Non-nutritional factors affecting lactation persistency in dairy ewes: a review

Milk production is largely related to the shape of the lactation curve. Key elements of the lactation pattern
are peak yield, which is the maximum daily yield reached during lactation, and lactation persistency,
which is the medium rate of milk yield decrease after the lactation peak. The ideal lactation curve
should have a reasonably high peak and a flat trend afterwards. A more persistent lactation is desirable
because it is related to better animal health and reduction of feeding costs. Effective strategies to improve
lactation persistency require a deep understanding of the main factors that affect this trait, including
genetics, hormonal status and administration, udder morphology, seasonal changes, management, animal
health (e.g. mastitis), stress and nutrition. This review covers the effects of non-nutritional factors
on lactation persistency in dairy sheep.