|Chase, Chadwick - Chad|
Submitted to: Revista Cientifica-Universidad Del Zulia Faculatad De Ciencia Veterinarias Division De Investigacion
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2005
Publication Date: 7/29/2005
Citation: Landaeto-Hernandez, A.J., Chenoweth, P.J., Randles, R., Littell, R., Rae, O.D., Chase, C.C. 2005.Identifying the social dominance order in a mixed breed herd. a practical methodology. Revista Cientifica-Universidad Del Zulia Faculatad De Ciencia Veterinarias Division De Investigacion.15(2):148
Interpretive Summary: There is increased interest in understanding the behavioral patterns of domestic animals. Social organization within herds can influence animal productivity including grazing activity and weight gain, feed intake, milk yield, estrus expression, and performance in confinement. Knowledge of social organization within herds is important for the design of optimal management systems as well as in the design of research experiments. Lack of a practical and accurate methodology to assess social behavior in cattle has limited the usefulness. The intent of this study was to develop a practical methodology to estimate dominance values and subsequent social categorization in cattle. Two mixed breed groups of cows (5 Angus, 5 Brahman, and 5 Senepol cows in each group) were observed twice daily during concentrate feeding for 45 days. Agonistic behavior, i.e., a winner and loser, of each encounter was recorded. From this information three methods of assigning dominance values were compared, and Method III - the proportion of individuals beaten to total herdmates appeared to be the most practical and accurate method for estimating dominance value and subsequent allotment of cows into a social dominance order. In contrast the other two methods appeared to overestimate or underestimate the social status of individual animals. Use of total herdmates in the proportion for Method III seemed to be important particularly for subsequent within herd social ranking.
Technical Abstract: The major objective of this study was to identify a simple and accurate method of assessing differences in female social status. Three methods of estimating dominance value (DV) were compared in beef cows of three breed-types; Angus (A; n=10), Brahman (B; n=10), and Senepol (S; n=10). Cows were equally assigned to two groups of fifteen each, allocated into separate pastures and containing equal number of animals per breed. Agonistic interactions were recorded for 45 d of study, in two 1 h periods during concentrate feeding using the method of competitive orders winner/ looser. Methods of estimating DV included: I) Ratio between individuals dominated and total encountered, II) Ratio between encounters won to total encounters, III) Proportion individuals dominated to total herdmates. Due to the different level of interactivity evidenced among animals as well as between and within social orders, method III with subsequent arc-sin transformation was considered as the most practical and accurate method for estimating DV and subsequent allocation of cows into a social dominance order.