title: The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction.
abstract: The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1%), summer (57.6%), and autumn (64.5%) showed difference compared to winter (73.0%; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls.
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Silvio Renato Oliveira
authors.initials: SR
authors.lastname: Menegassi
authors.affiliation: Centre for Studies and Research in Agribusiness - CEPAN, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, 91540-000, Porto Alegre, RS, Brazil. gabrielribaspereira@gmail.com.
authors.forename: Gabriel Ribas
authors.initials: GR
authors.lastname: Pereira
authors.affiliation: Centre for Studies and Research in Agribusiness - CEPAN, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Eduardo Antunes
authors.initials: EA
authors.lastname: Dias
authors.affiliation: College of Veterinary Medicine, University of Northern Paraná, 86041-120, Londrina, PR, Brazil.
authors.forename: Celso
authors.initials: C
authors.lastname: Koetz
authors.affiliation: College of Veterinary Medicine, University of Northern Paraná, 86041-120, Londrina, PR, Brazil.
authors.forename: Flávio Guiselli
authors.initials: FG
authors.lastname: Lopes
authors.affiliation: Animal Production Department, FEPAGRO, 90130-060, Porto Alegre, RS, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Bremm
authors.affiliation: University of Brasília and INCT Pecuária, 70910-900, Brasília, DF, Brazil.
authors.forename: Concepta
authors.initials: C
authors.lastname: Pimentel
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Rubia Branco
authors.initials: RB
authors.lastname: Lopes
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Marcela Kuczynski
authors.initials: MK
authors.lastname: da Rocha
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Helena Robattini
authors.initials: HR
authors.lastname: Carvalho
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, 91540-000, Porto Alegre, RS, Brazil.
authors.forename: Júlio Otavio Jardim
authors.initials: JO
authors.lastname: Barcellos
mesh_terms: D000818:Animals; D001831:Body Temperature; D002417:Cattle / Q000502:physiology*; D006813:Humidity; D007259:Infrared Rays; D008297:Male; D012098:Reproduction; D012621:Seasons; D013081:Sperm Motility; D013091:Spermatogenesis; D013696:Temperature; D013737:Testis / Q000502:physiology; D013817:Thermography
keywords: Bulls; Environmental changes; Infrared thermography; Semen quality