient temperature on lactation feed intake and body weight loss 12.5 11.9 10.8 9.9 6.8 J. Anim. Sci. 77:2124-2134, 1999.
Maximize Lactation Length on Sows for subsequent Litter Size as long as she has enough Body Condition to Initiate Cycles when Weaned
The Effect of Late Insemination on Farrowing Rate a b c d a Vs. b P < .05 c Vs. d P < .01
a b a b The Effect of Late Insemination on Litter Size a Vs. b (P < .05)
The Effect of a Late Subsequent AI on Reproductive Performance • The benefits of multiple AI are lost when the last AI is performed during too late. • Sows with Lower fertility have: • Susceptible to infections (at or before mating) • Decreasing uterine contractility (poor semen movement from the AI bag) • Physiological post-breeding inflammatory response (16-84 hours after mating) • Higher incidence of Late returns to Estrus (< 3:1 Ratio)
Late AI Endometrium Vessels Cervix - SP PMNs Inflammatory Products C` & HSF ****** Uterine Contractions + SP AI in Swine: Proposed Role of Post-breeding Inflammation for Late AI
Predictability of < 7 Born Alive Large Scale operation for one year Litters < 7 varied from 5 % to 22% Placed average of 11 pigs per sow If sow lost 2 pigs (7-14 days) -- 34% had < 7 born alive in next litter If the reason was scours--- 68% had < 7 in subsequent litter
Farrowing Rate: Born-Alive Effective Management Style Mandate Response Deviations
Typical Born-alive per Room 16 12 11 9 11 9 8 10 12 11 23 11 10 9 14 12 15 13 12 9 8 7 11 12 10 9 8 11 13 11 10 13 11 10 10 24 16 13 15 18 9 11 12 10 9 11 11 12 14 10 15 0 3 2 4 4 2 0 0 5 6 10 14 11 11 12 13 12 85% of Group = 11.91: 100% of Group = 10.54