Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 Saarentaus, Finland.
Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 Saarentaus, Finland; Department of Agricultural Sciences, University of Helsinki, PL 27, 00014 Helsinki, Finland.
Prev Vet Med. 2021 Mar;188:105268. doi: 10.1016/j.prevetmed.2021.105268. Epub 2021 Jan 19.
Mastitis remains the most expensive disease of dairy cows, and antibiotic dry cow therapy (DCT) at dry-off is an important part of mastitis control. Regardless of the infection status, blanket DCT is administered to all quarters of all cows, which is controversial due to the worldwide problem of antimicrobial resistance. Even though selective DCT of only infected cows is a more sustainable approach, choosing animals for treatment is not always straightforward. Our aim was to evaluate whether the herd-level DCT approach is associated with early lactation udder health problems, taking into account the cow characteristics. The information source was 2015-2017 Dairy Herd Improvement data with 7461 multiparous cows from 241 Finnish dairy herds. Information on the herd-level DCT approach was obtained from farmers' questionnaire responses in 2017, and the three different approaches were selective DCT, blanket DCT, and no DCT. The statistical tool for the data analysis was a generalized linear mixed model with a random herd effect for binary outcomes and a linear mixed model with a random herd effect for a continuous outcome. The two binary outcomes were the odds of having high milk somatic cell count (SCC ≥ 200 000 cells/mL) on the first test-day within 5-45 days in milk (DIM) and the odds of mastitis treatment in early lactation up to 45 DIM. The third outcome was the mean milk lnSCC (× 1000 cells/mL) within 120 DIM. Selective DCT was the prevailing treatment practice in our data. Blanket DCT was associated with lower SCC after calving. Cows more likely to have high SCC after calving were older cows, cows with high average SCC during the previous lactation, and cows with high milk yield near dry-off. A mastitis treatment in the early lactation was more likely if, during the previous lactation, the cow had high average SCC, high peak milk production, or high milk yield near dry-off. Our findings indicate that DCT is still effective in mastitis control. Cows with high milk yield, especially near dry-off, and cows with persistently high SCC require attention when considering next lactation udder health.
乳腺炎仍然是奶牛最昂贵的疾病，干奶期的抗生素干奶牛疗法（DCT）是乳腺炎控制的重要组成部分。无论感染状况如何，所有奶牛的所有乳房都要进行 blanket DCT，由于全球范围内的抗生素耐药性问题，这一做法存在争议。尽管仅对感染奶牛进行选择性 DCT 是一种更可持续的方法，但选择治疗动物并不总是那么简单。我们的目的是评估 herd-level DCT 方法是否与早期泌乳期乳房健康问题相关，同时考虑奶牛的特征。信息来源是 2015-2017 年的奶牛群改良数据，其中包括来自芬兰 241 个奶牛场的 7461 头经产奶牛。关于 herd-level DCT 方法的信息是从 2017 年农民的问卷调查回复中获得的，有三种不同的方法，分别是选择性 DCT、blanket DCT 和不进行 DCT。数据分析的统计工具是二元结果的广义线性混合模型和连续结果的线性混合模型，都具有随机 herd 效应。两个二元结果是在泌乳 5-45 天内第一次检测日中 milk SCC 高（≥200 000 个细胞/ml）的几率和泌乳早期乳腺炎治疗的几率，直到 45 DIM。第三个结果是泌乳 120 天内的平均 milk lnSCC（×1000 个细胞/ml）。在我们的数据中，选择性 DCT 是主要的治疗方法。产后 blanket DCT 与 SCC 较低有关。产后更有可能 SCC 较高的奶牛是年龄较大的奶牛、上一个泌乳期平均 SCC 较高的奶牛和干奶期临近时产奶量较高的奶牛。在上一个泌乳期，如果奶牛的平均 SCC 较高、产奶高峰期较高或干奶期临近时产奶量较高，则更容易在泌乳早期进行乳腺炎治疗。我们的研究结果表明，DCT 仍然在乳腺炎控制中有效。产奶量较高的奶牛，尤其是干奶期临近时，以及 SCC 持续较高的奶牛，在下一个泌乳期乳房健康时需要特别注意。
