Department of Animal Science and Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, Iowa 50011, USA.
J Anim Sci. 2012 Nov;90(11):3945-53. doi: 10.2527/jas.2011-4512. Epub 2012 Jun 4.
Ninety-six crossbred yearling steers (321 ± 29 kg BW) were used to determine the effects of feeding cattle a high S diet on pasture before receiving a high S diet in the feedlot. Steers were blocked by BW, allocated to 2.4-ha bromegrass (Bromus inermis L.) pastures (n = 4 plots per treatment), and supplemented at 1% BW with either low S dried distillers grains with solubles (DDGS; 0.34% total diet S; LS) or LS DDGS with additional S (0.47% total diet S; HS) from NaSO(4) for 36 d. On d 37, steers moved into the feedlot where one-half remained on the previous S treatment and the other half switched treatments, resulting in 4 treatments (LS-LS, LS-HS, HS-LS, HS-HS; LS: 0.2 to 0.3% total diet S, HS: 0.5 to 0.6% total diet S; n = 6 feedlot pens per treatment). During the pasture period, forage mass offered, grazing residual mass, and in vitro digestible DM of forage did not differ among treatments (P > 0.40), and ADG did not differ (LS: 1.6 kg · d(-1), HS: 1.7 kg · d(-1), P = 0.54). Plasma Mg measured on d 35 was decreased by ≈ 5% in response to increased dietary S during the pasture period (P = 0.05), though no effect on plasma Mg was observed during finishing (P > 0.15). Plasma Cu concentrations on d 155 were ≈ 15% less (P = 0.02) in HS vs. LS steers, and d 155 liver Cu concentrations were ≈ 51% less in HS vs. LS steers (P = 0.01). Increased dietary S during the feedlot period decreased ADG by ≈ 10% (P = 0.01) and tended to decrease HCW by ≈ 5% (P = 0.06) compared with LS steers. Steers receiving the HS diet had increased stearic acid (C18:0) and heptadecanoic acid (C17:0; P = 0.04 and 0.01, respectively) percentages in rib facings collected at slaughter. Exposing cattle to greater S diets (0.47% S) during a forage-based diet did not influence later performance on high S feedlot diets (0.5 to 0.6% S); however, cattle fed high dietary S on pasture had greater fat cover at slaughter (P = 0.01), suggesting S may have influenced lipid metabolism.
九十六头杂交周岁阉牛（321 ± 29 公斤 BW）用于确定在肥育场接受高 S 日粮之前，在牧场上给牛喂食高 S 日粮对其的影响。根据 BW 对牛进行分组，分配到 2.4 公顷的布罗梅尔草（Bromus inermis L.）牧场上（每个处理 4 个小区），并以 1% BW 的比例用低 S 干燥酒精糟及其可溶物（DDGS；总日粮 S 含量 0.34%；LS）或 LS DDGS 加额外的 S（总日粮 S 含量 0.47%；HS）进行补充，添加物来自 NaSO(4)，持续 36 天。在第 37 天，牛转移到肥育场，其中一半继续接受以前的 S 处理，另一半则改变处理方式，从而产生 4 种处理（LS-LS、LS-HS、HS-LS、HS-HS；LS：0.2 到 0.3% 总日粮 S，HS：0.5 到 0.6% 总日粮 S；每个处理 6 个肥育场围栏）。在牧草地期间，供料量、放牧残余量和饲料的体外可消化 DM 之间在处理之间没有差异（P > 0.40），并且 ADG 也没有差异（LS：1.6 公斤·d(-1)，HS：1.7 公斤·d(-1)，P = 0.54）。在牧草地期间，由于日粮 S 的增加，血浆 Mg 在第 35 天下降了约 5%（P = 0.05），但在育肥期间未观察到对血浆 Mg 的影响（P > 0.15）。在第 155 天，HS 组的血浆 Cu 浓度比 LS 组低约 15%（P = 0.02），而 HS 组的第 155 天肝脏 Cu 浓度比 LS 组低约 51%（P = 0.01）。肥育期日粮 S 的增加使 ADG 降低了约 10%（P = 0.01），并使 HCW 降低了约 5%（P = 0.06），与 LS 组相比。与 LS 组相比，接受 HS 日粮的牛在屠宰时收集的肋排骨面中的硬脂酸（C18:0）和十七烷酸（C17:0）的百分比增加（P = 0.04 和 0.01）。在基于牧草的日粮中让牛暴露于更高的 S 日粮（0.47% S）并不影响以后对高 S 肥育场日粮（0.5 到 0.6% S）的表现；然而，在牧场上喂食高膳食 S 的牛在屠宰时具有更大的脂肪覆盖（P = 0.01），这表明 S 可能影响了脂肪代谢。
