Download - WILD PIG REPRODUCTION IN LOUISIANA …… JUST THE FACTS

WILD PIG REPRODUCTION IN LOUISIANA …… JUST THE FACTS

Kim Marie Tolson, ULM James M. LaCour, LDWF

Misconceptions in the Media


“Adult sows can produce three litters a year.”


“Adult sows can produce three litters a year.”

“one female can have 300 piglets in two years”

BIOLOGY OF WILD PIGS•Habitat generalists• Low natural mortality•Opportunistic omnivores•High reproductive potential

Wild Pig Breeding Biology• Early reproductive maturity• Gestation period ~114 days– 3 months, 3 weeks, 3 days– potential multiple litters/yr

• Capability to produce large litters

HIGH REPRODUCTIVE POTENTIAL!!

OBJECTIVES

• Characterize the breeding biology of wild pigs in Louisiana– Determine average litter size– Calculate reproductive efficiency– Determine peak breeding dates– Compare data with other populations of feral hogs

METHODS

• Collection May 2010 to June 2011• Reproductive tracts removed: ovaries & uterus•

- Collection Date- Location (Parish)- Weight- Notes- Tracts frozen

METHODS

• OVARIES– Preserved in 10% buffered formalin– Sliced in 1-2 mm sections– Presence/number of follicles or corpora lutea (CL)

Ovary with follicles Ovary with CLPhotos courtesy Meg O’Boyle

METHODS

• UTERI– Number and gender of fetuses– Crown-rump measurements (avg. for litter)– Extrapolate breeding and farrowing dates

(Henry 1968)

RESULTS

• 87 Reproductive Tracts– 80 Adults + 7 Sub-adults– 47 lb. sow with follicular development

RESULTS

• 35 Pregnant 43.75%• 40 Developing follicles 50.00%• 2 CL in ovaries 2.50%• 3 No repro activity 3.75% 80 Adult sows

(77/80 showed repro activity in ovaries)

RESULTS

CL Fetuses RE*__Sum 229 176 76.85%----------------------------------------------------------------Mean 6.54 5.03----------------------------------------------------------------Range (4-10) (2-10)----------------------------------------------------------------*RE = (# fetuses / # CL) x 100

COMPARISON OF LITTER SIZE_____________________________________________________________________________________________Location n Mean # of fetuses (range) Reference_____________

Louisiana 35 5.03 (2-10) Tolson and LaCour (2013) Georgia 17 6.20 (?-9) Hagen and Kephart (1980) (penned) Georgia 35 5.89 (3-11) Jolley (2007) (free ranging) South Carolina 8 7.40 (5-12) Sweeney et al. (1979) Tennessee 20 4.65 Henry (1968) Texas 64 5.40 (2-11) Delgado-Acevedo et al. (2010) (southern and central counties) Texas 21 6.30 Taylor et al. (1998) -South Texas Plains (western) Texas 18 5.60 Taylor et al. (1998) -Gulf Coast Prairie (eastern) New Zealand 291 6.20 (1-11) Dzieciolowski et al. (1992) Spain 52 3.58 (1-7) Fernandez-Llario and Mateos-

Quesada (1998)__________

Conception Dates

Farrowing Dates

Breeding Biology of Wild Pigs in Louisiana

• Average litter size is 5-6• Conception and farrowing occurs year round• Two peaks in conception:– Broad peak from Sept. through Dec.– Narrow peak in Feb. – Mar.

• Results not unexpected – parallels other hog populations across the south.

Reproductive Potential

• Age of Reproductive Maturity – around 6 months– 47 pounds!

• Number of Litters per Year– Commonly reported = 2/12 mos.– Actually = 2/15-18 mos.

• Number of offspring per Litter– Average = 5 to 6

Wildpiginfo.msstate.edu

www.flickr.com

Reproductive PotentialComparison of Large Mammals

White-tail Deer Wild PigReproductive maturity

Avg. # offspring

Frequency of breeding


White-tail Deer Wild PigReproductive 18 mo. ~ 6 mo. maturity

Avg. # offspring




Avg. # offspring 1.5 5-6




Avg. # offspring 1.5 5-6

Frequency of breeding 1/12 mo. 1/8-9 mo.

REPRODUCTIVE FACTS

• Both sexes can live 10-14 yrs (avg. is 4-8 yrs)• No reproductive senescence has been noted• Litters can be sired by more than 1 male• Males produce viable sperm year round• Synchronous estrous by females in a sounder

REPRODUCTIVE FACTS

• FEMALES:– Lactation may inhibit estrous for up to 2 months– May experience anestrous period in hot/dry mos.– Anestrous also reported in years of mast failure– Food resources can influence reproduction

CONCLUSIONS

• Wild pigs may not be as prolific as they are often made out to be in the media

CONCLUSIONS

• Wild pigs may not be as prolific as they are often made out to be in the media

• BUT, their reproductive potential is greater than native large mammals

ACKNOWLEDGEMENTS

• Dr. James LaCour• Meghan O’Boyle• ULM Biology graduate students• USDA/APHIS-Wildlife Services personnel• LDWF personnel• USFWS personnel at Lake Ophelia NWR and

Upper Ouachita NWR• Barksdale AFB personnel

QUESTIONS?

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