The animal welfare act in Sweden states that Dairy cows need to have at least a dim light present at night, but there are no recommendations for what intensity the light should have. It is unknown how cows perceive and react to low light intensities and earlier studies on this topic are limited. Red light as night light has also been suggested, based on the cows? inability to perceive red light. This have however been questioned. The aim with this study was to investigate how four different light intensities affect Dairy cows behavior.

Compared with a few years ago, the cost of concentrates has increased substantially and because of that an increased proportion of pasture is of interest. Pasture is cheap and the farmer does not have to harvest when the cows do it themselves by grazing. This saves both money and time. According to research milk yield decrease with an increasing proportion of pasture in the diet. This is because cows on pasture will have lower dry matter intake than cows with supplements.

This study was performed to investigate the possibility to use ultrasonography as a diagnostic tool for sub-clinical mastitis in Dairy cows. Five cows with high cell counts, and four cows with low cell counts were selected as cases and controls, respectively, and their udders examined with ultrasound during a 5 week period. The image of the udders of cows with high cell counts exhibited small, hyper-echoic, rounded foci, approximately 1 cm in diameter, near the milk cisterns and the base of the teats. These changes were not found consistently in all cows with high cell count, however. Ultrasonography may be a valuable complementary tool in the diagnosis of sub-clinical mastitis in dairy cow, but more cases need to be monitored before its full value can be ascertained..

Drinking water from drilled wells has a high content of iron and other minerals in many places in Sweden. Questions about the association between the quality of drinking water and the health of Dairy cows are regulary asked both by advisers and dairy farmers. There are so far not many studies published about the relevance for high iron content in water and dairy cow health and production. Therefore, the aim of this study was to investigate if there is a connection between the iron content in water and the health of Dairy cows. Initially a literature study was made about iron and it´s function in ruminants.

In the dairy production it is necessary to be able to sort cows. Dairy cows are sorted for many different reasons i.e. regrouping into production strings or for treatments i.e. inseminations, pregnancy and health checks, vaccinations or hoof trimmings. One labour saving way of conducting sorting is by using an automatic sort gate.

Information regarding cows grazing behaviour and time spent grazing can be of great interest to dairy farmers, since this information can indicate how well suited the pasture is to the cows. Feed intake at pasture is however challenging to measure. Automated systems for monitoring the behaviour of cows within dairy production have become increasingly important and relatively common. The aim of this study was to validate an activity measuring device (HOBO® G Logger Pendant Data Logger, USA), a triaxial accelerometer that registers the cow?s head positions during grazing, in order to see if cows? grazing behaviour on pasture could be distinguished from their non grazing behaviour.

The purpose with the study was to find a pattern in the behaviour of Dairy cows which could be related to their social rank. A behavioural study was conducted at the University Cattle Research Centre (Kungsängen) in Uppsala, Sweden. The study included 12 lactating Dairy cows, 6 high ranked and 6 low ranked. The cows were housed in a loose housing barn with an automatic milking system (AMS) to which they had access 24 hours a day. During the experiment the total number of cows in the barn was 46.

Today, there are no regulations saying that cows must have access to some kind of shelter at pasture during the summer. In more tropical countries, it is well-known that Dairy cows might suffer from heat stress when exposed to sun and high temperatures. The well-being of the cows is thereby reduced and the production may also decrease. In Sweden, no research has been done in the area and therefore it is now a clear need of improved knowledge.The purpose of this study was to investigate the importance of shade for Dairy cows in Sweden. The behaviour of 30 cows was examined to see any differences between cows with access to shade and cows without access to shade.

Heat stress negatively influences the performance of dairy cattle such as lactation and reproduction. Heat stress can cause production losses as well as welfare problems. Years of research have shown that heat stress is a huge problem for dairy cattle in both the tropics and temperate zones but no such research have so far been done in northern European countries. It seems like shade is an important tool when improving pasture conditions and therefore deserves more attention. The aim with this study was to investigate whether there is a need of providing shade for grazing Dairy cows during the summer in Sweden. Two groups of lactating Swedish Red Dairy cows (n=15 per group) were kept on pasture.

Today a trend can be seen towards fewer dairy farms and increasing number of cows per farm. Larger farms set a higher demand of more labour efficient milking systems. The time to enter and exit milking rotary platforms is crucial to maintain a high cow throughput. This study is a project initiated by DeLaval in order to evaluate the cow throughput and cow behaviour during entry and exit in two types of parallel external rotaries with different bail designs. The two rotaries compared were DeLaval parallel rotary PR2100 and PR3100HD.

Today automatic milking systems (AMS) are growing in popularity. In these systems the cows are loose and have to get to the robot and the feed on their own. The cows ranking in this system affect their welfare. In this study data from seven years in an AMS was used and analysed. The aim was to investigate how ranking could affect the behaviour of the cows at milking and at feeding.

Today dairy farmers in Sweden are obligated to have lights turned on during night time in addition to the mandatory daylight inlet. This presents a cost for the production but many argue that it can be economically beneficial, especially in loose housing of Dairy cows. In loose housing and even more so in herds with automatic milking, well functioning cow traffic during all hours of the day is crucial to optimise production. In order to keep the cow traffic flowing, lights may be an important management tool. It is also perceived among farmers with tied up stall that night light decreases the incidents of cows accidental stepping on their own or neighbours udders.

Time studies in dairy production are an essential tool when deciding about level of mechanisation and automatisation both in investment situation and improving efficiency in existing operations. In previous investigations such studies have been carried out during normal barn conditions during winter. Since there is a compulsory to have Dairy cows grazing 3 to 5 months during summer time in Sweden time studies during this season is important to have a full picture of needed working time. During grazing season time studies was carried out at 14 dairy farms representing herd sizes from 66 to 450 Dairy cows of which 6 farms with AMS. 8 farms were the same as studied during winter season.

To get a good economy on the dairy farms the fertility control of heifers and cows is a crucial factor. It is also important to know which key parameters that should be tracked. In this work well established routines for heat detection have to be applied. When the dairy farmers use technical aid in estrus control it is important not to forget that technical aids can not replace the human eye. Approximately 50 % of all opportunities to inseminate are missed because clear signs of estrus have not been displayed and/or recorded. The cattle fertility has been declining over recent years. During the same time the cow?s proceeds have increased, consequently applying a higher pressure on the cow and the manager.

Cows affected by mastitis caused by Klebsiella (K.) pneumoniae often become seriously ill. In some cases herdproblems may occur. Contaminated bedding material is considered to be one of the most common risk factors for klebsiella mastitis. In a recently performed study in USA it was found, however, that more than 80 % of healthy, lactating Dairy cows excreted K. pneumoniae in faeces.