When we talk about flock productivity, we often focus on genetics, nutrition, or parasite management. But one of the most overlooked drivers of lamb survival and ewe longevity is udder health. Mastitis is the condition most producers recognize. In its clinical form, ewes develop painful, swollen udders, and abnormal milk. Severe cases, such as the dreaded “blue bag,” can threaten the ewe’s life as well as her lambs. Subclinical mastitis, however, is more insidious. The milk may look normal, yet somatic cell counts (an indication of inflammation) are high, milk production is reduced, and over time, the udder tissue hardens and becomes fibrotic. Our studies suggest up to 20% of a flock may be affected with subclinical mastitis, most commonly caused by gram positive bacteria (non-aureus staphylococcus species). Over half of these ewes are in their most productive years (under 5 years old) really highlighting the importance of this problem for long-term flock productivity. Unlike dairy production systems, there are few opportunities to check udder health in grazing sheep. The first objective of the study was to identify the best time in lactation to screen ewes for udder health. Initial data suggests weaning will give us the greatest chances of identifying ewes within the flock with mastitis. According to a survey we conducted in CA, <35% of sheep producers check udder health at weaning (Busch, 2024). The current objective is to study treatment strategies. Sample collection and data analysis is ongoing to ensure confidence in our results. In the future we would like to continue to study alternative mastitis control strategies and communicate these practical applications at our lambing schools.
