The objective was to evaluate diluents and transport systems on semen quality frozen by CASA in Nellore bulls. Five semen collections of six bulls, diluted with the TRISand BotuBOV®, were transported out on two types of BotuBOX® and BotuFLEX® systems; frozen and analyzed by CASA. TM was higher (p <0.05) in the association of BotuBOV® + BotuFLEX® (47.3%) when compared to TRIS + BotuBOX® (9%). The PM was higher (p <0.05) BotuBOV® + BotuFLEX® (37%) when compared to TRIS + BotuBOX® (5.9%). The same for VSL, BCF and RAP, which were higher (p <0.05) in BotuBOV® + BotuFLEX® (65.1μm/s, 30Hz, 44.5%, respectively) when compared to semen in the TRIS + BotuBOX® (47.6μm/s, 21.5Hz, 6.9%, respectively). It is concluded that BotuBOV® in association with the refrigerated system of semen BotuFLEX® was considered by CASA to be the best association when referring to sperm kinetics for cryopreservation of bovine semen.

RESUMOObjetivou-se estudar na pré-estação de monta e estação de monta a termorregulação testicular com termografia digital por infravermelho, a qualidade do sêmen e a morfometria testicular de touros jovens Nelore, criados extensivamente. Foram utilizados 20 touros Nelore, sendo realizadas, duas coletas de dados antes e duas durante a estação de monta, os procedimentos: coleta e análise de sêmen, mensuração da morfometria testicular e exames de termografia de infravermelho do escroto. Os dados foram submetidos à análise de variância, e comparadas pelo teste de Tukey a 5%. Não houve diferença (P>0,05) entre as estações para as características do sêmen. Houve diferença (P<0,05) entre estações para peso corporal e perímetro escrotal, ambos superiores no verão. As temperaturas do escroto não diferiram (P>0,05) entre estações. Conclui-se que os animais produziram sêmen de qualidade satisfatória com termorregulação testicular mostrando faixas decrescentes de temperatura do cordão espermático em relação ao testículo e caudas do epidídimo. Palavras-chave: espermatogênese; estações do ano; termograma escrotal; touro zebu. INFRARED THERMOGRAPHY OF SCROTUM, SPERMOGRAM AND TESTIS MORPHOMETRY IN NELLORE BULLS BEFORE AND DURING BREEDING SEASON ABSTRACTThe aim of this study was to study the testicular thermoregulation with infrared digital thermography, the semen quality and the testicular morphometry of young Nelore bulls, which were extensively raised. Twenty Nelore bulls were used, two collections of data were collected before and two during the breeding season, the procedures were: collection and analysis of semen, measurement of testicular morphometry and infrared scrotal thermography. The data were submitted to analysis of variance, and compared by the Tukey test at 5%. There was no difference (P> 0.05) between the seasons for semen characteristics. There was a difference (P <0.05) between seasons for body weight and scrotal perimeter, both higher in summer. Scrotal temperatures did not differ (P> 0.05) between seasons. It was concluded that the animals produced semen of satisfactory quality with testicular thermoregulation showing decreasing ranges of temperature of the spermatic cord in relation to the testis and tails of the epididymis. Keywords: spermatogenesis; seasons of the year; scrotal thermograph; bull zebu. INTRODUÇÃORevisando a literatura sobre reprodução de bovinos nos trópicos, Galina e Arthur (1991) abordaram a influência das estações do ano nas características quantitativas e qualitativas do sêmen, relatando que a baixa qualidade do sêmen em alguns animais pode ocorrer devido ao desconforto destes perante temperaturas elevadas.