Hur påverkas mjölkkornas tidsbudget, mjölkavkastning och foderintag av tiden i väntfållan i AMS?

Sammanfattning: Automatic milking systems (AMS) are used in many countries worldwide, and it is an efficient system with several benefits for both the farmer and the dairy cows. The cows can move freely in the barn and they therefore decide to a large extent over their own time budget throughout the day. The cows are kept in loose housing systems and the cow traffic in the barn has an important role in the production. The milking frequency in AMS usually increases compared with conventional morning and evening milking systems and thus the milk yield can also be higher in AMS. In guided cow traffic systems, there is a waiting area in front of the milking robot that only cows with milking permissions have access to. In the waiting area, the cows wait to be milked and are then released to the feeding area or to the lying area depending on cow traffic system. Studies have shown that some cows, mostly animals with a low social rank spend a long time in the waiting area which may have a negative impact on cow welfare, and it can also lead to a decline in production. This study, therefore, aims at investigating whether time in the waiting area affects the time budget of the cows’ feed intake and milk yield. The study included a literature review, analysis of existing data that had been collected in the AMS unit at the Swedish livestock research centre, Lövsta SLU Uppsala and a behavior study in the same unit but at a later time. The behaviour study included 54 dairy cows, of the Swedish Red Breed (SRB) and Holstein. The study intended to determine the cows’ time budget in order to evaluate effects of longer or shorter waiting time on cow activities. The result of the study showed that milking intervals increased by 0.3 minutes for each minute the cows were in the waiting area. Milk yield also increased with increased waiting time by 0.026 kg for every minute. There was no difference between cows in first parity and older cows or between the breeds in milking interval or milk yield. Feed intake was not affected by the time in the waiting area and there was no difference between the breeds in the existing data being analyzed. On the other hand, the roughage intake differed significantly for both breed and lactation numbers in the behavioral study. Holstein cows consumed 2.5 kg DM more per day than SRB cows. Older cows consumed 8.7 kg DM more than first parity cows per day. In the time budget, there was a difference between young and older cows, where the first parity cows showed on average 98 minutes longer standing time in the system than older cows each day. Older cows ruminated 79 minutes longer a day compared to first parity cows, 581 minutes and 502 minutes, respectively. The behavioral study showed that first parity cows waited an average of 238 minutes and older cows waited 115 minutes per day in the waiting area. Data from the milking robot also showed a significant difference between lactations but with shorter waiting times, 163 minutes for first parity cows and 95 minutes for older cows. This data also showed a significant difference between the breeds where SRB cows waited longer time than Holstein cows, 156 minutes and 102 minutes, respectively.