Feeding formaldehyde-treated sesame meal to lactating Murciano-Granadina goats: implications on milk yield and composition, digestibility, rumen fermentation, and blood metabolites

Aim of study: To investigate the effect of substituting sesame meal (SM) treated with different levels of formaldehyde instead of soybean meal (SBM) on rumen fermentation, milk composition, and hemato-chemical parameters in lactating goats. Area of study: Kerman, Iran. Material and methods: Forty Murciano-Granadina goats in mid-lactation were allocated to four groups as a completely randomized design for 56 d. They were fed with diets containing: 1) SBM (control), 2) 12.5% untreated SM, 3) 12.5% treated SM with 0.8 g formaldehyde/100g crude protein (CP), and 4) 12.5% treated SM with 1.2 g formaldehyde/100g CP. Main results: The goats fed diet containing SM treated with 1.2 g of formaldehyde had greater (p < 0.01) intake of dry matter, CP and metabolizable energy (ME) than other groups. Milk yield and milk protein in goats fed diets containing 1.2 g formaldehyde-treated SM were greater than others (p < 0.01). Fat-corrected milk and total solids in groups fed diets containing formaldehyde-treated and untreated SM were greater than those in control (p < 0.01). Goats fed control diet showed a greater proportion of saturated fatty acids (SFA), and short and medium-chain FA in their milk compared to other groups (p < 0.01). Partial replacement of SBM with formaldehyde-treated or untreated SM increased milk unsaturated FA and long-chain FA (p < 0.01). Goats fed formaldehyde-treated SM had lower acetate production (p < 0.01). Research highlights: Partial replacement of SBM with formaldehyde-treated SM can be suggested to increase lactating goats' performance without adverse effects on their health.