Sulfate supplementation of alpine goats: effects on milk yield and composition, metabolites, nutrient digestibilities, and acid-base balance
1992
Qi, K. | Lu, C.D. | Owens, F.N.
Effects of sulfate supplementation on milk yield and composition, ruminal and blood metabolites, acid-base status, and nutrient digestibilities were determined using 30 multiparous, lactating Alpine does. Goats were fed isonitrogenous diets containing .16 (basal, .26, or .36% S (DM basis) during a 13-wk lactation trial that coincided with wk 3 to 15 of lactation. During wk 16 to 17, four does from each treatment were placed in a metabolism crate to measure nutrient digestibility and balance. Feed intake, yield of 4% fat-corrected milk, and milk S content were not affected by added S, but the goats fed the .26% S diet had a trend of higher persistency of lactation (P < .20). During wk 10 and 15 of lactation, milk solids-not-fat percentage was higher (P < .10) for does fed the .26% S diet. Sulfur supplementation resulted in quadratic decreases in ruminal ammonia N (P < .05) in wk 15 and in plasma urea N in wk 10 and 15 (P < .05) but in linear increases (P < .05) in ruminal protein S concentrations throughout the experiment. Added S had little effect on blood acid-base status. Apparent digestibilities of DM, OM, ash, ADF, and GE were increased linearly (P < .10) by added S. The milk N:S ratio remained constant. Increasing S from .16 to .26% of diet DM was beneficial to lactating Alpine goats during early lactation.
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