Animal and Veterinary Sciences 2017; 5(3): 45-51 http://www.sciencepublishinggroup.com/j/avs doi: 10.11648/j.avs.20170503.12 ISSN: 2328-5842 (Print); ISSN: 2328-5850 (Online) Influence of Seasonality on Buffalo Semen Sâmia Rubielle Silva de Castro 1, 3, * , Adriana Caroprezzo Morini 1 , Alanna do Socorro Lima da Silva 1 , Kedson Alessandri Lobo Neves 1, 2, 3 , Antônio Humberto Hamad Minervino 1, 2, 3 , Anderson Alvarenga de Moura Meneses 2, 3 , William Gomes Vale 1, 2, 3 1 Laboratory Animal Biotechnology, Institute of Biodiversity and Forests (IBEF), Federal University of Western Pará, Santarém, Brazil 2 Institute of Geosciences and Engineering (IEG), Federal University of Western Pará, Santarém, Brazil 3 Postgraduate Program in Society, Nature and Development (SND), Federal University of Western Pará, Santarém, Brazil Email address: samiarubielle@hotmail.com (S. R. S. de Castro) * Corresponding author To cite this article: Sâmia Rubielle Silva de Castro, Adriana Caroprezzo Morini, Alanna do Socorro Lima da Silva, Kedson Alessandri Lobo Neves, Antônio Humberto Hamad Minervino, Anderson Alvarenga de Moura Meneses, William Gomes Vale. Influence of Seasonality on Buffalo Semen. Animal and Veterinary Sciences. Vol. 5, No. 3, 2017, pp. 45-51. doi: 10.11648/j.avs.20170503.12 Received: March 21, 2017; Accepted: April 18, 2017; Published: June 23, 2017 Abstract: The present study was undertaken with the objective to compare the influence of seasonal temperature variations on parameters of ejaculates of Murrah buffalo bulls raised in the humid tropical Amazonian climate. Five buffaloes were selected from a batch of 12 adult bulls, pre-evaluated for clinical and andrological examination, and were used as semen donors, using as criterion the best ejaculate quality. The objective of the present study was, therefore, to test the hypothesis that season affects buffalo semen quality in tropical regions. The experimental period was divided into two phases: rainy season (RS), from February to May, and non rainy season (nRS), from August to November 2016. The ejaculates were collected twice a week (n=30) per bull, namely 10 ejaculates in the RS and 20 ejaculates in the nRS period, totaling (n=150) samples for analysis. The evaluations of the semen samples were performed with fresh semen, immediately after each collection. The immediate analyzes pertinent to the physical and morphological characteristics of the ejaculates showed that a significant statistical difference was observed for the parameters wave motion, motility, vigor, major defects, minor defects, total defects and plasma membrane integrity between the both periods (P<0.05). In the mesoregion of the Lower Amazon, a tropical region, the ideal period for experiments using buffalo ejaculates, are the months of the rainy season. For in this period a better quality without ejaculate of buffaloes was observed. Keywords: Amazon, Environment, Reproductive Parameters, Tropical Region, Season 1. Introduction In recent years the study of the influence of the environment on animal production has become important [1, 2, 3]. Buffaloes are homeothermic animals and, as such, are able to maintain their body temperature within a wide range, using some physiological and behavioural mechanisms that aid in thermoregulation. As buffaloes are raised in different climatic environments, such aspects provide this species the ability to adapt to diverse ecosystems. Ambient temperature is one of the climatic factors with the greatest influence on the physical environment in which the animal is found [4, 5]. Due the fact that sexual behaviour depends directly on the production of hormones, especially those produced by the pituitary-gonads and adrenal axis, the hormonal secretion of these endocrine glands can be suppressed when some stressor agent acts. Thus, males subjected to thermal stress have their sexual activity depressed, with less testosterone production, due to the production of stressors secreted by metabolism [1, 6, 7, 8, 9, 10]. In general, stress can be defined as any factor or change from the environment which interferes with homeostasis, which is a complex and dynamic system of equilibrium that governs the correct functioning of living organisms. Stress