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Kahwage PR, Esteves SN, Jacinto MAC, Junior WB, Pezzopane JRM, de Andrade Pantoja MH, Bosi C, Miguel MCV, Mahlmeister K, Garcia AR. High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds. Int J Biometeorol 2017; 61:1819-1829. [PMID: 28497170 DOI: 10.1007/s00484-017-1367-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 03/31/2017] [Accepted: 04/25/2017] [Indexed: 06/07/2023]
Abstract
This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1-animals maintained in the shade (11 to 12 h); period 2-animals exposed to sunlight (12 to 13 h); and period 3-animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased (P < 0.05), which matches a thermal discomfort situation. In period 3, the variables returned to baseline values and some values were lower than those in period 1. Semen quality and testicular parenchyma integrity suffered no negative effects with the thermal challenge. IRT ocular and IRT testicular were positively correlated (P < 0.05). It is concluded that MN and SIN rams had efficient thermolytic mechanisms that favor preserving gonadal functionality. The animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.
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Affiliation(s)
- Priscila Reis Kahwage
- Post graduate Program in Animal Science, Federal University of Pará (UFPA), Belem, PA, Brazil
| | - Sérgio Novita Esteves
- Embrapa Southeast Livestock (CPPSE), Brazilian Agricultural Research Corporation, Sao Carlos, SP, Brazil
| | | | - Waldomiro Barioni Junior
- Embrapa Southeast Livestock (CPPSE), Brazilian Agricultural Research Corporation, Sao Carlos, SP, Brazil
| | | | | | - Cristian Bosi
- Embrapa Southeast Livestock (CPPSE), Brazilian Agricultural Research Corporation, Sao Carlos, SP, Brazil
| | | | - Kaue Mahlmeister
- Embrapa Southeast Livestock (CPPSE), Brazilian Agricultural Research Corporation, Sao Carlos, SP, Brazil
| | - Alexandre Rossetto Garcia
- Embrapa Southeast Livestock (CPPSE), Brazilian Agricultural Research Corporation, Sao Carlos, SP, Brazil.
- Laboratory of Biotechnology of Animal Reproduction, Brazilian Agricultural Research Corporation/Embrapa Southeast Livestock (CPPSE), Rod. Washington Luiz, km 234, Fazenda Canchim, Sao Carlos, SP, 13560-970, Brazil.
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