Document Type: Original Article


1 M.Sc. Student of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran

2 Professor, Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran


Castration of male animal's leads to a reduction in aggressive behavior, which animals will avoid wasting energy resulting to economic production of the animal, grows. It also reduces damage and bruising animals and increases normed meat producing at slaughter. In this study, 20 lambs Ghezel breed in four age groups, group 1: one month (n = 4), group 2: two months (n = 4) Group 3: three months (n = 4), Group 4: four months (n = 4), were selected and by the surgical procedure were castrated.  For comparing the effects of castration on fattening capacity and frequency of sexual behaviors, group 5: one month (n=4) was used as a control group. The GLM procedure of SAS in unbalanced design was used. Five groups of lambs were fed with a same diet of fattening for 270 day. Lambs weighing was done after 12 hours of starvation every month. A significant difference was observed between control group and other castrated groups (P<0.0001). The control group lambs showed a higher final average weight (46.125 kg) than the other castrated groups, group one: (41.6071 kg), group tow: (41.205 kg), group three (40.2823 kg) and group four (40.962 kg). Daily average gain for all groups was similar (Group 1 (133.024 g), Group 2 (120.307 g), Group 3 (113.48 g), Group 4 (113.154 g) and control group (152.068 g)) which was not a significant difference between castrated groups with control.  Body condition score at the end of period were measured for all groups and no significant difference was observed. Each of sexual behavior decreased significantly between the castrated and control group. The results showed that castration depressed aggression and reproductive behavior of animals. Weight of castrated group was lower than the control, in which the lamb that had been castrated at younger ages due to the low stress and get away from castration were better at slaughter time.


1.Davari,Fatemeh;Khazali,Homyoun;Rokni,Hasan;Fathehi,Zahra;1391.Iran.Endocrine grand's and metabolism magazine, medical science and health-therapeutic-services college of behest martyr; fourteenth course,number1,p81-87
2. Zamini, M, J.1388; Reproduction physiology; second edition, Hag Sheena's Publications.
3. Shahmoradi, M; Ghorbani.Gh; zoranol plant on fatten ability and corpse characteristics of hazel breed male and castrated lambs. Agricultural science of Tehran University.number 4.volume 27
4. Kiyma z, Adams T E, Hess B W, Riley M L, Murdoch W J,and Moss G E.2000. Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH. American Society of Animal Science.
5. Haddad S G, Husein M Q and Sweidan R W. (2006). Effects of castration on growth performance and carcass characteristics of Awassi lambs fed high concentrate diet.Small Ruminant Research, 65: 149-153.
6. Huxsoll C C, Price E O and Adams T E. (1998). Testis function, carcass traits, and aggressive behavior of beef bulls actively immunized against gonadotropin-releasing hormone.Journal of Animal Science, 76:1760-1766.
7. Adams T E, Daley C A, Adams B M and Sakurai H. (1993). Testis function and feedlot performance of bulls actively immunized against gonadotropin releasing hormone: Effect of implants containing progesterone and estradiol benzoate. Journal of Animal Science, 71: 811-817.
8. Cook R B , Popp J D, Kastelic J P, Robbins S and Harland R. (2000). The effects of active immunization against gnRH on testicular development, feedlot performance, and carcass characteristics of beef bulls. Journal of Animal Science, 78(11): 2778-2783
9. Ian G. Colditz, David R. Paull, Caroline Lee.2012. Social transmission of physiological and behavioural responses to castration in suckling Merino lambs. Applied AnimalBehaviour Science 136:136– 145
10. Brown B W, Mattner P E, Carroll P A, Holland E J, Paull D R, Hoskinson R M, and Rigby R D G. 1994. Immunization of sheep against GnRH early in life: Effects on reproductive function and hormones in rams. J. Reprod. Fertil. 101:15–21
11. Daley D A, Adams T E, Daley C A, Patton W R, and Evans J L.1995. Effect of immunocastration on growth, carcass characteristics and reproductive development in ram lambs. Sheep Goat Res. J. 11:31–34.
12. Schanbacher B D, Crouse J D , and Ferrell C L. 1980. Testosterone influences on growth, performance, carcass characteristics and composition of young market lambs. J. Anim. Sci. 51:685–691.
13.Baker A M,Gonyou H W.1986.Effects of zeranol and late castration on sexual, agontistic and handling behavior in male feedlot cattle, J.Anim. Sci.62:1224.
14.Calkins C R, Calton D C, Berg J J, Kinder J E.1986.Growth carcass and palatability traits of intact males and steers implanted with zeranol or estradiol early and throughout life .J. Anim .Sci.62:625.
15.Field R A, Maiorano G, Hinds F C, Murdoch W J and Riley M L.1990. Bone ossification and carcass characteristics of wether given sillastic implants containing estradiol. Anim.Sci.68:663.
16. Grant C.2004. Behavioural responses of lambs to common painful husbandry procedures. Appl. Anim. Behav. Sci. 87, 255–273. 

17. Kent J E, Molony V, Graham M J.1998. Comparison of methods for the reduction of acute pain produced by rubber ring castration or tail docking of week-old lambs. Vet. J. 155, 39–51.
18. Kent J E, Molony V, Robertson I S.1995. Comparison of the Burdizzoand rubber ring methods for castrating and tail docking lambs. Vet.Rec. 136, 192–196.
19. Xu R, Wang Q, Yan M, Hernandez M, Gong C, Boon WC et al. Orexin-A augments voltage- gated
Ca2+ currents and synergistically increases growth hormone (GH) secretion with GH- releasing hormone in primary cultured ovine somatotropes. Endocrinology 2002; 143: 4609-19.
20.Wiggins J P, willson LL, Rothenbacher H and Davis S L.1976. Effects of diethyl stibestrol ,zeranol and sex on live blood metabolite ,carcass and endocrine characteristics of lambs. J.Anim.Sci 43:518
21. .Field R A, snowder G D, MaioranoG,Mccormick R J and Riley M L.1993. Growth and slaughter characteristics of ram and wether lambs implanted with zeranol. J.Anim.Sci.71:631.
22. Hinch G N. 1980. Handling strategies for entire and castrated male cattle. In: M.WodzickaTomaszewska and Lynch J J (Editors), Reviews in Rural Sciences (4): Behaviour in relation to Reproduction, Manage-ment and Welfare of Farm Animals. University of New England, Australia, pp. 157-160.
23. Grizzle T B, Esbenshade K L, and Johnson B H. 1987. Active immunization of boars against gonadotropin releasing hor-mone. I. Effects on reproductive parameters. Theriogenology27:571
24. Fahmy M H, Sairam M R, Proulx J G, Petit H V, Jiang L G, and Dufour J J. (1999).Effect of active immunization against luteinizing hormone on carcass and meat quality of Romanov lambs.Small Ruminant Research, 34,87-96.
25. Jago J G, Cox N R, Bass J J and Matthews L R.١٩٩٧ . The effect of prepubertal immunization against gonadotropin-releasing hormone on the development of sexual and social behavior of bulls.J .Anim.Sci: