Teagasc, Animal & Grassland Research and Innovation Center, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
Teagasc, Animal & Grassland Research and Innovation Center, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
J Dairy Sci. 2019 May;102(5):4464-4475. doi: 10.3168/jds.2018-15195. Epub 2019 Mar 14.
The objective of this study was to assess the effect of treating cows with teat sealant only compared with antibiotic plus teat sealant at drying off on weekly somatic cell count, potential intramammary infection, and milk production across the entire subsequent lactation. In 3 research herds in the south of Ireland, cows with SCC that did not exceed 200,000 cells/mL in the previous lactation (LowSCC) were randomly assigned to 1 of 2 treatments at drying off: internal teat sealant alone (ITS) or antibiotic plus teat sealant (AB+ITS). Cows with SCC that exceeded 200,000 cells/mL in the previous lactation were treated with AB+ITS and included in the analyses as a separate group (HighSCC). Weekly individual animal composite SCC records were available for 654 cow lactations and were transformed to somatic cell scores (SCS) for the purpose of analysis. Data were divided into 3 data sets to represent records obtained (1) up to 35 DIM, (2) up to 120 DIM, and (3) across the lactation. Foremilk secretions were taken from all quarters at drying off, at calving, 2 wk after calving, and in mid-lactation and were cultured to detect the presence of bacteria. The LowSCC cows treated with ITS alone had higher daily milk yield (0.67 kg/d) across lactation compared with LowSCC cows treated with AB+ITS. The LowSCC cows treated with ITS alone had higher SCS in early, up to mid, and across lactation compared with LowSCC cows treated with AB+ITS. We detected no difference in weekly SCS of LowSCC cows treated with ITS alone and SCS of HighSCC cows. The least squares means back-transformed SCC across lactation of the LowSCC cows treated with ITS alone, LowSCC cows treated with AB+ITS, and HighSCC cows were 41,523, 34,001, and 38,939 cells/mL respectively. The odds of LowSCC cows treated with ITS alone having bacteria present in their foremilk across lactation was 2.7 (95% confidence interval: 1.91 to 3.85) and 1.6 (1.22 to 2.03) times the odds of LowSCC cows treated with AB+ITS and of HighSCC cows treated with AB+ITS, respectively. In this study, Staphylococcus aureus was the most prevalent pathogen isolated from the population. Recategorizing the threshold for LowSCC cows as ≤150,000 cells/mL or ≤100,000 cells/mL in the previous lactation had no effect on the results. The results indicate that herds with good mastitis control programs may use ITS alone at dry-off in cows with SCC <200,000 cells/mL across lactation with only a small effect on herd SCC.
本研究旨在评估在干奶期仅用乳头密封剂处理奶牛与用抗生素加乳头密封剂处理奶牛相比，对每周体细胞计数、潜在的乳腺炎感染和整个泌乳期产奶量的影响。在爱尔兰南部的 3 个研究牛群中，上一个泌乳期体细胞计数（SCC）不超过 200,000 个细胞/ml 的奶牛（低 SCC）随机分为 2 种干奶期处理方法之一：仅使用乳头密封剂（ITS）或抗生素加乳头密封剂（AB+ITS）。上一个泌乳期 SCC 超过 200,000 个细胞/ml 的奶牛用 AB+ITS 治疗，并作为一个单独的组进行分析（高 SCC）。共有 654 头奶牛的每周个体复合 SCC 记录可用，并为分析目的转换为体细胞评分（SCS）。数据分为 3 个数据集，分别代表（1）至 35 天、（2）至 120 天和（3）整个泌乳期的记录。在干奶期、分娩时、分娩后 2 周和泌乳中期，从所有乳区采集前奶样进行细菌培养。单独用 ITS 治疗的低 SCC 奶牛在整个泌乳期的日产量（0.67kg/d）高于用 AB+ITS 治疗的低 SCC 奶牛。单独用 ITS 治疗的低 SCC 奶牛在泌乳早期、中期和整个泌乳期的 SCS 均高于用 AB+ITS 治疗的低 SCC 奶牛。我们没有发现单独用 ITS 治疗的低 SCC 奶牛的每周 SCS 与高 SCC 奶牛的 SCS 之间有差异。单独用 ITS 治疗的低 SCC 奶牛、用 AB+ITS 治疗的低 SCC 奶牛和高 SCC 奶牛整个泌乳期的最小二乘均值反转换 SCC 分别为 41523、34001 和 38939 个细胞/ml。单独用 ITS 治疗的低 SCC 奶牛在整个泌乳期前奶中存在细菌的可能性是用 AB+ITS 治疗的低 SCC 奶牛和高 SCC 奶牛的 2.7（95%置信区间：1.91 至 3.85）和 1.6（1.22 至 2.03）倍。在这项研究中，金黄色葡萄球菌是从人群中分离出的最常见病原体。将低 SCC 奶牛在上一个泌乳期的阈值重新分类为≤150,000 个细胞/ml 或≤100,000 个细胞/ml，对结果没有影响。结果表明，在 SCC＜200,000 个细胞/ml 的泌乳期奶牛中，具有良好乳腺炎控制计划的牛群可以单独使用 ITS 在干奶期进行处理，对牛群 SCC 的影响很小。
