Context Twin-bearing ewes may be unable to produce enough colostrum following birth to support the survival of two lambs. This causes the newborn lambs to be at risk of death due to starvation, mismothering, cold exposure and infection. Niacin has previously been demonstrated in cattle to increase immunoglobulin concentrations in colostrum, possibly due to niacin increasing blood flow, allowing the greater accumulation of nutrients and immunoglobulins in colostrum. High producing animals, such as the late gestation twin-bearing ewe, may not be able to produce enough niacin to meet their production requirements. Aims This experiment evaluated whether supplementation of niacin (vitamin B3) to late gestation twin-bearing ewes would increase colostrum production and composition (concentration of fat, lactose, protein and immunoglobulin G), and postnatal lamb growth. Methods A total of 24 artificially inseminated Merino ewes were weighed, body condition scored, aged and randomly allocated to a treatment – control treatment or with 5 g/day niacin supplemented for 2 weeks before lambing until 2–8 days post-lambing. Key results Colostrum production and immunoglobulin G concentration were similar between treatments (P > 0.05). Ewes supplemented with niacin produced significantly higher (P = 0.039) colostral protein at 12.54% compared with the control group ewes at 11.78%. Early lamb growth rates were unaffected (P > 0.05) by treatment. Conclusions Supplementation of ewes with 5 g/day niacin is not recommended to increase the production of colostrum and immunoglobulin G or to increase lamb growth rates following birth. Implications Further research into niacin supplementation, supplementation time and supplementation amount for production effects in late gestation ewes is warranted.

中文翻译：

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补充烟酸（维生素B3）的母羊初乳的生产和成分

背景 双胎母羊在出生后可能无法产生足够的初乳来维持两只羔羊的存活。这会导致新生的羔羊因饥饿、缺奶、寒冷暴露和感染而面临死亡风险。先前已在牛身上证明烟酸会增加初乳中的免疫球蛋白浓度，这可能是由于烟酸增加了血流量，从而使初乳中的营养物质和免疫球蛋白积累更多。高产动物，例如妊娠晚期的双胎母羊，可能无法产生足够的烟酸来满足其生产需求。目的 本实验评估了向妊娠晚期双胎母羊补充烟酸（维生素 B3）是否会增加初乳的产量和成分（脂肪、乳糖、蛋白质和免疫球蛋白 G 的浓度），和产后羔羊的生长。方法 总共对 24 只人工授精的美利奴母羊进行称重、身体状况评分、老化并随机分配到治疗组 - 对照治疗组或在产羔前 2 周至产羔后 2-8 天补充 5 g/天烟酸。主要结果 处理之间的初乳产量和免疫球蛋白 G 浓度相似（P > 0.05）。与对照组母羊的 11.78% 相比，补充烟酸的母羊产生显着更高的初乳蛋白 (P = 0.039)，为 12.54%。早期羔羊的生长率不受处理的影响（P > 0.05）。结论 不建议为母羊补充 5 g/天的烟酸来增加初乳和免疫球蛋白 G 的产量或增加出生后羔羊的生长速度。影响 对烟酸补充剂的进一步研究，