Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Dairy Sci. 2011 Dec;94(12):6011-20. doi: 10.3168/jds.2011-4463.
The purpose of this study was to determine the effect of oral propylene glycol (PG) administration on ketosis resolution and milk yield in cows diagnosed with subclinical ketosis (SCK). Cows from 4 freestall dairy herds (2 in New York and 2 in Wisconsin) were each tested 6 times for SCK from 3 to 16 d in milk on Mondays, Wednesdays, and Fridays. Subclinical ketosis was defined as a β-hydroxybutyrate (BHBA) concentration of 1.2 to 2.9 mmol/L, [corrected] and clinical ketosis was defined as ≥ 3.0 mmol/L. [corrected]. Cows with SCK were randomized to the treatment group (oral PG) or control group (no PG); treatment cows were drenched with 300 mL of PG once daily from the day they tested 1.2 to 2.9 mmol/L [corrected] until the day they tested <1.2 mmol/L. [corrected]. Outcomes evaluated for all farms included time from SCK until BHBA test <1.2 mmol/L [corrected] or until BHBA test ≥ 3.0 mmol/L. [corrected]. Individual milk weights for the first 30 d of lactation were evaluated for the 3 farms monitoring daily milk. Semiparametric proportional hazards models were used to evaluate time to event outcomes; repeated-measures ANOVA was used to assess milk weights. A total of 741 of 1,717 (43.2%) eligible enrolled cows had at least one BHBA test of 1.2 to 2.9 mmol/L. [corrected]. Of these, 372 were assigned to the treatment group and 369 to the control group. Based on hazard ratios, PG-treated cows were 1.50 times more likely (95% confidence interval=1.26 to 1.79) to resolve their SCK and 0.54 times less likely (95% confidence interval=0.34 to 0.86) to develop clinical ketosis than control cows. Across the 3 herds measuring individual milk weights, treated cows produced 0.23 kg more milk per milking in the first 30 d of lactation than control cows, for a total difference of 0.69 kg/cow per day. After identification of a treatment by herd interaction, stratification by herd showed that treated cows produced more milk per milking on farm A (0.44 kg) and farm B (0.53 kg) in the first 30 d of lactation than control cows, for a total difference of 1.34 and 1.59 kg/d, respectively; milk production did not differ (0.02 kg per milking) between the 2 groups on farm D. These results show the positive effects of oral PG administration in fresh cows with SCK by helping to resolve SCK and preventing clinical ketosis. In addition, oral PG improves milk yield during early lactation in cows diagnosed with SCK.
本研究旨在确定口服丙二醇（PG）对亚临床酮病（SCK）奶牛酮症缓解和产奶量的影响。来自 4 个自由卧床奶牛场（纽约 2 个，威斯康星 2 个）的奶牛，从产犊后第 3 天到第 16 天，每周一、三、五进行 6 次 SCK 检测。亚临床酮病定义为β-羟丁酸（BHBA）浓度为 1.2 至 2.9mmol/L，[已校正]临床酮病定义为≥3.0mmol/L。[已校正]。患有 SCK 的奶牛被随机分配到治疗组（口服 PG）或对照组（无 PG）；治疗组奶牛从检测到 1.2 至 2.9mmol/L[已校正]的那天开始，每天口服 300 毫升 PG，直到检测到<1.2mmol/L[已校正]。[已校正]。所有农场评估的结果包括从 SCK 到 BHBA 检测<1.2mmol/L[已校正]或 BHBA 检测≥3.0mmol/L[已校正]的时间。[已校正]。监测每日产奶量的 3 个奶牛场评估了产犊后前 30 天的个体产奶量。使用半参数比例风险模型评估事件时间结果；使用重复测量方差分析评估产奶量。共有 1717 头符合条件的奶牛中有 741 头（43.2%）至少有一次 BHBA 检测为 1.2 至 2.9mmol/L。[已校正]。其中 372 头被分配到治疗组，369 头被分配到对照组。基于风险比，PG 治疗组奶牛更有可能（95%置信区间=1.26 至 1.79）在 SCK 中得到缓解，并且不太可能（95%置信区间=0.34 至 0.86）发展为临床酮病，而对照组奶牛。在测量个体产奶量的 3 个奶牛场中，治疗组奶牛在产犊后前 30 天的每次挤奶量比对照组多 0.23 公斤，每天总差异为 0.69 公斤/头。在确定了治疗与牛群的相互作用后，按牛群分层显示，治疗组奶牛在产犊后前 30 天的每次挤奶量比对照组多 0.44 公斤（农场 A）和 0.53 公斤（农场 B），总差异分别为 1.34 和 1.59 公斤/天；在农场 D，两组之间的产奶量没有差异（每次挤奶 0.02 公斤）。这些结果表明，口服 PG 治疗对 SCK 初产奶牛具有积极作用，有助于缓解 SCK 并预防临床酮病。此外，口服 PG 可提高 SCK 奶牛产犊后早期的产奶量。
