title: Effects of ambient air temperature, humidity, and wind speed on seminal traits in Braford and Nellore bulls at the Brazilian Pantanal.
abstract: The aim of this study was to evaluate the bioclimatic thermal stress assessed by Equivalent Temperature Index (ETI) and Temperature Humidity Index (THI) on Braford and Nellore bulls sperm quality during the reproductive seasons at the tropical region in the Brazilian Pantanal. We used 20 bulls aged approximately 24 months at the beginning of the study. Five ejaculates per animal were collected using an electroejaculator. Temperature, air humidity, and wind speed data were collected every hour from the automatic weather station at the National Institute of Meteorology. Infrared thermography images data were collected to assess the testicular temperature gradient in each animal. Data were analyzed with ANOVA using MIXED procedure of SAS and means were compared using Tukey's HSD test. The THI and ETI at 12 days (epididymal transit) were higher in January (89.7 and 28.5, respectively) and February (90.0 and 29.0, respectively) compared to other months (P < 0.01). Total seminal defects differ only in Bradford bulls between the months of November and February. Nellore bulls had lower major defects (MaD) and total defects (TD) compared to Braford. Nellore bulls showed correlation between minor defects (MiD) and THI for 30 days (0.90) and 18 days (0.88; P < 0.05). Braford bulls showed correlation for MaD (0.89) in ETI for 12 days (P < 0.05). Infrared thermography showed no difference between animals. Reproductive response to environmental changes is a consequence of Nellore and Braford adaptation to climate stress conditions. Both THI and ETI environmental indexes can be used to evaluate the morphological changes in the seminal parameters in Nellore or Braford bulls; however, more experiments should be performed focusing on larger sample numbers and also in reproductive assessment during the consecutive years to assess fertility potential.
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, Brazil.
authors.forename: Silvio Renato Oliveira
authors.initials: SR
authors.lastname: Menegassi
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, Brazil. gabrielribaspereira@gmail.com.
authors.forename: Gabriel Ribas
authors.initials: GR
authors.lastname: Pereira
authors.affiliation: Animal Production Department, FEPAGRO, Porto Alegre, RS, 90130-060, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Bremm
authors.affiliation: College of Veterinary Medicine, University of Northern Paraná, Londrina, PR, 86041-120, Brazil.
authors.forename: Celso
authors.initials: C
authors.lastname: Koetz
authors.affiliation: College of Veterinary Medicine, University of Northern Paraná, Londrina, PR, 86041-120, Brazil.
authors.forename: Flávio Guiselli
authors.initials: FG
authors.lastname: Lopes
authors.affiliation: College of Veterinary Medicine, University of Northern Paraná, Londrina, PR, 86041-120, Brazil.
authors.forename: Eduardo Custódio
authors.initials: EC
authors.lastname: Fiorentini
authors.affiliation: INCT Pecuária, University of Brasília, Brasília, DF, 70910-900, Brazil.
authors.forename: Concepta
authors.initials: C
authors.lastname: McManus
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, Brazil.
authors.forename: Eduardo Antunes
authors.initials: EA
authors.lastname: Dias
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, 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, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, Brazil.
authors.forename: Rubia Branco
authors.initials: RB
authors.lastname: Lopes
authors.affiliation: Department of Animal Science, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, n.: 7.712, Porto Alegre, RS, 91540-000, Brazil.
authors.forename: Júlio Otávio Jardim
authors.initials: JO
authors.lastname: Barcellos
mesh_terms: D000818:Animals; D001938:Brazil; D002417:Cattle; D006813:Humidity; D008297:Male; D012621:Seasons; D013094:Spermatozoa; D013312:Stress, Physiological; D013696:Temperature; D014919:Wind
keywords: Adaptability; Bulls; Semen parameters; Thermal indexes; Tropical region