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1. This document is Circular 320, one of a series of the Department of Animal Science, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published February 1982. Reviewed March 1999. Please visit the FAIRS Web site at http://hammock.ifas.ufl.edu. The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / Christine Taylor Waddill, Dean 2. K. L. Durrance, Former Professor and Extension Swine Specialist, and A. C. Warnick, Former Professor, Animal Sciences Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611. Circular 320 How To Profitably Increase Litter Size 1 K. L. Durrance, A. C. Warnick 2 Seventy percent of all production costs is represented by feed. The remaining 30 percent of production cost is largely determined by management skills. The most important single factor determining profit is litter size. In order to have a litter that is profitable, gilts must be selected and managed with care, blood tests and vaccinations should be administered at the proper intervals, and breeding should be well planned and supervised. (Table 1), (Table 2), (Table 3) A) Select gilts on following points Healthy individuals from a healthy herd Sound underline 14 or more prominent teats From lines and families with high fertility (large litter size) and early sexual maturity Structurally correct, with sound, large feet and sound legs (capable of carrying weight of the pig once weight gain occurs), and quality bone Large frame, loose made (with long, clean muscling), with rapid rate of gain and good feed efficiency At approximately 4 to 5 months old or 150 to 200 pounds From littermate records at Swine Evaluation Unit (Live Oak) B) Management of replacement gilts Feed 3 to 6 pounds of growing ration (15 percent protein content) for adequate gains Provide lush pasture where economically feasible: Winter -oats, rye, wheat, and clover Summer -millets and grasses Cull gilts that do not meet the criteria for developing into a sound sow C) Herd health Vaccinate for: Leptospirosis (at least two weeks before breeding) Erysipelas (pigs at 8 to 12 weeks and sows 2 weeks before each breeding season) Atrophic Rhinitis (gilts 6 weeks and 2 weeks prior to farrowing, sows 4 weeks prior to farrowing, boars twice annually at 3 week intervals, and pigs 7 and 28 days) Blood test all gilts and sows annually, at least 3 weeks before breeding, for Brucellosis, Leptospirosis, and Pseudorabies Isolate all purchased breeding stock for at least 30 days before adding to herd
How To Profitably Increase Litter Size Page 2 March 1999 Treat for internal and external parasites as needed (using approved control methods--treat 2 weeks apart for internal parasites, treat 10 days apart for external parasites) Expose boars that have been purchased to breeding stock by fence-line contact and pen switching, allowing manure contact in the feed area (to help pigs build immunities to such viruses as SMEDI) D) Management before and during breeding season Breed gilts at approximately 5 to 8 months of age (preferably at their third heat period) Flush gilts by feeding 6 to 8 pounds daily for 14 days prior to breeding Double mate by breeding Boar A at beginning of heat, and 24 hours later to Boar B in commercial herd, and to same boar (Boar A) in purebred herd Record breeding dates in permanent file and record farrowing dates in pocket notebook During hot weather provide access to cooling devices (natural shade, sanitary hog wallows, or mist devices) from time of breeding to farrowing Reduce feed to 4 pounds of 15 percent protein (daily) 1 day after breeding. Continue this level until 3 weeks prior to farrowing E) Late gestation and farrowing Increase feed level (to approximately 5 to 6 pounds) during last 3 to 4 weeks before farrowing, depending on condition of the sow Ten to fourteen days before farrowing, deworm sows with Tramisol or Atgard. If threadworms are present use Thibenzole Bring sows to holding area 4 to 5 days before farrowing. Wash down with hose and, if necessary, treat for external parasites Three days before farrowing, wash and scrub thoroughly (especially underline), apply disinfectant, and place in clean farrowing stall Have necessary equipment and supplies available at farrowing time Be present at farrowing time and give needed assistance Keep a permanent record of litter size, weight at birth, and weight at 21 days F) Boar Management Test boars for Brucellosis, Leptospirosis, and Pseudorabies 30 to 60 days before breeding begins; vaccinate for Atrophic Rhinitis if it has not been done. On annual basis, vaccinate for Atrophic Rhinitis, Leptospirosis, and Erysipelas Feeding: Non-breeding seasons. Feed mature boars 3 to 4 pounds daily of balanced ration (14 to 15 percent protein) Breeding season. Mature boars10 days prior to the breeding season increase feed intake to 6 pounds feed, and continue this level during heavy service Young boars -feed approximately 6 pounds daily, or feed according to condition and development When hand mating, feed after boar services the sow Before breeding season: Cut tusks of mature boars at least 2 weeks before breeding Check feet and trim toenails if necessary 3 to 4 weeks before breeding season One week prior, breed mature boar to market gilt (to insure better fertility) Two to three weeks before season, breed young boar to a few market gilts (to insure better fertility). Assist boar during learning process Frequency of service Systems of mating: Hand mating -place female in lot with boar during cool part of day (early morning or late evening); constant mist sprays during summer months are helpful Pasture mating (boar and females together)-have shady areas, sanitary wallows, or mist sprays during summer. Rotate boars: one boar of group of boars one day and another group the next day
How To Profitably Increase Litter Size Page 3 March 1999 WAYS TO LOSE $ Fail to isolate newly purchased animals Subject sows and gilts to extreme high temperatures during breeding Overfeed sows, gilts, and boars Feed unbalanced rations Overwork boar Use contaminated lots Disregard disease and parasite control Run sows and gilts together Keep inadequate records Fail to vaccinate for Leptospirosis, Erysipelas, and Atrophic Rhinitis WAYS TO MAKE $ Select gilts from lines with large litter size records. Keep breeding animals cool and comfortable during breeding and gestation period Practice a sound cross-breeding program Grow gilts out so they are in medium flesh and vigorous condition Flush gilts two weeks before breeding Breed gilts at third heat period Use double mating breeding system Decrease energy intake following breeding Increase feed level the last third of gestation period Be present at farrowing time Table 1. ESTIMATED FEED COST OF PIGS AS INFLUENCED BY LITTER SIZE Number of Pigs per Litter Estimated Feed Cost 1 Per Live Pig at Birth When Sows/Boars Feed 2 Costs: .04/lb .06/lb .08/lb .10/lb .12/lb .14/lb 2 22.00 33.00 44.00 55.00 66.00 77.00 4 11.00 16.50 22.00 27.50 33.00 38.50 6 7.33 11.00 14.66 18.33 22.00 25.66 8 5.50 8.25 11.00 13.75 16.50 19.25 10 4.40 6.60 8.80 11.00 13.20 15.40 12 3.67 5.50 7.33 9.16 11.00 12.83 14 3.14 4.71 6.29 7.85 9.43 11.00 1) In dollars. 2) 2200 lb. feed per sow per year (including boar requirement); based on 2 litters per sow per year and 1 boar per 10 sows.
How To Profitably Increase Litter Size Page 4 March 1999 Table 2. ESTIMATED COST OF FEEDER PIGS TO FORTY POUNDS Number of Pigs per Litter Estimated Cost of 40 lb. Feeder Pig 1 When Sows/Boars Feed Cost is .10$/lb 2 and Overhead 3 Per Head is: $2 $4 $8 $12 2 66.00 68.00 72.00 76.00 4 38.50 40.50 44.50 48.50 6 29.33 31.33 35.33 39.33 8 24.75 26.75 30.75 34.75 10 22.00 24.00 28.00 32.00 12 20.16 22.16 26.16 30.16 14 18.85 20.85 24.85 28.85 1) 60 lb. of feed consumption per pig is estimated from weaning to 40 lb. 2) 2200 lb. per year. 3) Overhead includes facilities, veterinary costs, and labor. Table 3. Breeding and Farrowing Dates GESTATION TABLE Date bred Sow 114 days (date due) Date bred Sow 114 days (date due) Jan. 1 April 25 July 5 Oct. 27 Jan. 6 April 30 July 10 Nov. 1 Jan. 11 May 5 July 15 Nov. 6 Jan. 16 May 10 July 20 Nov. 11 Jan. 21 May 15 July 25 Nov. 16 Jan. 26 May 20 July 30 Nov. 21 Jan. 31 May 25 Aug. 4 Nov. 26 Feb. 5 May 30 Aug. 9 Nov. 31 Feb. 10 June 4 Aug. 14 Dec. 6 Feb. 15 June 9 Aug. 19 Dec. 11 Feb. 20 June 14 Aug. 24 Dec. 16 Feb. 25 June 19 Aug. 29 Dec. 21 Mar. 2 June 24 Sept. 3 Dec. 26 Mar. 7 June 29 Sept. 8 Dec. 31 May 12 July 4 Sept. 13 Jan. 5
How To Profitably Increase Litter Size Page 5 March 1999 Mar 17 July 9 Sept. 18 Jan. 10 Mar 22 July 14 Sept. 23 Jan. 15 Mar 27 July 19 Sept. 28 Jan. 20 April 1 July 24 Oct. 3 Jan. 25 April 6 July 29 Oct. 8 Jan. 30 April 11 Aug. 3 Oct. 13 Feb. 4 April 16 Aug. 8 Oct. 18 Feb. 9 April 21 Aug. 13 Oct. 23 Feb. 14 April 26 Aug. 18 Oct. 28 Feb. 19 May 1 Aug. 23 Nov. 2 Feb. 24 May 6 Aug. 28 Nov. 7 Mar. 1 May 11 Sept. 2 Nov. 12 Mar. 6 May 16 Sept. 7 Nov. 17 Mar. 11 May 21 Sept. 12 Nov. 22 Mar. 16 May 26 Sept 17 Nov. 27 Mar. 21 May 31 Sept. 22 Dec. 2 Mar. 26 June 5 Sept. 27 Dec. 7 Mar. 31 June 10 Oct. 2 Dec. 12 April 5 June 15 Oct. 7 Dec. 17 April 10 June 20 Oct. 12 Dec. 22 April 15 June 25 Oct. 17 Dec. 27 April 20 June 30 Oct. 22