Ewes transitioning from late gestation to early lactation face a number of challenges including physiological stress, dietary changes, and metabolic adaptations, particularly when bearing and rearing multiple offspring. Furthermore, rumen microbial composition and function has been correlated with milk production and nutrient density in transitioning dairy cows. However, limited research has evaluated the rumen microbial community of ewes during early lactation. The objective of this study was to conduct a functional microbiological survey of the ewe rumen from parturition to weaning. We hypothesized that ewes would experience fermentative disturbances post-parturition and that the rumen microbiota, and consequently, circulating metabolites, would recover over time. Nine multiparous Polypay ewes bearing triplets were fed a lactation diet consisting of alfalfa hay and concentrate mix to meet protein and energy requirements. One lamb of each triplet set was randomly selected and placed on milk replacer 24 h after birth. The two lambs remaining on the ewe were weaned at 56 d of age. Blood and rumen samples from ewes were collected via jugular venipuncture and oral intubation, respectively, at 2, 7, and 15 d of lactation in addition to at the time of weaning. Rumen bacterial functional guilds were enumerated via serial dilution. Ruminal short-chain fatty acids (SCFA) were quantified via HPLC and serum metabolites by LC-MS. All data were analyzed using PROC Mixed with repeated measures in SAS (v. 9.4, SAS Inst. Inc., Cary, NC). Total starch-utilizing bacteria remained steady during early lactation but increased 100-fold by weaning (P = 0.03). In contrast, the starch-utilizing guild sub-population lactobacilli increased 10-fold by d 15 of lactation (P < 0.01) and remained constant through weaning (P > 0.05). No differences were found in the viable number of rumen cellulolytic bacteria (P = 0.37) throughout the study. Ruminal propionate concentrations increased 35% (P = 0.04) from d 2 to weaning and serum propionate (36.8 ± 4.42 µM; P = 0.08) and glucose (59.8 ± 2.97 mg dL-1; P < 0.01) peaked on d 15 of lactation. While ruminal acetate did not fluctuate in early lactation, it increased 58% by weaning (P < 0.01) leading to an 88% increase in serum acetate (P < 0.01). Ruminal butyrate increased 49% by d 15 (P = 0.01) and this was reflected in a 7-fold increase in serum butyrate (P = 0.02). However, serum β-hydroxybutyrate did not differ from parturition through weaning (P = 0.51). Results of this experiment demonstrate that rumen bacterial functional guilds, as well as rumen and serum metabolites, were lowest two days post-parturition and increased over the course of lactation. This may suggest that ruminal fermentation is suppressed post-parturition, which could have implications for early lactation management strategies of triplet-bearing ewes.

中文翻译：

---

87 三胞胎多腹母羊从分娩到断奶的功能性瘤胃微生物学调查

从妊娠晚期过渡到泌乳早期的母羊面临着许多挑战，包括生理压力、饮食变化和代谢适应，特别是在生育和抚养多个后代时。此外，瘤胃微生物的组成和功能与围产期奶牛的产奶量和营养密度相关。然而，评估泌乳早期母羊瘤胃微生物群落的研究有限。本研究的目的是对母羊从分娩到断奶的瘤胃进行功能性微生物学调查。我们假设母羊在产后会经历发酵紊乱，瘤胃微生物群以及循环代谢物会随着时间的推移而恢复。九只产三胞胎的多产母羊被喂以由苜蓿干草和浓缩混合物组成的哺乳期饲料，以满足蛋白质和能量需求。每组三胞胎中随机选择一只羔羊，并在出生后 24 小时使用代乳品。母羊身上剩下的两只羔羊在56日龄时断奶。除断奶时外，分别在哺乳期 2、7 和 15 天通过颈静脉穿刺和口腔插管收集母羊的血液和瘤胃样本。通过连续稀释来计数瘤胃细菌功能群。通过 HPLC 定量瘤胃短链脂肪酸 (SCFA)，通过 LC-MS 定量血清代谢物。所有数据均使用 PROC Mixed 进行分析，并在 SAS 中进行重复测量（v. 9.4，SAS Inst. Inc.，Cary，NC）。淀粉利用细菌总数在哺乳早期保持稳定，但断奶后增加了 100 倍（P = 0.03）。相反，利用淀粉的公会亚群乳酸杆菌在哺乳期第15天增加了10倍（P＜0.01），并且在断奶期间保持恒定（P＞0.05）。在整个研究过程中，瘤胃纤维素分解菌的存活数量没有发现差异（P = 0.37）。从第 2 天到断奶，瘤胃丙酸浓度增加了 35% (P = 0.04)，血清丙酸 (36.8 ± 4.42 µM；P = 0.08) 和葡萄糖 (59.8 ± 2.97 mg dL-1；P < 0.01) 在第 15 天达到峰值。哺乳期。虽然瘤胃乙酸盐在哺乳早期没有波动，但断奶后增加了 58% (P < 0.01)，导致血清乙酸盐增加 88% (P < 0.01)。到第 15 天，瘤胃丁酸增加了 49%（P = 0.01），这反映在血清丁酸增加了 7 倍（P = 0.02）。然而，血清β-羟基丁酸与分娩至断奶期间没有差异（P = 0.51）。该实验的结果表明，瘤胃细菌功能群以及瘤胃和血清代谢物在产后两天最低，并在哺乳过程中增加。这可能表明瘤胃发酵在产后受到抑制，这可能对三胞胎母羊的早期泌乳管理策略产生影响。