Zambelis A, Robles I, DeVries T J
Department of Animal Biosciences, University of Guelph, 50 Stone Rd E, Guelph, ON, N1G 2W1, Canada.
Department of Animal Biosciences, University of Guelph, 50 Stone Rd E, Guelph, ON, N1G 2W1, Canada.
Prev Vet Med. 2019 Feb 1;163:1-6. doi: 10.1016/j.prevetmed.2018.12.009. Epub 2018 Dec 14.
The objective of this study was to examine associations of locomotion score, hygiene, body condition score (BCS), lying behavior, and milk production with dairy cow somatic cell count (SCC; low or high). Cows from 14 commercial free-stall dairy herds in Ontario, Canada were enrolled in a cross-sectional study. Each farm was visited for a total of 3 observation periods (at 5-wk intervals) on 2 occasions per period (7 d apart) until 3 Dairy Herd Improvement (DHI) milk tests had been completed. Upon immediate receiving of the results of each DHI test, lactating Holstein cows were selected according to SCC. Cows that ranked in the top 10% for SCC in each herd (≥200,000 cells/mL; n = 370) were first selected and paired based on parity and DIM to cows within the same herd with low SCC (≤100,000 cells/mL; n = 382). Lying behavior was recorded for selected cows for 6 d after each milk test sampling, using data loggers. On the visit where data loggers were attached, cows were scored for gait (1 = sound to 5 = lame) and hygiene of udder, lower legs, and upper legs/flank (1 = clean to 4 = dirty). On the visit where data loggers were removed 7 d later, BCS (1 = thin to 5 = fat) and hygiene were scored. Cows were then classified into each of the scoring categories for hygiene (clean: ≤ 2, dirty: ≥3), BCS (high: ≥4, normal: 3-3.5, low: ≤2.5), and gait (sound: ≤2, lame: ≥ 3). As compared to normal BCS cows, low BCS cows were associated with high SCC (OR = 1.57, 95% CI = 1.00-2.47). Cows with high SCC were associated with producing 2.2 ± 0.72 kg/d less milk than those with low SCC. As compared to normal BCS cows, low BCS cows were associated with reduced lying time (-27.2 ± 12.5 min/d), decreased lower leg hygiene (OR = 2.64, 95% CI = 1.08-6.46), and increased milk production (+2.9 ± 0.88 kg/d). These results suggest that low BCS may be a mediating factor among lying behavior, hygiene, and production level with high SCC.
本研究的目的是检验奶牛运动评分、卫生状况、体况评分（BCS）、躺卧行为和产奶量与奶牛体细胞计数（SCC；低或高）之间的关联。来自加拿大安大略省14个商业化散栏式奶牛场的奶牛被纳入一项横断面研究。每个农场共进行3个观察期（间隔5周），每个观察期进行2次访问（间隔7天），直至完成3次奶牛群改良（DHI）牛奶检测。在每次DHI检测结果立即出来后，根据SCC选择泌乳期荷斯坦奶牛。首先选择每个牛群中SCC排名前10%（≥200,000个细胞/毫升；n = 370）的奶牛，并根据胎次和产犊间隔天数与同一牛群中SCC较低（≤100,000个细胞/毫升；n = 382）的奶牛进行配对。在每次牛奶检测采样后，使用数据记录器对选定的奶牛的躺卧行为记录6天。在安装数据记录器的访问中，对奶牛的步态（1 = 正常至5 = 跛行）以及乳房、小腿和大腿/胁腹的卫生状况进行评分（1 = 清洁至4 = 脏污）。在7天后移除数据记录器的访问中，对BCS（1 = 瘦至5 = 胖）和卫生状况进行评分。然后将奶牛按照卫生状况（清洁：≤2，脏污：≥3）、BCS（高：≥4，正常：3 - 3.5，低：≤2.5）和步态（正常：≤2，跛行：≥3）的各个评分类别进行分类。与BCS正常的奶牛相比，BCS低的奶牛与高SCC相关（OR = 1.57，95% CI = 1.00 - 2.47）。SCC高的奶牛比SCC低的奶牛每天产奶量少2.2 ± 0.72千克。与BCS正常的奶牛相比，BCS低的奶牛躺卧时间减少（-27.2 ± 12.5分钟/天），小腿卫生状况下降（OR = 2.64，95% CI = 1.08 - 6.46），产奶量增加（+2.9 ± 0.88千克/天）。这些结果表明，低BCS可能是躺卧行为、卫生状况和高SCC之间生产水平的一个中介因素。
