Artificial lighting during winter increases milk yield in dairy ewes

Area of Science:

• Animal Science
• Dairy Production
• Photoperiodism

Background:

• Sheep milk supply in Australia significantly decreases during winter months.
• Artificial lighting is a known method to boost milk yield in dairy animals, but data on dairy ewes is limited.
• Understanding photoperiod effects is crucial for optimizing winter milk production in sheep.

Purpose of the Study:

• To quantify the impact of long-day photoperiods on milk yield in dairy ewes during winter.
• To investigate the relationship between photoperiod, milk production, and plasma prolactin levels in ewes.
• To assess the effect of artificial lighting on milk composition in dairy ewes.

Main Methods:

• 220 East Friesian crossbred ewes were housed indoors after lambing.
• Ewes were divided into two groups: one under a long-day photoperiod (16h light) and a control group under natural day length.
• Milk yield, ewe weight, condition, milk composition, and plasma prolactin were monitored over 8 weeks.

Main Results:

• Ewes under the long-day photoperiod maintained a higher percentage of their initial milk yield (91.7%) compared to the control group (76.25%) by week 8.
• The divergence in milk yield between groups became apparent by week 2 of the treatment.
• Higher plasma prolactin levels were observed in ewes exposed to long-day photoperiods compared to controls, particularly at weeks 6, 7, and 8.

Conclusions:

• Dairy ewes housed under a long-day photoperiod during winter increase their milk production.
• Artificial lighting effectively stimulates milk production in ewes, likely mediated by elevated prolactin levels.
• The milk composition (lipid, protein, lactose) remained consistent between the photoperiod treatment groups.