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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #319054
Title: Use of indoor boars as models for understanding seasonal infertility: Preliminary data

Author
item DILLARD, D - Mississippi State University
item CRENSHAW, M - Mississippi State University
item WILLARD, SCOTT - Mississippi State University
item RYAN, P - Mississippi State University
item FEUGANG, J - Mississippi State University

Submitted to: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/27/2014
Publication Date: 7/17/2014
Citation: Dillard, D.S., Crenshaw, M.A., Willard, S.T., Ryan, P.L., Feugang, J.M. 2014. Use of indoor boars as models for understanding seasonal infertility: Preliminary data. Society for the Study of Reproduction Annual Meeting. P. 573.

Interpretive Summary: Variations of environmental factors such as temperature, solar radiation, daylight length, and humidity throughout the calendar year are usually referred to as seasonal variations, and have significant impacts on animal reproduction. This phenomenon often appears during hot summer months and early fall and has been termed seasonal infertility. Reproductive impacts of seasonal variations on outdoor animals are considerable, especially in swine, and the impact on semen production and quality for artificial insemination could significantly jeopardize the entire marketing chain, as the use of cryopreserved semen remains limited in the swine industry. This study was conducted to evaluate the potential impacts of external temperature and relative humidity (RH) variations on semen production of boars maintained in thermo-regulated barns (indoor housing). We observed that boars housed indoor still experience the impacts of environmental temperature and RH variations despite the thermoregulation of barns. A study of boar fertility performance in such barns could help our understanding of semen subfertility issues. Further studies are needed to investigate the potential effects of day-by-day environmental variations on sperm production and quality, and to compare these effects across seasons.

Technical Abstract: This study was conducted to evaluate the potential impacts of external temperature and relative humidity (RH) variations on semen production of boars maintained in thermo-regulated barns (indoor housing). Data were collected from a local commercial hog operation. Temperature and relative humidity (RH) sensor devices (HOBO data loggers) were placed both outside and inside the barn, in the vicinity but out of reach of boars. Both sensors were calibrated to log temperature and RH at 30 minutes intervals, from November 2013 to February 2014. Recorded data were uploaded every week to a computer for data processing. External temperature profiles were compared to those obtained from the National Weather Service to validate our recording system. We used a Digital Infrared Thermo-Imaging (DITI) camera to measure the scrotal surface temperature gradient to evaluate the impacts of seasonal variations on testicular functions. Semen was harvested twice a month from ten fertile boars that were randomly selected and production outputs and sperm motility characteristics were evaluated. DITI images were taken at semen collection and images were analyzed. Data were analyzed using the GLM procedure (SPSS) and P<0.05 indicated significant differences. Results indicated that external temperature profiles mirrored the National Weather Service reports, which confirmed the accuracy of our recording system. There were high fluctuations of outside temperatures and RH throughout days and months, with January and February being the coldest months. Inside temperatures were constant throughout the entire experimental period, despite external temperature variations. RH within the barn highly fluctuated and followed the pattern of the outside values. Temperature variations did not affect semen production outputs, although the total sperm count per ejaculate tended to decrease during the coldest months. The proportions of motile sperm and velocity characteristics were significantly affected, with the lowest proportions of fast and progressive spermatozoa found during the coldest month. In conclusion, indoor housed boars still experience the impacts of environmental temperature and RH variations despite the thermoregulation of barns. The study of boar fertility performance in such barns could help our understanding of semen subfertility issues. Further studies are needed to investigate the potential effects of day-by-day environmental variations on sperm production and quality, and to compare these effects across seasons.