التفاصيل البيبلوغرافية
| العنوان: |
Influence of Prepubertal Dietary Regimen on Mammary Growth of Holstein Heifers |
| المؤلفون: |
Capuco, A.V., Smith, J.J., Waldo, D.R., Rexroad, C.E. |
| المصدر: |
Journal of Dairy Science; December 1995, Vol. 78 Issue: 12 p2709-2725, 17p |
| مستخلص: |
One hundred-sixteen Holstein heifers (mean BW, 175kg) were randomly assigned to diets of alfalfa silage or corn silage and were fed to gain approximately 725 or 950 g/d in order to study the influence of prepubertal diet and rate of gain on mammary growth and milk production. Blood was collected before puberty for hormone determination, and 8 heifers per group were killed at puberty for evaluation of tissue variables. Serum growth hormone was reduced, and IGF-I was increased, in the group of heifers reared at a high rate of gain on the corn silage diet. Accompanying the decline in growth hormone, total mammary parenchymal DNA and RNA was reduced in heifers reared at a high rate of gain on the corn silage diet. Mammary parenchyma in heifers of the latter group contained a greater volume of adipocytes and a lower volume of epithelial cells than did mammary parenchyma in heifers of other groups. Data are consistent with previous investigations that showed a deleterious effect of prepubertal rapid weight gain on mammogenesis when accompanied by excess body fat deposition. However, this effect did not cause a decline in subsequent milk production. |
| قاعدة البيانات: |
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