Effects of repeated jugular puncture on plasma cortisol concentrations in loose-housed dairy cows.

摘要: In three experiments, the effects of venipuncture on plasma cortisol concentrations were studied in loose-housed dairy cows. Exp. 1, two blood samples collected 18 min apart alternate days from 20 cows for studying their adrenocortical response to a single venipuncture. To further evaluate effect anticipating venipuncture, 2, 15 sequentially venipunctured once daily 12 successive randomized order groups five, starting apart. 3, 10 primiparous used study habituation serial sampling (i.e., collection five by apart). accustomed handling, jugular puncture did not affect later. Average varied between 2.07 ± .38 and 3.81 .56 ng/mL first (t = 0) 1.43 .15 2.61 .72 second 18) samples. Likewise, when sampled day, within influence (P > .05) concentrations. contrast, that less being handled showed an average increase During sessions, however, decrease or repeated at group level .05). Between individuals, maximum (4.5 22.6 ng/mL), time which reached its (30 60 min), consistency pattern over series largely. The results this show handling restrained, baseline can be measured are l after approaching cow. When need min, may induce concentration, seems depend experience animals individual differences.