Mammary growth during lactation: implications for increasing milk yield

Area of Science:

• Animal Science
• Lactation Biology
• Dairy Science

Background:

• Milk yield is primarily determined by the number and activity of mammary secretory cells.
• Cellular dynamics during lactation vary between species, influencing milk production patterns.

Purpose of the Study:

• To investigate the role of mammary secretory cell population size and proliferation in regulating milk yield.
• To explore strategies for increasing milk yield by manipulating mammary gland growth and cell maintenance during lactation.

Main Methods:

• Comparative analysis of mammary cell dynamics in rats and goats during different lactation stages.
• Assessment of the effects of milking frequency and surgical interventions (hemimastectomy) on cell number and proliferation.
• Evaluation of compensatory growth mechanisms in the mammary gland.

Main Results:

• In rats, cell proliferation contributes significantly to increased milk yield from parturition to peak lactation.
• In goats, post-peak lactation decline in milk yield is linked to secretory cell loss.
• Increased milking frequency reduces cell loss, while hemimastectomy induces compensatory cell number maintenance and proliferation.

Conclusions:

• Mammary growth and cell proliferation can occur during established lactation, offering potential for yield enhancement.
• Strategies targeting cell proliferation and maintenance hold promise for improving dairy animal milk production.
• Understanding species-specific mammary gland plasticity is crucial for optimizing lactation performance.