The objective of the study was to compare 305-day lactation milk yield in first and second lactations and selected fertility traits (number of services per conception, service period (days between first and last insemination), age at insemination and calving, gestation length, calving to conception period, calving interval period) in 2620 conventionally and automatically milked Polish Holstein-Friesian cows during the first two reproductive cycles. The study was conducted in 16 dairy herds that had been transitioned from a conventional milking system (CMS) to an automatic milking system (AMS) in the years 2010–2013. Sources of variation for the traits measured, including the milking system, were tested by multifactorial analysis of variance and the generalized linear model using a Poisson and negative binomial models and log link function using SAS. After switching from a conventional to an automatic milking system, milk yield increased by 1078.35 and 1182.24 kg in first- and second-lactation cows, respectively. In terms of fertility traits, the change in the milking system had a significant effect only on service period in the first reproductive cycle (CMS–22 days; AMS–15 days) and the number of inseminations needed for pregnancy (CMS–2.01; AMS–1.79) and on age at calving (CMS–1244; AMS–1226 days) in the second reproductive cycle. It must be emphasized that more favourable fertility traits (except for the calving to conception period in the second reproductive cycle) were observed in the group of automatically compared to conventionally milked cows. The interaction between herd and milking system was significant for most of the examined traits.

这项研究的目的是比较第一次和第二次哺乳期的305天泌乳量和所选的生育力特征（每个受孕的服务次数，服务时间（第一次和最后一次授精之间的天数），授精和产犊的年龄，孕期，通常在2620年分娩至受孕期，产犊间隔期，并在前两个生殖周期内自动挤奶波兰荷斯坦奶牛。该研究在16个奶牛群中进行，这些奶牛群在2010-2013年间已从常规挤奶系统（CMS）过渡到自动挤奶系统（AMS）。所测量特征的变异来源，包括挤奶系统，通过方差的多因素分析和使用Poisson和负二项式模型的广义线性模型以及使用SAS的对数链接函数进行了检验。从常规挤奶系统切换到自动挤奶系统后，第一泌乳和第二泌乳母牛的产奶量分别增加了1078.35和1182.24 kg。就生育性状而言，挤奶系统的变化仅对第一个生殖周期（CMS-22天； AMS-15天）的服务期和怀孕所需的授精次数（CMS-2.01； AMS）有显着影响–1.79）和第二个生殖周期中产犊的年龄（CMS–1244； AMS–1226天）。必须强调的是，与常规奶牛相比，在自动组中观察到了更有利的生育性状（除了第二个生殖周期的受孕期）。牛群和挤奶系统之间的相互作用对于大多数检查的性状都是重要的。