Association between energy balance and luteal function in lactating dairy cows

Area of Science:

• Veterinary Science
• Animal Reproduction
• Dairy Science

Background:

• Lactating dairy cows frequently experience negative energy balance postpartum.
• Energy balance is crucial for metabolic and reproductive functions in dairy cows.

Purpose of the Study:

• To investigate the relationship between energy balance and progesterone secretion in lactating dairy cows.
• To understand how energy deficits affect reproductive hormone profiles.

Main Methods:

• Studied 32 lactating Holstein cows from parturition to 100 days postpartum or conception.
• Measured feed intake, milk production, body weight, and calculated daily energy balance.
• Assessed progesterone concentrations in milk every 3 days.

Main Results:

• 81% of cows experienced negative energy balance for at least 4 days postpartum.
• Energy balance within 9 days postpartum positively correlated with progesterone in subsequent luteal phases.
• The timing and severity of negative energy balance reduced progesterone during postpartum estrous cycles.

Conclusions:

• Spontaneous caloric deficits in lactating cows reduce progesterone secretion.
• Negative energy balance, influenced by timing and magnitude, is a key factor modulating progesterone levels.
• Infertility in dairy cows may be linked to negative energy balance and subsequent reduced progesterone secretion.