Linked Life Data

15956479

Source:http://linkedlifedata.com/resource/pubmed/id/15956479

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2005-6-15
pubmed:abstractText
In some production settings, beef bulls are mixed at the beginning of the finishing period to obtain homogeneous groups to facilitate finishing and to produce more homogeneous carcasses. Given the stress induced by mixing, we questioned whether this practice was profitable. Sixty-four young bulls were finished in groups of four over 8 mo. They were either mixed or unmixed and had either homogeneous vs. heterogeneous BW at the beginning of finishing. Behavioral traits (social behavior following mixing and general activities during the finishing period), stress measurements (cortisol concentration, adrenal weight, catecholamine-synthesizing enzyme activity, and pain sensitivity), and production traits (growth rate, homogeneity, feed efficiency, and carcass measurements) were evaluated. Bulls reacted to the mixing with increased frequency of social interactions (agonistic interactions: 17.9 in mixed vs. 1.2 in unmixed bulls, P < 0.001; sexual interactions: 9.6 vs. 1.7, P < 0.001; nonagonistic interactions: 5.25 vs. 3.1, P < 0.05). Agonistic and sexual interactions were more frequent between bulls of homogeneous BW (P < 0.05). Throughout the finishing period, the synchronization of activity tended to be lower between mixed bulls (P = 0.09). At slaughter, the activity of tyrosine hydroxylase, a catecholamine-synthesizing enzyme, was increased in mixed bulls (1.52 vs. 1.16 nmol.h(-1).mg(-1), P < 0.05), which may indicate chronic stress. No differences were noted in ADG or carcass traits among treatments. The variability of BW within groups increased in groups that were initially homogeneous, whereas it decreased in groups that were initially heterogeneous. In conclusion, mixing young beef bulls at the beginning of the finishing period did not have detrimental effects on health and production, but mixing induced stress, perhaps due to decreased cohesion within groups. Thus, we failed to confirm the proposed benefit of mixing bulls to homogenize their BW at the onset of finishing because BW homogeneity within groups was not maintained throughout the finishing period.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1525-3163
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
83
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1696-704
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Behavior, physiology, and performance of bulls mixed at the onset of finishing to form uniform body weight groups.
pubmed:affiliation
URH-ACS, INRA de Theix, 63122 Saint Genes Champanelles, France. l.mounier@vet-lyon.fr
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't