Reproductive parameters of Bos taurus and Bos indicus bulls during different seasons in tropical conditions: focus on an alternative approach to testicular assessments using ultrasonography

• Published in: Animal reproduction science 2021-02, Vol.225, p.106668-106668, Article 106668
• Main Authors: Leite, Roberta Ferreira, de Agostini Losano, João Diego, de Souza Ramos Angrimani, Daniel, Sousa, Raphaela Gabrielle Brito, de Miranda Alves, Álvaro, Cavallin, Mônica Degraf, Kawai, Giulia Kiyomi Vechiato, Cortada, Carmen Neusa Martins, Zuge, Roberta Mara, Nichi, Marcilio
• Format: Article
• Language: English
• Subjects: Bovine; Heat stress; Sperm defects; Spermatozoa; Testicle; Ultrasonography
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2020.106668

The aim of the present study was to evaluate the reproductive status of Bos taurus and Bos indicus bulls during different seasons when bulls were in a tropical environment focusing on systematic assessment of the testes using B-mode ultrasonography and ImageJ software to evaluate the testicular parenchymal tissues. The experimental design is a 2 × 2 factorial arrangement, with breed (Bos Taurus – Simmental; Bos indicus - Nellore) and season (summer; winter) as factors. Testicular ultrasonic evaluation and conventional semen analysis were performed. The Simmental bulls had more major sperm defects than Nellore bulls in the summer (P = 0.0001). Additionally, Simmental bulls had a greater percentage of major sperm defects during the summer than winter months P = 0.045). Furthermore, Nellore bulls had a greater testicular parenchyma echogenicity, with a greater grayscale, (caudal parenchyma, P = 0.0155; cranial parenchyma, P = 0.001) and mediastinum grayscale than Simmental bulls (Nellore = 52.32 ± 03.60; Simmental = 35.72 ± 03.67; P = 0.003). Simmental bulls also had a greater testicular lesion area (P = 0.0147). Results indicated there was susceptibility to heat stress when Simmental bulls were maintained in tropical regions. The results of the present study indicate there is an association between results when there was use of conventional andrological evaluation procedures and results from ultrasonic analysis using ImageJ software that allows for earlier identification of tissue aberrations that could lead to impaired semen quality and fertility.