Effect of Level of Dietary Sulfur on in Vitro True Digestibility of a Commercial Ration Fed to Dorper Wethers

It is believed that sulfur may reduce palatability of lamb, but the resulting effect on digestibility is not clear. The primary objective of this study was to evaluate the effect of dietary sulfur on in vitro true digestibility (IVTD) of a commercial ration fed to eight dorper wethers (29.87 ± 0.52 kg BW). A secondary objective was to determine the effect of sulfur treated rumen fluid on digestibility of diets containing two levels of sulfur. Treatments consisted of 0 (CON) or 0.3 (SUL) % sulfur mixed into the ration of eight dorper wethers (29.87 ± 0.52 kg BW) consuming a commercial growing ration (Purina® Honor Show Chow Show lamb Grower 15% DX Medicated feed) with chopped coastal hay mixed at 90%:10%. Wethers were individually housed for the duration of the 56 d trial. Ground feedstuff samples containing CON or SUL treatments were weighed into F57 nylon filter bags in quadruplicate. Sheep were slaughtered 56 d after commencing sulfur inclusion. Gastrointestinal tracts were collected during slaughter to allow for rumen fluid collection. Rumen fluid was processed and IVTD protocol performed in accordance with ANKOM (2005) utilizing an ANKOM Daisy^II Incubator. Data were analyzed using the MIXED procedure of SAS 9.3 (SAS Inst. Inc., Cary, NC). Sulfur had no effect (P = 0.16; 85.20 vs 83.00% IVTD, respectively) on IVTD of CON vs. SUL feedstuffs. Rumen fluid from SUL sheep did not differ in its ability to degrade feedstuffs when compared to rumen fluid from CON sheep (P = 0.81; 84.37% vs 83.83% IVTD for CON vs SUL rumen fluid, respectively). Results suggest that dietary sulfur could be altered to benefit lamb palatability without affecting digestibility.