Author/Authors :
Kazemi-Bonchenari، M نويسنده Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Arak, Iran , , Javanmard، M. R نويسنده Department of Veterinary and Food Hygiene, University of Scientific-Applied, Arak, Iran , , Mahjoubi، E نويسنده Department of Animal Science, Zanjan University, Zanjan, Iran , , Afshar، S نويسنده Institute of Scientific-Applied Higher Education of Jihad-e-Agriculture- Agricultural Research, Education and Extension Organization, Tehran, Iran ,
Abstract :
Two separate experiments were conducted using a total of 130 male lambs to find feed efficiencies in different weights (experiment 1: N=50) and also the effects of castration (experiment 2: N=80) on performance of Iranian fat-tailed Lori-Bakhtiari sheep. In the first experiment 50 male lambs averaging BW 27.3 kg were fattened based on the same basal diets. Performance data was recorded throughout the five consecutive months (M1-M5) and the experiment lasted 150 d. The optimal feed efficiency was identified based on performance data comparisons during the five-month fattening period. To investigate the effects of castration on performance, 80 male were allocated in two different treatments (T1=40 intact and T2=40 castrated animals). The second experiment lasted 110 d. The results in experiment 1 showed that the greatest average daily gain (ADG) was achieved in M4 and the best value for feed conversion ratio (FCR) was attained in M1. The greatest intake value was observed in M5 of the experiment which reduced efficiency in this group compared to the other groups. Based on the first experiment, slaughter weight of approximately 58 kg may be recommendable as an optimal weight in Lori-Bakhtiari sheep. The second’s experiment results showed that FCR, ADG and intake were not different between castrated and intact animals. Because castration is time and labor consuming, and no improvement was observed in castrated animals compared to intact ones, castration may not be recommendable to increase profit in Lori-Bakhtiari sheep under current production systems.
