Nutritional Alternative to Bovine Wonderbra

Recent dairy research reveals heifer mammary gland growth and subsequent lifetime lactation performance can be improved through feeding alternating ‘restricted’ and ‘adequate’ energy rations at defined developmental stages.

Specifically, reintroduction of an ‘adequate’ energy ration during the last trimester of a heifer’s first gestation activates gene pathways and endocrine signals, resulting in significant acceleration of anabolic processes over her entire body. This process is called compensatory growth.

Inducing whole-body compensatory growth during late gestation, when mammary development is already elevated, also triggers additional up-regulation of genes responsible for increased mammary cell proliferation. Consequently, a significant increase in number and differentiation of functional mammary cells occurs, conferring persistent, positive effects on milk volume over subsequent lactations.

Nutritionally-induced mammary cell proliferation during late gestation is also associated with epigenetic changes in mammary cell gene expression, due to alterations in DNA methylation patterns. Mammary gene expression changes become ‘metabolically imprinted’ on the cell, resulting in permanent expression changes that are transferred to daughter cells.

Metabolic imprinting positively influences cellular production over subsequent lactations by:

• Significantly increasing expression of the β-casein gene, thereby enhancing subsequent translation of the important milk protein, casein
• Increasing translation of the enzyme (γ-glutamyltranspeptidase) that enhances the entrance of amino acids into the mammary cell, thereby further increasing milk protein levels
• Decreasing translation of an enzyme (caspase-3-enzyme) responsible for programmed cell death of the mammary gland, thereby prolonging lactation period
  

These advances in heifer nutrition will confer significant economic advantages to the Australian dairy industry. Farmers will derive benefit from an estimated 10% yield/quality improvement and also from reduced feed costs associated with the energy ‘restriction’ ration...this all adds up to more money in the bank for Australian dairy farmers!

Primary Resource:

Park, C.S., 2005. Role of compensatory mammary growth in epigenetic control of gene expression. The FASEB Journal, 19, 1586-1591.

Secondary Resource:

Ford, J.A., Park, C.S., 2001. Nutritionally directed compensatory growth enhances heifer development and lactation potential. Journal of Dairy Science, 84, 1669-1678.

Posted By Jules Dowsett (40117548)