8 pages, This study examined the impact of replacing soybean meal (SBM) for treated and untreated sesame meal (SM) with varying amounts of crude protein (CP) on nutrient intake and digestibility, milk composition, and ruminal parameters in lactating goats. Forty mid-lactation Murciano-Granadina goats were randomly allocated to four diets including (1) SBM (16.5% CP; CON); (2) untreated SM (USM; 16.5% CP). (3) formaldehyde-treated SM (FTSM; 16.5% CP), and (4) FTSM containing 14.5% CP (LPFT). FTSM goats had higher dry matter (DM) and nutrient intake than CON and LPFT, as observed for milk fat (P<0.001) and total solids (TS; P=0.001) yield. Milk fat content was higher with USM than LPFT (P<0.05). In general, the sum of milk saturated fatty acids (SFA) decreased, and milk unsaturated FA (UFA), monounsaturated FA (MUFA), polyunsaturated FA (PUFA), and long-chain FA (LCFA) increased by the inclusion of USM, and FTSM in the diet. Incorporation of FTSM in the diet decreased ruminal pH, ammonia nitrogen, and acetate molar proportion compared to CON and USM as observed with LPFT. Also, this inclusion increased total volatile FAs production and propionate proportion compared to CON and USM (P<0.001). In conclusion, substitution of SBM for FTSM in the diet of dairy goats can improve milk and milk component yield as well as health-promoting alterations in milk FAs profile. Furthermore, reducing dietary CP level along with FTSM inclusion in the diet may be considered as a proper tool in compensating the adverse effects of dietary CP deficiency and optimizing the productive performance of dairy goats utilizing lower amounts of nitrogen sources.
