Sulfate supplementation of growing goats: effects on performance, acid-base balance, and nutrient digestibilities.
Castrated male goat kids (20 Alpine, 12 Angora) were individually fed isonitrogenous and isoenergetic diets containing 2.28% N and S (added as CaSO4) at either .11 (basal), .20, .28, or .38% of dietary DM. Sulfate supplementation during the 8-wk growth trial quadratically increased ADG (P < .05) and tended to increase quadratically the DMI (P < .07) of goats, with a peak value for the .20% S diet. Even when analyzed using DMI as a covariate, ADG was quadratically increased (P < .05) by added S. Sulfate supplementation linearly increased (P < .001) S intake, fecal S output, and S retention. Sulfate supplementation tended to increase quadratically (P < .06) the blood plasma concentration of L-lactate. However, sulfate supplementation did not significantly affect (P > .10) plasma sulfate, plasma cystine, ruminal ammonia N concentrations, or purine N content of isolated ruminal bacteria. Sulfate supplementation quadratically increased (P < .05) fractional N retention. Urinary output of uric acid increased quadratically (P < .01) with S supplementation, presumably reflecting ruminal bacterial protein synthesis. Calculated by regression, the optimal dietary S content for maximum ADG was .22% S (N:S = 10.4:1), for maximum DMI it was .24% S (N:S = 9.5: 1), for maximum N retention it was .23% (N:S = 9.9: 1), and for maximum absorbed N retained it was .22% (N:S = 10.4:1). These results support the current estimate of the S requirement of goats for growth (N:S = 10:1).
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E. (Kika) de la Garza Institute for Goat Research, Langston University, OK 73050.
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D000136:Acid-Base Equilibrium / Q000187:drug effects*; D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D003545:Cysteine / Q000097:blood; D003553:Cystine / Q000097:blood; D004063:Digestion / Q000187:drug effects*; D004435:Eating / Q000187:drug effects; D005527:Food, Fortified; D006041:Goats / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000032:analysis / Q000097:blood; D008297:Male; D011897:Random Allocation; D012044:Regression Analysis; D012417:Rumen / Q000737:chemistry / Q000187:drug effects; D013431:Sulfates / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D013455:Sulfur / Q000032:analysis; D015430:Weight Gain / Q000187:drug effects*
D001786:Blood Glucose; D007773:Lactates; D013431:Sulfates; D003553:Cystine; D013455:Sulfur; D003545:Cysteine