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Response to ACTH Challenge in Female Dairy Calves in Relation to Their Milk Yield |
E. Szűcs, H. Fébel, J. Janbaz, Gy. Huszenicza, M. Mézes, A. T. Tran, Cs. Ábrahám, A. Gáspárdy, I. Györkös, J. Seenger, J. A. Nasser |
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Abstract |
Attempts have been made to establish relationship between the response to ACTH challenge in female calves, growth and first lactation performance. A total of 19 Holstein calves weighing 100 kg i. v. were given 0.50 IU of ACTH/kg BW.75 (EXACTHIN inj., Richter G., Budapest) at 60 days of age. Serial blood samples were taken at times 0, 0.5, 1, 2, 3, 4 and 5 hours and analyzed for cortisol, glucose insulin and FFA levels. From challenge series the area under the curve from time of administration and the following 5 h were calculated. Negative, and mostly loose relationship between response to ACTH challenge for cortisol, insulin, or FFA and ADWG during growth have been established (p>0.05) with positive one for glucose. Bivariate coefficients of correlation varied within the range from -0.35 to 0.15. Estimations reveal negative correlation between the length of first lactation and cortisol or insulin (r=-0.80, p<0.001 and r=-0.45, p<0.10, resp.) Close association between cortisol or insulin and actual first lactation milk yield was found (r=-0.48, p<0.10; r=-0.64, p<0.01, resp.). Close relationship between the response to ACTH challenge and milk protein yield was present only for insulin (r=-0.59, p<0.05). |
Keywords:
ACTH Challenge; Response; Cortisol; FFA; Insulin; Glucose |
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