The objective of this study was to evaluate muscle composition and physical-chemical characteristics of 20 intact and castrated crossbred Ideal male lambs exposed to either a short photoperiod (SP) of 12 h or to a long photoperiod (LP) of 18 h. Animals were randomly assigned to four treatments (T) in a 2 x 2 factorial arrangement with five repetitions as follows: intact lambs exposed to a SP; castrated lambs exposed to a SP; intact lambs exposed to a LP or castrated lambs exposed to a LP. Animals were maintained in individual pens until they reached 37 kg of body weight. Meat quality was determined in meat samples from the blade and from the Longissimus lumborum muscle (loin). The lowest contents of moisture and the greatest contents of fat in both the blade and loin were observed on the meat of castrated lambs. The LP significantly affected the contents of fat and protein of the loin. The water-holding capacity of the loin was lowest when animals were exposed to a LP while no significant differences were observed for water-biding capacity and cooking losses. Meat from intact lambs had significantly higher shear force (SF) than from that of castrated lambs. In addition, exposition to a LP also significantly increased the SF compared to SP exposition.
castration; lamb; meat quality; photoperiod
