64 Feeding Chicory-plantain Silage and Se-yeast on Lactating Ewe Subjected to Intramammary Infection: Effect on Performance and Milk Quality

Abstract

Abstract Our objective was to test the effect on milk yield and quality of feeding a combination of chicory-plantain and Se-yeast in lactating ewes subjected to intramammary infection (IMI). For this purpose, we enrolled 28 Polypay ewes from a prior study where they received chicory (CS) or grass (GC) silage and supplemented with 3.6 mg of Se/day as Se-yeast (DiaMune, Diamond V) (Y) or not (C) for 2 months. For the present study, ewes were kept on the original dietary regiment except the CS group received a chicory-plantain silage (50% each). Ewes were milked twice daily and milk was collected for analysis of components and somatic cell count (SCC). IMI was induced by injecting 2×107 CFU of Strep. uberis in both glands. Data were analyzed using GLIMMIX (SAS) with time, silage, and Se and their interactions as the fixed effects and ewe as random effect with significance declared P ≤ 0.05. SCC increased 8-fold 24h post-IMI and remained at that level until the end of the experiment with higher values pre-IMI in GC-Y animals but no difference post-IMI. Milk yield drastically decreased post-IMI but was not affected by treatments. Protein, fat, solids, amount of de novo fatty acids, and amount of C16:0 were larger in milk of ewes fed chicory-plantain compared to grass silage. Supplementation of Se had minor effect on milk components with a tendency (P = 0.07) to decrease fat, solids, and amount of de novo fatty acids. Amounts of C18:0, C18:1, and preformed fatty acids in milk were increased by Se supplementation in ewes fed grass while decreased in ewes fed chicory. The use of Strep. uberis was effective in inducing IMI in ewes with chicory-plantain improving several milk components while Se supplementation had minor effects. The combination of chicory and Se did not improve the response to IMI.