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.

In modern dairy production the milking frequency is increased in some herds due to introducing of automatic milking systems or the farmers decision to milk high producing dairy cows more than two times a day. With more frequent milkings the milk yield increases while the content of fat and protein decreases. However, how the composition of protein is influenced is not fully evaluated. The purpose of this study was therefore to see if a higher milking frequency had any impact on the milk production and especially on the protein composition. This study was conducted as a half udder experiment.

The relatively poor economy in European dairy farming might be improved from efficient feeding systems and dietary management. Increasing herd sizes and transition to loose housing systems in Sweden, increases the possibilities for other feeding systems than separate feeding that is the traditional feeding system in Sweden. Other possible feeding systems are partial mixed ration (PMR) and total mixed ration (TMR), where the TMR system sometimes is associated with overfeeding and thereby increased environmental impact and high feed cost. Diets providing nutrients above or below animal requirements are considered as unbalanced, which in turn are associated with reductions in health, fertility and milk production. On the other hand, a balanced feed ration improves feed efficiency, nitrogen utilization and profitability.

Investment costs for eight different type housing systems for dairy cows has been calculated in order to compare the building costs as a function of herd size, shelter type and automatization. A commercial calculation programme for building was used and complemented with prices of equipments specific for dairy cow building. Herd sizes were 120, 250 and 400 cows. The milking equipments were automatic milking system (AMS), parallel parlour with 32 stalls (2x16) and rotary parlour with 24 stalls. Shelter was either insulated equipped with automatic cable driven scrapers on solid alleys, automatic feed wagon on rails, or uninsulated with manual manure handling and a tractor driven mobile mixer wagon on a drive-through feeding table. Building cost per cow or per kg milk was calculated using an average life time and 6 % interest rate and annual milk yield is 9 500 kg/cow and year. Structure effect 3-4 % higher for an insulated structure than in an uninsulated for 400 and 120 herd respectively. This is much lower compared to what is normally argued.

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.

The coproduct, dried distillers grains + solubles (DDGS) from ethanol production based on wheat contains much rumen degradable protein and fiber with low digestibility. To compliment this quality in an effective way a grass silage low in protein and much digestible fiber is needed. The aim of the study was to investigate the effects of adjusting the crude-protein concentration and fiber quality of the silage when feeding DDGS and of varying the inclusion level of DDGS, when feeding the adjusted grass silage, on intake, milk yield and composition, faecal traits and feed efficiency. Four different total mixed rations were compared. The normal grass-clover silage had a crude protein content of 17,8 % and an NDF content of 46,2 % of dry matter. The adapted grass silage had a crude protein content of 14,6 % and an NDF content of 52,9 % of dry matter. The diets were formulated to have similar nutritional content except for A + 4 which had a higher content of rumen degradable crude protein and a lower concentration of NDF.

Protecting the environment has with time grown to take a more central role in the society. Agriculture plays an important role in the society since this sector produces our food. More thorough research on how agriculture affects the environment is therefore motivated. This research can be used to improve the agricultural practice from an environmental point of view. This is something that both the farmers and the consumers can profit from. This study aims to form the basis for creating environmental indicators for use of nitrogen and energy on dairy farms. Twenty-three farmers in western Sweden have been interviewed about their farms, both organic and conventional. They produce milk with different intensity, defined as the amount of milk delivered (sold) per hectare of arable land.

To enjoy the richness of the grazing cows and high yield during the summers, even during the winter, cheese has been the way to store milk for thousands of years. Nowadays yield is high all year around and the cheese production is possible during all seasons. The aim of this paper is to investi-gate how and why the seasons influence taste and texture of pressed and ripened cheese. Milk is composed of proteins, fat, lactose and water but contains also a lot of vitamins. The quality of milk is very important for the final constitution of cheese.

Automatic milking systems (AMS) are part of a growing trend in Sweden and the number of milk-producing farms is decreasing rapidly. One main reason for the AMS is its ability to facilitate work for the farmer. The effects of introduction prior to calving have not been documented earlier and farmers are not in agreement, however they seldom see a problem with the introduction. The aim of this report is to find differences between two groups of heifers, where one group is trained i.e. introduced to the AMS before calving and the other group is introduced after calving.

Subclinical mastitis (SCM) is a well-known problem in the dairy sector, where it causes severe economic losses mainly due to reduced milk production. This is a problem not only in the western world but also in developing countries. Surveys from different developing countries have shown a SCM prevalence of 52.4 ? 88.6 % at cow level and 26.7 ? 63.2 % at quarter-level. To combat mastitis is important to optimize the milk production of the cow.

The present climate discussion has made energy efficiency an interesting topic. Saving energy does not only help the climate but also saves money for the energy consumer. The purpose of this thesis was to examine the potential of heat recovering from milk cooling. Two milk farms, one with voluntary milking system, VMS, and the other with conventional milking system was used to measure interesting temperatures and electricity consumptions. The numbers were used both to do theoretical calculations and to construct a SIMULINK model. To calculate the potential for heat at milk farms theoretical calculations were made in MATLAB using a reference farm with different combinations of heat recovery and pre cooling. The farm was assumed to keep a dwelling house with the annual heat consumption 18165 kWh.

The aim with the literature study is to inform about the risks that exists in large dairy farms(with focus on mastitis and hoof health) and to inform about the milk industry in Sweden.Personal comments from two study visits (Nötcenter Viken and Vadsbo Mjölk AB) arelinked together with the literature and forms into a discussion regarding sustainableagriculture versus the milk cow's welfare.The profitability for Sweden's milk farmers have decreased because of the decreased milkprice and current inflation. This leads to an increase in herdsize in order to make a profit.The milk cow herds in Sweden becomes fewer year by year and the herdsize increases. Theincreased herdsize can cause a decrease in the time the farmer spends per animal. This canaffect early disease detection and prolong the animals suffering.Swedish Board of Agriculture published (2008) statistics showing that today's milk cow ismedicated primarily because of two reasons; mastitis or hoof problems. Mastitis is thereason to two thirds of all treatments that are carried out.

Milkability or ease of milking, has higher importance today for Swedish dairy cattle producers after the introduction of milking parlours and automatic milking systems. Milkability is the cow?s ability to quickly milk out and be completely milked. There are several measures of milkability available. Today the farmer measures the traits subjectively in relation to the conformation scoring of the cow 30-270 days after her first calving.

Cows are ruminants and they need fibers in their feed and sufficient eating time to function psychologically and physiologically. Many of our cows don?t get enough forage and too much concentrates, which given in the wrong way may cause health and behavior problems. Too much concentrates at once makes the pH in the rumen sink and this may cause decreased fiber utilization since the microbes in the rumen are negatively affected by this. The cow may also get serious problems such as laminitis and abomasal dislocation.

The aim of this study was to examine if the predictions of the herbage quality in the software Grazemore Decision Support System (DSS) gives a reliable ground for milk production in the north of Scandinavia. Pasture samples from one research farm (Umeå) and one organic farm (Nordingrå) was analysed on crude protein and organic matter digestibility. The results were statistically compared to the predicted values. Measured and predicted herbage mass was compared and a control if the predictions of milk production improved if the predicted input were replaced by the values from the analysis, was made. The concentration of crude protein was underestimated by the model on both farms and the relationship between actual and predicted values was poor. Mean Prediction Error (MPE) was 24% and 31% respectively.