Duplessis M, Vasseur E, Ferland J, Pajor E A, DeVries T J, Pellerin D
Centre de recherche et développement de Sherbrooke, Sherbrooke, QC, J1M 0C8, Canada.
Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
JDS Commun. 2021 Jun 23;2(4):212-216. doi: 10.3168/jds.2021-0082. eCollection 2021 Jul.
Adoption of automated milking systems (AMS) has increased exponentially around the world in recent years. The objective of this observational study was to evaluate how producer perception of changes in cow-average milk yield and somatic cell count (SCC) compared with the actual changes in their herds after the introduction of AMS in Canadian commercial dairy herds. Data were collected (in 2014 and 2015) through a survey of 97 Canadian dairy herds that shifted to AMS from 2000 to 2014. Producers were asked their perception about milk yield and SCC changes (increase, decrease, or no change) after AMS introduction. Actual herd performance data were obtained from dairy herd improvement organizations. Differences between the 12-mo rolling herd-average milk yield (kg/cow per year) and SCC (cells/mL) at the closest test 2 yr after transitioning to AMS and at the last test before the transition were calculated and compared with the producer perception answers. After AMS adoption, milking herd size, milk yield, SCC, and number of AMS units per herd averaged (± standard deviation) 99.8 ± 54.4 cows, 9,619 ± 1,354 kg/cow per year, 248,825 ± 97,286 cells/mL, and 1.9 ± 1.1 units, respectively. On average, after AMS introduction, herd size, milk yield, and culling rate increased by 11.3 cows, 441 kg/cow per year, and 1.3%, respectively, and calving interval decreased by 7 d. For producers who perceived an increase, actual milk yield and SCC increases averaged (mean ± standard deviation) +534 ± 1,003 kg/cow per year and +56,679 ± 66,662 cells/mL, respectively. Alternatively, for producers who perceived a decrease, actual milk yield and SCC decreases averaged -984 ± 658 kg/cow per year and -26,976 ± 94,099 cells/mL, respectively. An actual milk yield change of +83.1 ± 1,113.3 kg/cow per year and an SCC change of +6,135 ± 72,609 cells/mL were observed in the herds in which the dairy producers perceived no change with the AMS introduction. Hence, dairy producers were, on average, able to discern their actual milk yield and SCC changes after AMS adoption. However, the proportions of dairy producers who accurately perceived their actual milk yield and SCC changes after AMS introduction were 39.4% for milk yield (increase: 36.3%; decrease: 100.0%; and no change: 45.5%) and 46.7% for SCC (increase: 50.0%; decrease: 39.0%; and no change: 54.1%). From these results, we concluded that several dairy producers distorted their actual milk yield and SCC changes or were not fully aware of those changes.
近年来，自动挤奶系统（AMS）在全球范围内的采用呈指数级增长。这项观察性研究的目的是评估加拿大商业奶牛场引入AMS后，生产者对奶牛平均产奶量和体细胞计数（SCC）变化的认知与牛群实际变化情况的对比。通过对97个于2000年至2014年期间转而采用AMS的加拿大奶牛场进行调查（在2014年和2015年）收集数据。询问生产者关于引入AMS后产奶量和SCC变化（增加、减少或无变化）的看法。实际牛群生产性能数据从奶牛群改良组织获取。计算向AMS过渡后最近一次检测时和过渡前最后一次检测时的12个月滚动牛群平均产奶量（千克/头/年）和SCC（细胞/毫升）之间的差异，并与生产者的认知答案进行比较。采用AMS后，挤奶牛群规模、产奶量、SCC以及每群AMS设备数量平均（±标准差）分别为99.8±54.4头奶牛、9619±1354千克/头/年、248825±97286细胞/毫升和1.9±1.1套设备。平均而言，引入AMS后，牛群规模、产奶量和淘汰率分别增加了11.3头奶牛、441千克/头/年和1.3%，产犊间隔缩短了7天。对于认为产奶量增加的生产者，实际产奶量和SCC增加平均（均值±标准差）分别为+534±1003千克/头/年和+56679±66662细胞/毫升。相反，对于认为产奶量减少的生产者，实际产奶量和SCC减少平均分别为-984±658千克/头/年和-26976±94099细胞/毫升。在奶农认为引入AMS后无变化的牛群中，观察到实际产奶量变化为+83.1±1113.3千克/头/年，SCC变化为+6135±72609细胞/毫升。因此，奶农平均能够辨别引入AMS后他们牛群的实际产奶量和SCC变化。然而，引入AMS后准确认知其实际产奶量和SCC变化的奶农比例，产奶量方面为39.4%（增加：36.3%；减少：100.0%；无变化：45.5%），SCC方面为46.7%（增加：50.0%；减少：39.0%；无变化：54.1%）。从这些结果我们得出结论，一些奶农歪曲了他们牛群实际的产奶量和SCC变化，或者没有完全意识到这些变化。
