Administration of chromium picolinate and meloxicam alleviates regrouping stress in dairy heifers

Abstract

Objective: This research was performed to investigate effect of administering chromium (Cr) and meloxicam (MEL) on growth performance, cortisol and blood metabolite, and behaviors in young regrouped heifers.Methods: Fifty Holstein dairy heifers (body weight (BW) 198 ± 32.7 kg and 6.5 ± 0.82 months of age) were randomly assigned to non-regrouped group or four regrouped groups. Non-regrouped animals were held in the same pen throughout entire experimental period (NL: non-regrouping and administration of lactose monohydrate (LM; placebo). For regrouping groups, two or three heifers maintained in four different pens for 2 weeks were regrouped into a new pen and assigned to one of four groups: regrouping and LM administration (RL); regrouping and Cr administration (RC); regrouping and MEL administration (RM), and regrouping and Cr and MEL administration (RCM).LM (1 mg/kg BW), Cr (0.5 mg Cr picolinate/kg dry matter intake), and MEL (1 mg/kg BW) were orally administered immediately before regrouping. Blood was collected before regrouping (0 h) and at 3, 9, and 24 h and 7 and 14 d thereafter. Behaviors were recorded for 7 consecutive days after regrouping.Results: Average daily gain was lower (P < 0.05) in RL than NL heifers, but was higher (P < 0.05) in RM, RC, and RCM than RL heifers. RL heifers had higher (P < 0.05) cortisol than NL heifers on d 1 after regrouping. The cortisol concentrations in RC, RM, and RCM groups were lower (P A c c e p t e d A r t i c l e 4 < 0.05) than in RL treatment 1 d after regrouping. Displacement behavior was greater (P < 0.05) in RL group than all other groups at 2, 3, and 6 d after regrouping. Conclusion:Regrouping caused temporal stress, reduced growth performance, and increased displacement behavior in heifers. Administering Cr and MEL recovered the retarded growth rate and reduced displacement behavior, thereby alleviating regrouping stress.