Metabolic and lactational responses during recombinant bovine tumor necrosis factor-alpha treatment in lactating cows
2003
Kushibiki, S. | Hodate, K. | Shingu, H. | Obara, Y. | Touno, E. | Shinoda, M. | Yokomizo, Y.
This study examined the effects of recombinant bovine tumor necrosis factor-alpha(rbTNF) administration on metabolic and hormonal responses and lactational performance indairy cows. Twelve lactating Holstein cows were injected subcutaneously with rbTNF (2.5microgram per kg per d) or saline (3 ml per head per d) at 1200 h daily for 7 d (d 0 - 6) and usedin a crossover design. The rbTNF treatment induced increases in plasma haptoglobin,nonesterified fatty acid, cortisol, and growth hormone levels compared with the control levels.The rbTNF-treated cows had lower triiodothyronine and insulin-like growth factor-1concentrations than control cows. In a somatoliberin challenge on d 6, the somatotropin responseto somatoliberin (0.25 micrograms/kg) was smaller in the rbTNF group than in the control. TherbTNF treatment also produced increases of the nitrite plus nitrate concentration in plasma andmilk during the period between d 1 and 7. Milk yield was reduced by rbTNF administration fromd 1 to 8. The percentage of milk fat was increased on d 1 - 7 by rbTNF treatment, but milkprotein content in the rbTNF group was decreased on d 5 and 7 as compared with that in thecontrol group. These results support the possibility that tumor necrosis factor-alpha is responsiblefor the changes in hormone secretion, milk production and composition, and inflammatoryparameters observed during coliform mastitis.
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