Ma Junnan, Kok Akke, Goselink Roselinde M A, Lam Theo J G M, Kemp Bas, van Knegsel Ariette T M
Adaptation Physiology Group, Wageningen University & Research, Wageningen, the Netherlands.
Wageningen Livestock Research, Wageningen University & Research, Wageningen, the Netherlands.
J Dairy Res. 2022 Sep 21:1-8. doi: 10.1017/S0022029922000516.
This study aimed to evaluate the effect of an extended voluntary waiting period (VWP) on SCC, SCC elevations and clinical mastitis incidence during the complete lactation and the first 6 weeks of the next lactation. Holstein-Friesian dairy cows ( = 154) were blocked for parity, expected milk yield, calving season and breeding value for persistency and were randomly distributed across 3 VWP (50, 125, or 200 d: VWP-50, VWP-125, VWP-200). Cows were monitored from calving until 6 weeks into the next lactation, or until culling. An elevation of SCC in milk was defined as SCC in milk ≥200 000 cells/ml after two previous weeks with SCC < 200 000 cells/ml. Over the complete lactation, extending the VWP did not affect SCC elevations and the occurrence of clinical mastitis per lactation or per cow per year. There was no clear effect of VWP length on SCC in the complete lactation, except that multiparous cows in VWP-125 had a higher SCC compared with multiparous cows in VWP-50. Dry-off antibiotic usage per cow per year was lower in VWP-200 compared with VWP-50 for multiparous cows. In the first 6 weeks of the next lactation, cows in VWP-200 had a higher SCC compared with cows in VWP-50, with no effect of VWP on the number of elevations of SCC or the occurrence of clinical mastitis. Extending the VWP may therefore be used to reduce the frequency of transition periods and the associated use of dry-cow antibiotics, with limited impact on udder health, and a similar occurrence of SCC elevations and clinical mastitis per year.
本研究旨在评估延长自愿等待期（VWP）对整个泌乳期以及下一泌乳期前6周的体细胞计数（SCC）、SCC升高情况和临床型乳房炎发病率的影响。将154头荷斯坦-弗里生奶牛按胎次、预期产奶量、产犊季节和泌乳持续性育种值进行分组，并随机分配到3个VWP组（50天、125天或200天：VWP-50、VWP-125、VWP-200）。对奶牛从产犊开始监测，直至下一泌乳期第6周，或直至淘汰。牛奶中SCC升高定义为在前两周SCC<200 000个细胞/毫升之后，牛奶中SCC≥200 000个细胞/毫升。在整个泌乳期，延长VWP对每个泌乳期或每头奶牛每年的SCC升高情况和临床型乳房炎的发生没有影响。VWP时长对整个泌乳期的SCC没有明显影响，不过VWP-125组的经产奶牛SCC高于VWP-50组的经产奶牛。对于经产奶牛，VWP-200组每头奶牛每年的干奶期抗生素使用量低于VWP-50组。在下一泌乳期的前6周，VWP-200组奶牛的SCC高于VWP-50组奶牛，VWP对SCC升高次数或临床型乳房炎的发生没有影响。因此，延长VWP可用于减少围产期的频率以及干奶牛抗生素的相关使用，对乳房健康影响有限，且每年SCC升高情况和临床型乳房炎的发生率相似。
