The presence of cystic ovarian follicles represents an important ovarian dysfunction and is a major cause of reproductive failure in dairy cattle. A cystic ovarian follicle is a persistent follicular-like structure on one or both of the ovaries. It is at least 2,5cm in diameter and it has to persist for at least ten days while a corpus luteum is missing. There are two kinds of cystic ovarian follicles, those who have a progesterone production and those who have not. A clear definition for this condition is lacking, probably because the heterogeneity of the clinical signs and the complexity of the disorder.

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.

The aim of this study was to investigate the relationship between sleep, photoperiod, milk yield and hormones connected to milk formation. Variations of prolactin (PRL) and Insulin-Like growth factor-1 (IGF-1) in plasma were measured during two different light programs. The light programs consisted of either 24 hours of light (L24:D0) or four hours of light and 20 hours of darkness (L4:D20). Five Cows of the Swedish Red breed were used in a cross-over experiment and each light program consisted of five days. Milk yield was measured at every milking and milk samples were analyzed with regard to fat, lactose and protein.

Automatic rumination measuring can be applied as a health indicator in dairy farming but is also highly desirable for research purposes. This study aimed to validate the technical functionality of the product RuminActTM, which employ acoustics to monitor rumination duration. The time budget of high yielding Cows was studied and possible differences in rumination time between 13 rations were interpreted. Further the study examined what affects daily rumination and rumination efficiency. The validation was performed with direct observations that were compared to the automatically recorded rumination durations.

This thesis consists of four case studies. The objective is to find out how to get a well functioning cow traffic in an automatic milking system. Different technical and building solutions are analysed and some adjustments are proposed for the DeLaval herd management software. Case study 1: Lactation chart comparison from traditional cow traffic and Feed First? cow traffic Case study 2: Farm A - a study of the precedence passage and the cow traffic Case study 3: Farm B ? an overview of the farm and their way of working Case study 4: Key factors ? how can we judge how well a VMS farm is working? Case study 1: Lactation chart comparison from traditional cow traffic and Feed First? cow traffic In this survey data is analysed from before and after rebuilding to Feed First? cow traffic. Lactation graphs are compared between traditional cow traffic and Feed First? cow traffic.

Live-weight at different ages for Swedish Holsteins (SLB) and for the Swedish Red and White Breed (SRB), and the correlation to heart girth and height at withers. The aim of this investigation was to study the live-weight changes and mature weight for the Swedish Red and White Breed (SRB) and for Swedish Holsteins (SLB), and to estimate the correlations between body weight and body measurements such as heart girth and height at withers, respectively. The material used was from one of the experimental dairy herds (Jälla) of the Swedish University of Agricultural Science. It included recordings on 293 dairy Cows with information from 7142 weight occasions and recordings on 275 dairy Cows with information of 557 heart girth measurements and 560 measurements of height at withers. The registrations were done during 1993-2002. There was a large variation in live weight between Cows in different ages and lactation stages.

This work has been done to develop a plan for a future dairy barn at theGästgivaregården and to show the space needed for Cows and replacement heifers. Itwould also show the storage that will be needed. The design was largely based on resultsfrom studies on six different farms, but also the facts that are taken from research papersand articles in order to compare theory with practice. Because some farms only whereinterviewed by phone I have used a query form to obtain comparable resultes.The aim is to build a new barn with Automatic milking. I've drawn a milking stable for120 milking cow and replacement heifers with the capability to house up to 140 milkingCows if the farm would expand in the future.Calculations of feed amounts and space requirements have been made to see how manyhectares are needed to supply the Cows and replacement heifers with feed and to knowabout what size of storage space is required.The investigations made in this writing are to answer questions about the AMS-unit`sposition and how to best maintain a good health status in the herd.

The purpose of this study was to find possible explanations to why the studied herd had an increased incidence of abomasal displacements. The incidence of abomasal displacement in the herd was three times higher than the incidence of an average Swedish herd. The Cows in this study were fed a total mixed ration. The different parameters studied were: energy content in food, nutritional content in food, body condition scoring, concomitant other diseases, and blood parameters of glucose, fructosamine, cholesterol, insulin, betahydroxybutyrat and free fatty acids. The author?s suggestions to decrease the problems are to decrease the energy content in the TMR to lower the Cows? body condition scores in the dry period and changing the content in the TMR to increase the amount of NDF and adding structure in the form of chopped straw.

Sweden signed, in 1992, the Convention on Biological Diversity (CBD) and has thus assumed responsibility for the indigenous biodiversity. That also means that Sweden has a conservation responsibility for the Swedish Friesian (SLB) (SJV, 2007a). In a survey conducted by the Board of Agriculture (SJV) in 1996, it appeared that there were around 780 Cows and heifers of the SLB breed (SJV, 1997). SJV did in 2006 a plan for the development of livestock genet-ic resources and the number of Cows of SLB was estimated at approximately 200. This meant that the SLB was in need of being conserved and SJV assumed it would be categorized as threatened.The primary objective of conservation of a breed is to reduce the loss of the original genetic variation (Lacy et al., 1995).

Sweden signed, in 1992, the Convention on Biological Diversity (CBD) and has thus assumed responsibility for the indigenous biodiversity. That also means that Sweden has a conservation responsibility for the Swedish Friesian (SLB) (SJV, 2007a). In a survey conducted by the Board of Agriculture (SJV) in 1996, it appeared that there were around 780 Cows and heifers of the SLB breed (SJV, 1997). SJV did in 2006 a plan for the development of livestock genet-ic resources and the number of Cows of SLB was estimated at approximately 200. This meant that the SLB was in need of being conserved and SJV assumed it would be categorized as threatened.The primary objective of conservation of a breed is to reduce the loss of the original genetic variation (Lacy et al., 1995).

Mastitis, inflammation in the udder tissue, caused by S. aureus is a big problem in dairy cattle production. It causes suffering for the cow and curing or replacing the infected cow is costly for the farmer. It is known that beef cattle also suffer from mastitis caused by S. aureus.

SUMMARY By altering the longitudinal slopes of the cubicle floors the drainage could be improved. If the altered slopes also position the Cows further back in the cubicles the effect could be cleaner lying surfaces. In result this would lead to lower labour requirements, cleaner Cows, cleaner udders and a minimization of the risks of mastitis. However, if the altered slopes lead to that the Cows position themselves more diagonally in the cubicles the positive effects could be reduced. The altered slopes could even have a negative influence on the animals? natural lying behaviour.

Milk yield levels in dairy Cows are influenced by many factors such as nutrition, breed, health status, management and environment. This study was conducted among small scale farmers in Zambia, where the climate can be dry for up to six months per year and cause a lack of green pasture for livestock and on-farm produced feed. The purpose of this study was to identify management factors that can influence milk yield at small scale dairy farms in Zambia, and present advice that could improve productivity, without the need of expensive investments. The study included semi-structured questionnaires presented to the farmers (n=29) including questions about cattle management and milk production. Testing of somatic cell count (SCC) with DCC (DeLaval Cell Counter) from herd milk samples (n=56) and observation of housing and animal body condition on-farm was also made.

The purpose with this literature study was to investigate the possibilities for improvement of forage protein in dairy Cows with focus on feeding strategies and conservation of forage protein. The utilization of forage protein in dairy Cows is often not that efficient as it could be. The feed crude protein consists of both true proteins and non protein nitrogen. The digestion of proteins in the rumen depends on the protein degradation rate and the ability of the microbes to synthesize microbial protein. The microbes need a balance between carbohydrates that provide them with energy and proteins that are degradable in the rumen.

When Cows in Sweden are inseminated the heat strength is reported to the Swedish milk-recording scheme and AI scheme. Cows that show strong signs of estrus are desirable and the trait is included in the Swedish breeding goal. A strong heat makes it easier to inseminate at the right time and to avoid long and expensive days open. Since ten years the heat strength is scored from one to five by the farmer and reported to the milk-recording scheme and AI scheme. Earlier the score was from one to three and the decision was made by the AI technician.