Journal of Environmental Biology m November, 2008 m ' Triveni Enterprises, Lucknow (India) J. Environ. Biol. ISSN : 0254-8704 29(6), 877 -880 (2008) http : //www.geocities.com/j_environ_biol/ j_environ_biol@yahoo.com Effect of shearing and environmental conditions on physiological mechanisms in ewes G. Piccione* 1 , L. Lutri 2 , S. Casella 1 , V. Ferrantelli 3 and P. Pennisi 4 1 Dipartimento di Scienze Sperimentali e Biotecnologie Applicate - Facolta di Medicina Veterinaria - Universit di Messina - 98168, Messina - Italy 2 Istituto Sperimentale Zootecnico per la Sicilia, Palermo - 90100, Italy 3 Istituto Zooprofilattico Sperimentale della Sicilia, Palermo - 90100, Italy 4 Dipartimento di Scienze Agronomiche, Agrochimiche e delle Produzioni Animali. Sezione di Scienze delle Produzioni Animali. Universit degli Studi di Catania - 95100, Italy (Received: June 08, 2007; Revised received: September 18, 2007; Accepted: October 13, 2007) Abstract: The aim of this study was to establish the influence of shearing in dairy sheep during summer season. Several physiological and haematological parameters, which are closely related to thermoregulatory potential, have been investigated with the purpose to assess shearing influence on thermoregulation. Forty dairy sheep, clinically healthy and well-fed, were used. They were divided into two groups of 20 subjects each. Twenty sheep were let unshorn as a control group (Group A), and twenty sheep were shorn (Group B). On each subject of group A and Group B, rectal temperature, respiration and heart rates were recorded and blood samples were collected in order to asses the following parameters: red blood cells, white blood cells, platelets, haematocrit and haemoglobin. All measurements taken on day 0 (before shearing), were repeated after 1, 15, 30, 45 and 60 days after shearing. The statistical analysis, the ANOVA followed by the Bonferronis test, showed statistical differences between two groups for rectal temperature (F (1,90) =5.57, p<0.0001), respiratory rate (F (1,90) =18.40, p<0.0001) and white blood cells (F (1,190) =7.61, p<0.0001). These results suggest that the shearing induce adaptative responses in the organism. Key words: Fleece, Shearing, Physiological and Haematological parameters, Ewes PDF of full length paper is available with author (*giuseppe.piccione@unime.it) Introduction Studies of shorn and unshorn sheep, exposed to extreme environmental conditions, have long demonstrated the importance of the fleece for the maintenance of homeothermy (MacFarlane, 1968; Whittow, 1971). Also in a climatically mild atmosphere, the shearing induces in animals adaptive thermogenetics modifications (Caola et al., 1998). It is well known that to maintain body temperature constant, an animal has to satisfy the condition of stationary equilibrium, in which the metabolic production of heat is equal to its loss. The breadth of the thermoneutral zone depends on age, species and breed (Yousef, 1987). In sheep thermal regulation is influenced, among other factors, by characteristics of their fleeces. The sheep fleece is a natural thermoregulatory structure that is related to breed, age, sex and environmental conditions like temperature, relative humidity and wind (Sleiman, 1995; Hafez et al ., 1956; Moule, 1954). The fleece represents a compact insulating layer protecting the animal against both hot and cold (Bettini, 1988; Hammel, 1955). Many studies have been carried out to assess the influence of shearing and the type of shelter on homeostatic balance of sheep (Pennisi et al., 2004; Piccione et al ., 2003a; Piccione et al ., 2003b). The effects of shearing on productive performances in wool and meat breed have been reported by several researchers. Shearing pregnant ewes at mid or late pregnancy resulted in an increase in lamb birth weight (Kenyon et al., 2002; Morris et al ., 1997). On the contrary, the literature provides only little information about effects of shearing on physiological and productive parameters in dairy sheep. On the base of such considerations with the aim of evaluating the role of the fleece in the maintenance of thermal equilibrium during summer season in dairy sheep, we have studied the course of following physiological and haematological parameters: rectal temperature, respiratory and heart rates, red blood cells, white blood cells, platelets, haematocrit and haemoglobin. Materials and Methods The trial was carried out in a farm located in Sicily (38 o 7 N; 13 o 22 E) at an altitude of 300 metres above sea level. Environmental temperature peacked at 33 o C and relative humidity levels, with mean value of 45%, showed an inverse relationship to ambient temperature. The study started in June and ended in September and it was carried out on dairy sheep. Forty two-years-old, clinically healthy and well-fed Valle del Belice ewes were used in the experiment. As concerning feeding conditions, groups A and B were fed daily on hay (2 kg), wheat straw (1 kg), wheat concentrate (0.5 kg) and water ad libitum.